[dev.cc] cmd/5g etc: code cleanup: delay var decls and eliminate dead code

Ran rsc.io/grind rev 6f0e601 on the source files.

The cleanups move var declarations as close to the use
as possible, splitting disjoint uses of the var into separate
variables. They also remove dead code (especially in
func sudoaddable), which helps with the var moving.

There's more cleanup to come, but this alone cuts the
time spent compiling html/template on my 2013 MacBook Pro
from 3.1 seconds to 2.3 seconds.

Change-Id: I4de499f47b1dd47a560c310bbcde6b08d425cfd6
Reviewed-on: https://go-review.googlesource.com/5637
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/src/cmd/internal/gc/align.go b/src/cmd/internal/gc/align.go
index 994b7a2..a588ca3 100644
--- a/src/cmd/internal/gc/align.go
+++ b/src/cmd/internal/gc/align.go
@@ -22,11 +22,8 @@
 }
 
 func offmod(t *Type) {
-	var f *Type
-	var o int32
-
-	o = 0
-	for f = t.Type; f != nil; f = f.Down {
+	o := int32(0)
+	for f := t.Type; f != nil; f = f.Down {
 		if f.Etype != TFIELD {
 			Fatal("offmod: not TFIELD: %v", Tconv(f, obj.FmtLong))
 		}
@@ -40,19 +37,14 @@
 }
 
 func widstruct(errtype *Type, t *Type, o int64, flag int) int64 {
-	var f *Type
-	var w int64
-	var maxalign int32
-	var starto int64
-	var lastzero int64
-
-	starto = o
-	maxalign = int32(flag)
+	starto := o
+	maxalign := int32(flag)
 	if maxalign < 1 {
 		maxalign = 1
 	}
-	lastzero = 0
-	for f = t.Type; f != nil; f = f.Down {
+	lastzero := int64(0)
+	var w int64
+	for f := t.Type; f != nil; f = f.Down {
 		if f.Etype != TFIELD {
 			Fatal("widstruct: not TFIELD: %v", Tconv(f, obj.FmtLong))
 		}
@@ -118,11 +110,6 @@
 }
 
 func dowidth(t *Type) {
-	var et int32
-	var w int64
-	var lno int
-	var t1 *Type
-
 	if Widthptr == 0 {
 		Fatal("dowidth without betypeinit")
 	}
@@ -136,7 +123,7 @@
 	}
 
 	if t.Width == -2 {
-		lno = int(lineno)
+		lno := int(lineno)
 		lineno = int32(t.Lineno)
 		if t.Broke == 0 {
 			t.Broke = 1
@@ -157,12 +144,12 @@
 	// defer checkwidth calls until after we're done
 	defercalc++
 
-	lno = int(lineno)
+	lno := int(lineno)
 	lineno = int32(t.Lineno)
 	t.Width = -2
 	t.Align = 0
 
-	et = int32(t.Etype)
+	et := int32(t.Etype)
 	switch et {
 	case TFUNC,
 		TCHAN,
@@ -177,7 +164,7 @@
 		}
 	}
 
-	w = 0
+	w := int64(0)
 	switch et {
 	default:
 		Fatal("dowidth: unknown type: %v", Tconv(t, 0))
@@ -233,13 +220,13 @@
 
 		// make fake type to check later to
 		// trigger channel argument check.
-		t1 = typ(TCHANARGS)
+		t1 := typ(TCHANARGS)
 
 		t1.Type = t
 		checkwidth(t1)
 
 	case TCHANARGS:
-		t1 = t.Type
+		t1 := t.Type
 		dowidth(t.Type) // just in case
 		if t1.Type.Width >= 1<<16 {
 			Yyerror("channel element type too large (>64kB)")
@@ -277,11 +264,9 @@
 			break
 		}
 		if t.Bound >= 0 {
-			var cap uint64
-
 			dowidth(t.Type)
 			if t.Type.Width != 0 {
-				cap = (uint64(Thearch.MAXWIDTH) - 1) / uint64(t.Type.Width)
+				cap := (uint64(Thearch.MAXWIDTH) - 1) / uint64(t.Type.Width)
 				if uint64(t.Bound) > cap {
 					Yyerror("type %v larger than address space", Tconv(t, obj.FmtLong))
 				}
@@ -311,7 +296,7 @@
 		// make fake type to check later to
 	// trigger function argument computation.
 	case TFUNC:
-		t1 = typ(TFUNCARGS)
+		t1 := typ(TFUNCARGS)
 
 		t1.Type = t
 		checkwidth(t1)
@@ -322,7 +307,7 @@
 		// function is 3 cated structures;
 	// compute their widths as side-effect.
 	case TFUNCARGS:
-		t1 = t.Type
+		t1 := t.Type
 
 		w = widstruct(t.Type, *getthis(t1), 0, 0)
 		w = widstruct(t.Type, *getinarg(t1), w, Widthreg)
@@ -382,8 +367,6 @@
 var tlq *TypeList
 
 func checkwidth(t *Type) {
-	var l *TypeList
-
 	if t == nil {
 		return
 	}
@@ -404,7 +387,7 @@
 	}
 	t.Deferwidth = 1
 
-	l = tlfree
+	l := tlfree
 	if l != nil {
 		tlfree = l.next
 	} else {
@@ -425,12 +408,10 @@
 }
 
 func resumecheckwidth() {
-	var l *TypeList
-
 	if defercalc == 0 {
 		Fatal("resumecheckwidth")
 	}
-	for l = tlq; l != nil; l = tlq {
+	for l := tlq; l != nil; l = tlq {
 		l.t.Deferwidth = 0
 		tlq = l.next
 		dowidth(l.t)
@@ -442,18 +423,11 @@
 }
 
 func typeinit() {
-	var i int
-	var etype int
-	var sameas int
-	var t *Type
-	var s *Sym
-	var s1 *Sym
-
 	if Widthptr == 0 {
 		Fatal("typeinit before betypeinit")
 	}
 
-	for i = 0; i < NTYPE; i++ {
+	for i := 0; i < NTYPE; i++ {
 		Simtype[i] = uint8(i)
 	}
 
@@ -463,7 +437,7 @@
 	Types[TPTR64] = typ(TPTR64)
 	dowidth(Types[TPTR64])
 
-	t = typ(TUNSAFEPTR)
+	t := typ(TUNSAFEPTR)
 	Types[TUNSAFEPTR] = t
 	t.Sym = Pkglookup("Pointer", unsafepkg)
 	t.Sym.Def = typenod(t)
@@ -475,7 +449,7 @@
 		Tptr = TPTR64
 	}
 
-	for i = TINT8; i <= TUINT64; i++ {
+	for i := TINT8; i <= TUINT64; i++ {
 		Isint[i] = 1
 	}
 	Isint[TINT] = 1
@@ -502,7 +476,7 @@
 	/*
 	 * initialize okfor
 	 */
-	for i = 0; i < NTYPE; i++ {
+	for i := 0; i < NTYPE; i++ {
 		if Isint[i] != 0 || i == TIDEAL {
 			okforeq[i] = 1
 			okforcmp[i] = 1
@@ -566,6 +540,7 @@
 
 	okforcmp[TSTRING] = 1
 
+	var i int
 	for i = 0; i < len(okfor); i++ {
 		okfor[i] = okfornone[:]
 	}
@@ -655,6 +630,10 @@
 	Simtype[TUNSAFEPTR] = uint8(Tptr)
 
 	/* pick up the backend thearch.typedefs */
+	var s1 *Sym
+	var etype int
+	var sameas int
+	var s *Sym
 	for i = range Thearch.Typedefs {
 		s = Lookup(Thearch.Typedefs[i].Name)
 		s1 = Pkglookup(Thearch.Typedefs[i].Name, builtinpkg)
@@ -703,13 +682,11 @@
  */
 func Argsize(t *Type) int {
 	var save Iter
-	var fp *Type
-	var w int64
 	var x int64
 
-	w = 0
+	w := int64(0)
 
-	fp = Structfirst(&save, Getoutarg(t))
+	fp := Structfirst(&save, Getoutarg(t))
 	for fp != nil {
 		x = fp.Width + fp.Type.Width
 		if x > w {
diff --git a/src/cmd/internal/gc/bits.go b/src/cmd/internal/gc/bits.go
index 23da356..95421e5 100644
--- a/src/cmd/internal/gc/bits.go
+++ b/src/cmd/internal/gc/bits.go
@@ -67,9 +67,7 @@
 }
 */
 func bany(a *Bits) bool {
-	var i int
-
-	for i = 0; i < BITS; i++ {
+	for i := 0; i < BITS; i++ {
 		if a.b[i] != 0 {
 			return true
 		}
@@ -90,10 +88,9 @@
 }
 */
 func bnum(a Bits) int {
-	var i int
 	var b uint64
 
-	for i = 0; i < BITS; i++ {
+	for i := 0; i < BITS; i++ {
 		b = a.b[i]
 		if b != 0 {
 			return 64*i + Bitno(b)
@@ -105,9 +102,7 @@
 }
 
 func blsh(n uint) Bits {
-	var c Bits
-
-	c = zbits
+	c := zbits
 	c.b[n/64] = 1 << (n % 64)
 	return c
 }
@@ -125,9 +120,7 @@
 }
 
 func Bitno(b uint64) int {
-	var i int
-
-	for i = 0; i < 64; i++ {
+	for i := 0; i < 64; i++ {
 		if b&(1<<uint(i)) != 0 {
 			return i
 		}
@@ -140,9 +133,8 @@
 	var fp string
 
 	var i int
-	var first int
 
-	first = 1
+	first := 1
 
 	for bany(&bits) {
 		i = bnum(bits)
diff --git a/src/cmd/internal/gc/bv.go b/src/cmd/internal/gc/bv.go
index 002b5a4..e7fdd70 100644
--- a/src/cmd/internal/gc/bv.go
+++ b/src/cmd/internal/gc/bv.go
@@ -63,16 +63,13 @@
 }
 
 func bvconcat(src1 *Bvec, src2 *Bvec) *Bvec {
-	var dst *Bvec
-	var i int32
-
-	dst = bvalloc(src1.n + src2.n)
-	for i = 0; i < src1.n; i++ {
+	dst := bvalloc(src1.n + src2.n)
+	for i := int32(0); i < src1.n; i++ {
 		if bvget(src1, i) != 0 {
 			bvset(dst, i)
 		}
 	}
-	for i = 0; i < src2.n; i++ {
+	for i := int32(0); i < src2.n; i++ {
 		if bvget(src2, i) != 0 {
 			bvset(dst, i+src1.n)
 		}
@@ -90,8 +87,6 @@
 // bvnext returns the smallest index >= i for which bvget(bv, i) == 1.
 // If there is no such index, bvnext returns -1.
 func bvnext(bv *Bvec, i int32) int {
-	var w uint32
-
 	if i >= bv.n {
 		return -1
 	}
@@ -110,7 +105,7 @@
 	}
 
 	// Find 1 bit.
-	w = bv.b[i>>WORDSHIFT] >> uint(i&WORDMASK)
+	w := bv.b[i>>WORDSHIFT] >> uint(i&WORDMASK)
 
 	for w&1 == 0 {
 		w >>= 1
@@ -121,9 +116,7 @@
 }
 
 func bvisempty(bv *Bvec) bool {
-	var i int32
-
-	for i = 0; i < bv.n; i += WORDBITS {
+	for i := int32(0); i < bv.n; i += WORDBITS {
 		if bv.b[i>>WORDSHIFT] != 0 {
 			return false
 		}
@@ -173,21 +166,17 @@
 }
 
 func bvprint(bv *Bvec) {
-	var i int32
-
 	fmt.Printf("#*")
-	for i = 0; i < bv.n; i++ {
+	for i := int32(0); i < bv.n; i++ {
 		fmt.Printf("%d", bvget(bv, i))
 	}
 }
 
 func bvreset(bv *Bvec, i int32) {
-	var mask uint32
-
 	if i < 0 || i >= bv.n {
 		Fatal("bvreset: index %d is out of bounds with length %d\n", i, bv.n)
 	}
-	mask = ^(1 << uint(i%WORDBITS))
+	mask := uint32(^(1 << uint(i%WORDBITS)))
 	bv.b[i/WORDBITS] &= mask
 }
 
@@ -198,11 +187,9 @@
 }
 
 func bvset(bv *Bvec, i int32) {
-	var mask uint32
-
 	if i < 0 || i >= bv.n {
 		Fatal("bvset: index %d is out of bounds with length %d\n", i, bv.n)
 	}
-	mask = 1 << uint(i%WORDBITS)
+	mask := uint32(1 << uint(i%WORDBITS))
 	bv.b[i/WORDBITS] |= mask
 }
diff --git a/src/cmd/internal/gc/closure.go b/src/cmd/internal/gc/closure.go
index c2c802e..20a0349 100644
--- a/src/cmd/internal/gc/closure.go
+++ b/src/cmd/internal/gc/closure.go
@@ -13,12 +13,10 @@
  * function literals aka closures
  */
 func closurehdr(ntype *Node) {
-	var n *Node
 	var name *Node
 	var a *Node
-	var l *NodeList
 
-	n = Nod(OCLOSURE, nil, nil)
+	n := Nod(OCLOSURE, nil, nil)
 	n.Ntype = ntype
 	n.Funcdepth = Funcdepth
 	n.Outerfunc = Curfn
@@ -35,7 +33,7 @@
 	n.Rlist = ntype.Rlist
 	ntype.List = nil
 	ntype.Rlist = nil
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		name = l.N.Left
 		if name != nil {
 			name = newname(name.Sym)
@@ -48,7 +46,7 @@
 		ntype.List = list(ntype.List, a)
 	}
 
-	for l = n.Rlist; l != nil; l = l.Next {
+	for l := n.Rlist; l != nil; l = l.Next {
 		name = l.N.Left
 		if name != nil {
 			name = newname(name.Sym)
@@ -58,15 +56,11 @@
 }
 
 func closurebody(body *NodeList) *Node {
-	var func_ *Node
-	var v *Node
-	var l *NodeList
-
 	if body == nil {
 		body = list1(Nod(OEMPTY, nil, nil))
 	}
 
-	func_ = Curfn
+	func_ := Curfn
 	func_.Nbody = body
 	func_.Endlineno = lineno
 	funcbody(func_)
@@ -75,7 +69,8 @@
 	// ordinary ones in the symbol table; see oldname.
 	// unhook them.
 	// make the list of pointers for the closure call.
-	for l = func_.Cvars; l != nil; l = l.Next {
+	var v *Node
+	for l := func_.Cvars; l != nil; l = l.Next {
 		v = l.N
 		v.Closure.Closure = v.Outer
 		v.Outerexpr = oldname(v.Sym)
@@ -85,12 +80,9 @@
 }
 
 func typecheckclosure(func_ *Node, top int) {
-	var oldfn *Node
 	var n *Node
-	var l *NodeList
-	var olddd int
 
-	for l = func_.Cvars; l != nil; l = l.Next {
+	for l := func_.Cvars; l != nil; l = l.Next {
 		n = l.N.Closure
 		if n.Captured == 0 {
 			n.Captured = 1
@@ -106,13 +98,13 @@
 		}
 	}
 
-	for l = func_.Dcl; l != nil; l = l.Next {
+	for l := func_.Dcl; l != nil; l = l.Next {
 		if l.N.Op == ONAME && (l.N.Class == PPARAM || l.N.Class == PPARAMOUT) {
 			l.N.Decldepth = 1
 		}
 	}
 
-	oldfn = Curfn
+	oldfn := Curfn
 	typecheck(&func_.Ntype, Etype)
 	func_.Type = func_.Ntype.Type
 	func_.Top = top
@@ -123,7 +115,7 @@
 	// underlying closure function we create is added to xtop.
 	if Curfn != nil && func_.Type != nil {
 		Curfn = func_
-		olddd = decldepth
+		olddd := decldepth
 		decldepth = 1
 		typechecklist(func_.Nbody, Etop)
 		decldepth = olddd
@@ -143,16 +135,12 @@
 var closurename_closgen int
 
 func closurename(n *Node) *Sym {
-	var outer string
-	var prefix string
-	var gen int
-
 	if n.Sym != nil {
 		return n.Sym
 	}
-	gen = 0
-	outer = ""
-	prefix = ""
+	gen := 0
+	outer := ""
+	prefix := ""
 	if n.Outerfunc == nil {
 		// Global closure.
 		outer = "glob"
@@ -192,20 +180,17 @@
 }
 
 func makeclosure(func_ *Node) *Node {
-	var xtype *Node
-	var xfunc *Node
-
 	/*
 	 * wrap body in external function
 	 * that begins by reading closure parameters.
 	 */
-	xtype = Nod(OTFUNC, nil, nil)
+	xtype := Nod(OTFUNC, nil, nil)
 
 	xtype.List = func_.List
 	xtype.Rlist = func_.Rlist
 
 	// create the function
-	xfunc = Nod(ODCLFUNC, nil, nil)
+	xfunc := Nod(ODCLFUNC, nil, nil)
 
 	xfunc.Nname = newname(closurename(func_))
 	xfunc.Nname.Sym.Flags |= SymExported // disable export
@@ -239,18 +224,15 @@
 // We use value capturing for values <= 128 bytes that are never reassigned
 // after capturing (effectively constant).
 func capturevars(xfunc *Node) {
-	var func_ *Node
 	var v *Node
 	var outer *Node
-	var l *NodeList
-	var lno int
 
-	lno = int(lineno)
+	lno := int(lineno)
 	lineno = xfunc.Lineno
 
-	func_ = xfunc.Closure
+	func_ := xfunc.Closure
 	func_.Enter = nil
-	for l = func_.Cvars; l != nil; l = l.Next {
+	for l := func_.Cvars; l != nil; l = l.Next {
 		v = l.N
 		if v.Type == nil {
 			// if v->type is nil, it means v looked like it was
@@ -280,13 +262,11 @@
 		}
 
 		if Debug['m'] > 1 {
-			var name *Sym
-			var how string
-			name = nil
+			name := (*Sym)(nil)
 			if v.Curfn != nil && v.Curfn.Nname != nil {
 				name = v.Curfn.Nname.Sym
 			}
-			how = "ref"
+			how := "ref"
 			if v.Byval != 0 {
 				how = "value"
 			}
@@ -303,22 +283,9 @@
 // transformclosure is called in a separate phase after escape analysis.
 // It transform closure bodies to properly reference captured variables.
 func transformclosure(xfunc *Node) {
-	var func_ *Node
-	var cv *Node
-	var addr *Node
-	var v *Node
-	var f *Node
-	var l *NodeList
-	var body *NodeList
-	var param **Type
-	var fld *Type
-	var offset int64
-	var lno int
-	var nvar int
-
-	lno = int(lineno)
+	lno := int(lineno)
 	lineno = xfunc.Lineno
-	func_ = xfunc.Closure
+	func_ := xfunc.Closure
 
 	if func_.Top&Ecall != 0 {
 		// If the closure is directly called, we transform it to a plain function call
@@ -337,15 +304,18 @@
 		//	}(42, byval, &byref)
 
 		// f is ONAME of the actual function.
-		f = xfunc.Nname
+		f := xfunc.Nname
 
 		// Get pointer to input arguments and rewind to the end.
 		// We are going to append captured variables to input args.
-		param = &getinargx(f.Type).Type
+		param := &getinargx(f.Type).Type
 
 		for ; *param != nil; param = &(*param).Down {
 		}
-		for l = func_.Cvars; l != nil; l = l.Next {
+		var v *Node
+		var addr *Node
+		var fld *Type
+		for l := func_.Cvars; l != nil; l = l.Next {
 			v = l.N
 			if v.Op == OXXX {
 				continue
@@ -390,11 +360,14 @@
 		xfunc.Type = f.Type // update type of ODCLFUNC
 	} else {
 		// The closure is not called, so it is going to stay as closure.
-		nvar = 0
+		nvar := 0
 
-		body = nil
-		offset = int64(Widthptr)
-		for l = func_.Cvars; l != nil; l = l.Next {
+		body := (*NodeList)(nil)
+		offset := int64(Widthptr)
+		var addr *Node
+		var v *Node
+		var cv *Node
+		for l := func_.Cvars; l != nil; l = l.Next {
 			v = l.N
 			if v.Op == OXXX {
 				continue
@@ -450,12 +423,6 @@
 }
 
 func walkclosure(func_ *Node, init **NodeList) *Node {
-	var clos *Node
-	var typ *Node
-	var typ1 *Node
-	var v *Node
-	var l *NodeList
-
 	// If no closure vars, don't bother wrapping.
 	if func_.Cvars == nil {
 		return func_.Closure.Nname
@@ -475,10 +442,12 @@
 	// the struct is unnamed so that closures in multiple packages with the
 	// same struct type can share the descriptor.
 
-	typ = Nod(OTSTRUCT, nil, nil)
+	typ := Nod(OTSTRUCT, nil, nil)
 
 	typ.List = list1(Nod(ODCLFIELD, newname(Lookup(".F")), typenod(Types[TUINTPTR])))
-	for l = func_.Cvars; l != nil; l = l.Next {
+	var typ1 *Node
+	var v *Node
+	for l := func_.Cvars; l != nil; l = l.Next {
 		v = l.N
 		if v.Op == OXXX {
 			continue
@@ -490,7 +459,7 @@
 		typ.List = list(typ.List, Nod(ODCLFIELD, newname(v.Sym), typ1))
 	}
 
-	clos = Nod(OCOMPLIT, nil, Nod(OIND, typ, nil))
+	clos := Nod(OCOMPLIT, nil, Nod(OIND, typ, nil))
 	clos.Esc = func_.Esc
 	clos.Right.Implicit = 1
 	clos.List = concat(list1(Nod(OCFUNC, func_.Closure.Nname, nil)), func_.Enter)
@@ -541,34 +510,15 @@
 var makepartialcall_gopkg *Pkg
 
 func makepartialcall(fn *Node, t0 *Type, meth *Node) *Node {
-	var ptr *Node
-	var n *Node
-	var fld *Node
-	var call *Node
-	var xtype *Node
-	var xfunc *Node
-	var cv *Node
-	var savecurfn *Node
-	var rcvrtype *Type
-	var basetype *Type
-	var t *Type
-	var body *NodeList
-	var l *NodeList
-	var callargs *NodeList
-	var retargs *NodeList
 	var p string
-	var sym *Sym
-	var spkg *Pkg
-	var i int
-	var ddd int
 
-	rcvrtype = fn.Left.Type
+	rcvrtype := fn.Left.Type
 	if exportname(meth.Sym.Name) {
 		p = fmt.Sprintf("(%v).%s-fm", Tconv(rcvrtype, obj.FmtLeft|obj.FmtShort), meth.Sym.Name)
 	} else {
 		p = fmt.Sprintf("(%v).(%v)-fm", Tconv(rcvrtype, obj.FmtLeft|obj.FmtShort), Sconv(meth.Sym, obj.FmtLeft))
 	}
-	basetype = rcvrtype
+	basetype := rcvrtype
 	if Isptr[rcvrtype.Etype] != 0 {
 		basetype = basetype.Type
 	}
@@ -576,7 +526,7 @@
 		Fatal("missing base type for %v", Tconv(rcvrtype, 0))
 	}
 
-	spkg = nil
+	spkg := (*Pkg)(nil)
 	if basetype.Sym != nil {
 		spkg = basetype.Sym.Pkg
 	}
@@ -587,24 +537,26 @@
 		spkg = makepartialcall_gopkg
 	}
 
-	sym = Pkglookup(p, spkg)
+	sym := Pkglookup(p, spkg)
 
 	if sym.Flags&SymUniq != 0 {
 		return sym.Def
 	}
 	sym.Flags |= SymUniq
 
-	savecurfn = Curfn
+	savecurfn := Curfn
 	Curfn = nil
 
-	xtype = Nod(OTFUNC, nil, nil)
-	i = 0
-	l = nil
-	callargs = nil
-	ddd = 0
-	xfunc = Nod(ODCLFUNC, nil, nil)
+	xtype := Nod(OTFUNC, nil, nil)
+	i := 0
+	l := (*NodeList)(nil)
+	callargs := (*NodeList)(nil)
+	ddd := 0
+	xfunc := Nod(ODCLFUNC, nil, nil)
 	Curfn = xfunc
-	for t = getinargx(t0).Type; t != nil; t = t.Down {
+	var fld *Node
+	var n *Node
+	for t := getinargx(t0).Type; t != nil; t = t.Down {
 		namebuf = fmt.Sprintf("a%d", i)
 		i++
 		n = newname(Lookup(namebuf))
@@ -623,8 +575,8 @@
 	xtype.List = l
 	i = 0
 	l = nil
-	retargs = nil
-	for t = getoutargx(t0).Type; t != nil; t = t.Down {
+	retargs := (*NodeList)(nil)
+	for t := getoutargx(t0).Type; t != nil; t = t.Down {
 		namebuf = fmt.Sprintf("r%d", i)
 		i++
 		n = newname(Lookup(namebuf))
@@ -644,16 +596,16 @@
 	declare(xfunc.Nname, PFUNC)
 
 	// Declare and initialize variable holding receiver.
-	body = nil
+	body := (*NodeList)(nil)
 
 	xfunc.Needctxt = true
-	cv = Nod(OCLOSUREVAR, nil, nil)
+	cv := Nod(OCLOSUREVAR, nil, nil)
 	cv.Xoffset = int64(Widthptr)
 	cv.Type = rcvrtype
 	if int(cv.Type.Align) > Widthptr {
 		cv.Xoffset = int64(cv.Type.Align)
 	}
-	ptr = Nod(ONAME, nil, nil)
+	ptr := Nod(ONAME, nil, nil)
 	ptr.Sym = Lookup("rcvr")
 	ptr.Class = PAUTO
 	ptr.Addable = 1
@@ -669,13 +621,13 @@
 		body = list(body, Nod(OAS, ptr, Nod(OADDR, cv, nil)))
 	}
 
-	call = Nod(OCALL, Nod(OXDOT, ptr, meth), nil)
+	call := Nod(OCALL, Nod(OXDOT, ptr, meth), nil)
 	call.List = callargs
 	call.Isddd = uint8(ddd)
 	if t0.Outtuple == 0 {
 		body = list(body, call)
 	} else {
-		n = Nod(OAS2, nil, nil)
+		n := Nod(OAS2, nil, nil)
 		n.List = retargs
 		n.Rlist = list1(call)
 		body = list(body, n)
@@ -694,9 +646,6 @@
 }
 
 func walkpartialcall(n *Node, init **NodeList) *Node {
-	var clos *Node
-	var typ *Node
-
 	// Create closure in the form of a composite literal.
 	// For x.M with receiver (x) type T, the generated code looks like:
 	//
@@ -712,11 +661,11 @@
 		checknil(n.Left, init)
 	}
 
-	typ = Nod(OTSTRUCT, nil, nil)
+	typ := Nod(OTSTRUCT, nil, nil)
 	typ.List = list1(Nod(ODCLFIELD, newname(Lookup("F")), typenod(Types[TUINTPTR])))
 	typ.List = list(typ.List, Nod(ODCLFIELD, newname(Lookup("R")), typenod(n.Left.Type)))
 
-	clos = Nod(OCOMPLIT, nil, Nod(OIND, typ, nil))
+	clos := Nod(OCOMPLIT, nil, Nod(OIND, typ, nil))
 	clos.Esc = n.Esc
 	clos.Right.Implicit = 1
 	clos.List = list1(Nod(OCFUNC, n.Nname.Nname, nil))
diff --git a/src/cmd/internal/gc/const.go b/src/cmd/internal/gc/const.go
index 49d3bcc..43c8809 100644
--- a/src/cmd/internal/gc/const.go
+++ b/src/cmd/internal/gc/const.go
@@ -11,31 +11,27 @@
  * according to type; return truncated value.
  */
 func truncfltlit(oldv *Mpflt, t *Type) *Mpflt {
-	var d float64
-	var fv *Mpflt
-	var v Val
-
 	if t == nil {
 		return oldv
 	}
 
-	v = Val{}
+	v := Val{}
 	v.Ctype = CTFLT
 	v.U.Fval = oldv
 	overflow(v, t)
 
-	fv = new(Mpflt)
+	fv := new(Mpflt)
 	*fv = *oldv
 
 	// convert large precision literal floating
 	// into limited precision (float64 or float32)
 	switch t.Etype {
 	case TFLOAT64:
-		d = mpgetflt(fv)
+		d := mpgetflt(fv)
 		Mpmovecflt(fv, d)
 
 	case TFLOAT32:
-		d = mpgetflt32(fv)
+		d := mpgetflt32(fv)
 		Mpmovecflt(fv, d)
 	}
 
@@ -56,12 +52,7 @@
  * (if n is a named constant, can't edit n->type directly).
  */
 func convlit1(np **Node, t *Type, explicit bool) {
-	var ct int
-	var et int
-	var n *Node
-	var nn *Node
-
-	n = *np
+	n := *np
 	if n == nil || t == nil || n.Type == nil || isideal(t) || n.Type == t {
 		return
 	}
@@ -70,7 +61,7 @@
 	}
 
 	if n.Op == OLITERAL {
-		nn = Nod(OXXX, nil, nil)
+		nn := Nod(OXXX, nil, nil)
 		*nn = *n
 		n = nn
 		*np = n
@@ -148,7 +139,8 @@
 		return
 	}
 
-	ct = consttype(n)
+	ct := consttype(n)
+	var et int
 	if ct < 0 {
 		goto bad
 	}
@@ -214,7 +206,7 @@
 		CTRUNE,
 		CTFLT,
 		CTCPLX:
-		ct = int(n.Val.Ctype)
+		ct := int(n.Val.Ctype)
 		if Isint[et] != 0 {
 			switch ct {
 			default:
@@ -285,24 +277,20 @@
 }
 
 func copyval(v Val) Val {
-	var i *Mpint
-	var f *Mpflt
-	var c *Mpcplx
-
 	switch v.Ctype {
 	case CTINT,
 		CTRUNE:
-		i = new(Mpint)
+		i := new(Mpint)
 		mpmovefixfix(i, v.U.Xval)
 		v.U.Xval = i
 
 	case CTFLT:
-		f = new(Mpflt)
+		f := new(Mpflt)
 		mpmovefltflt(f, v.U.Fval)
 		v.U.Fval = f
 
 	case CTCPLX:
-		c = new(Mpcplx)
+		c := new(Mpcplx)
 		mpmovefltflt(&c.Real, &v.U.Cval.Real)
 		mpmovefltflt(&c.Imag, &v.U.Cval.Imag)
 		v.U.Cval = c
@@ -312,19 +300,17 @@
 }
 
 func tocplx(v Val) Val {
-	var c *Mpcplx
-
 	switch v.Ctype {
 	case CTINT,
 		CTRUNE:
-		c = new(Mpcplx)
+		c := new(Mpcplx)
 		Mpmovefixflt(&c.Real, v.U.Xval)
 		Mpmovecflt(&c.Imag, 0.0)
 		v.Ctype = CTCPLX
 		v.U.Cval = c
 
 	case CTFLT:
-		c = new(Mpcplx)
+		c := new(Mpcplx)
 		mpmovefltflt(&c.Real, v.U.Fval)
 		Mpmovecflt(&c.Imag, 0.0)
 		v.Ctype = CTCPLX
@@ -335,18 +321,16 @@
 }
 
 func toflt(v Val) Val {
-	var f *Mpflt
-
 	switch v.Ctype {
 	case CTINT,
 		CTRUNE:
-		f = new(Mpflt)
+		f := new(Mpflt)
 		Mpmovefixflt(f, v.U.Xval)
 		v.Ctype = CTFLT
 		v.U.Fval = f
 
 	case CTCPLX:
-		f = new(Mpflt)
+		f := new(Mpflt)
 		mpmovefltflt(f, &v.U.Cval.Real)
 		if mpcmpfltc(&v.U.Cval.Imag, 0) != 0 {
 			Yyerror("constant %v%vi truncated to real", Fconv(&v.U.Cval.Real, obj.FmtSharp), Fconv(&v.U.Cval.Imag, obj.FmtSharp|obj.FmtSign))
@@ -359,14 +343,12 @@
 }
 
 func toint(v Val) Val {
-	var i *Mpint
-
 	switch v.Ctype {
 	case CTRUNE:
 		v.Ctype = CTINT
 
 	case CTFLT:
-		i = new(Mpint)
+		i := new(Mpint)
 		if mpmovefltfix(i, v.U.Fval) < 0 {
 			Yyerror("constant %v truncated to integer", Fconv(v.U.Fval, obj.FmtSharp))
 		}
@@ -374,7 +356,7 @@
 		v.U.Xval = i
 
 	case CTCPLX:
-		i = new(Mpint)
+		i := new(Mpint)
 		if mpmovefltfix(i, &v.U.Cval.Real) < 0 {
 			Yyerror("constant %v%vi truncated to integer", Fconv(&v.U.Cval.Real, obj.FmtSharp), Fconv(&v.U.Cval.Imag, obj.FmtSharp|obj.FmtSign))
 		}
@@ -444,17 +426,14 @@
 }
 
 func tostr(v Val) Val {
-	var rune_ uint
-	var s *Strlit
-
 	switch v.Ctype {
 	case CTINT,
 		CTRUNE:
 		if Mpcmpfixfix(v.U.Xval, Minintval[TINT]) < 0 || Mpcmpfixfix(v.U.Xval, Maxintval[TINT]) > 0 {
 			Yyerror("overflow in int -> string")
 		}
-		rune_ = uint(Mpgetfix(v.U.Xval))
-		s = &Strlit{S: string(rune_)}
+		rune_ := uint(Mpgetfix(v.U.Xval))
+		s := &Strlit{S: string(rune_)}
 		v = Val{}
 		v.Ctype = CTSTR
 		v.U.Sval = s
@@ -480,9 +459,7 @@
 }
 
 func Isconst(n *Node, ct int) bool {
-	var t int
-
-	t = consttype(n)
+	t := consttype(n)
 
 	// If the caller is asking for CTINT, allow CTRUNE too.
 	// Makes life easier for back ends.
@@ -490,11 +467,9 @@
 }
 
 func saveorig(n *Node) *Node {
-	var n1 *Node
-
 	if n == n.Orig {
 		// duplicate node for n->orig.
-		n1 = Nod(OLITERAL, nil, nil)
+		n1 := Nod(OLITERAL, nil, nil)
 
 		n.Orig = n1
 		*n1 = *n
@@ -507,20 +482,6 @@
  * if n is constant, rewrite as OLITERAL node.
  */
 func evconst(n *Node) {
-	var nl *Node
-	var nr *Node
-	var norig *Node
-	var str *Strlit
-	var wl int
-	var wr int
-	var lno int
-	var et int
-	var v Val
-	var rv Val
-	var b Mpint
-	var l1 *NodeList
-	var l2 *NodeList
-
 	// pick off just the opcodes that can be
 	// constant evaluated.
 	switch n.Op {
@@ -563,7 +524,11 @@
 
 		// merge adjacent constants in the argument list.
 	case OADDSTR:
-		for l1 = n.List; l1 != nil; l1 = l1.Next {
+		var nr *Node
+		var nl *Node
+		var str *Strlit
+		var l2 *NodeList
+		for l1 := n.List; l1 != nil; l1 = l1.Next {
 			if Isconst(l1.N, CTSTR) && l1.Next != nil && Isconst(l1.Next.N, CTSTR) {
 				// merge from l1 up to but not including l2
 				str = new(Strlit)
@@ -585,7 +550,7 @@
 		}
 
 		// fix list end pointer.
-		for l2 = n.List; l2 != nil; l2 = l2.Next {
+		for l2 := n.List; l2 != nil; l2 = l2.Next {
 			n.List.End = l2
 		}
 
@@ -598,19 +563,24 @@
 		return
 	}
 
-	nl = n.Left
+	nl := n.Left
 	if nl == nil || nl.Type == nil {
 		return
 	}
 	if consttype(nl) < 0 {
 		return
 	}
-	wl = int(nl.Type.Etype)
+	wl := int(nl.Type.Etype)
 	if Isint[wl] != 0 || Isfloat[wl] != 0 || Iscomplex[wl] != 0 {
 		wl = TIDEAL
 	}
 
-	nr = n.Right
+	nr := n.Right
+	var rv Val
+	var lno int
+	var wr int
+	var v Val
+	var norig *Node
 	if nr == nil {
 		goto unary
 	}
@@ -1020,13 +990,14 @@
 
 	case OCOM<<16 | CTINT,
 		OCOM<<16 | CTRUNE:
-		et = Txxx
+		et := Txxx
 		if nl.Type != nil {
 			et = int(nl.Type.Etype)
 		}
 
 		// calculate the mask in b
 		// result will be (a ^ mask)
+		var b Mpint
 		switch et {
 		// signed guys change sign
 		default:
@@ -1107,9 +1078,7 @@
 }
 
 func nodlit(v Val) *Node {
-	var n *Node
-
-	n = Nod(OLITERAL, nil, nil)
+	n := Nod(OLITERAL, nil, nil)
 	n.Val = v
 	switch v.Ctype {
 	default:
@@ -1135,14 +1104,11 @@
 }
 
 func nodcplxlit(r Val, i Val) *Node {
-	var n *Node
-	var c *Mpcplx
-
 	r = toflt(r)
 	i = toflt(i)
 
-	c = new(Mpcplx)
-	n = Nod(OLITERAL, nil, nil)
+	c := new(Mpcplx)
+	n := Nod(OLITERAL, nil, nil)
 	n.Type = Types[TIDEAL]
 	n.Val.U.Cval = c
 	n.Val.Ctype = CTCPLX
@@ -1159,9 +1125,6 @@
 // idealkind returns a constant kind like consttype
 // but for an arbitrary "ideal" (untyped constant) expression.
 func idealkind(n *Node) int {
-	var k1 int
-	var k2 int
-
 	if n == nil || !isideal(n.Type) {
 		return CTxxx
 	}
@@ -1186,9 +1149,9 @@
 		OXOR,
 		OOR,
 		OPLUS:
-		k1 = idealkind(n.Left)
+		k1 := idealkind(n.Left)
 
-		k2 = idealkind(n.Right)
+		k2 := idealkind(n.Right)
 		if k1 > k2 {
 			return k1
 		} else {
@@ -1227,26 +1190,21 @@
 }
 
 func defaultlit(np **Node, t *Type) {
-	var lno int
-	var ctype int
-	var n *Node
-	var nn *Node
-	var t1 *Type
-
-	n = *np
+	n := *np
 	if n == nil || !isideal(n.Type) {
 		return
 	}
 
 	if n.Op == OLITERAL {
-		nn = Nod(OXXX, nil, nil)
+		nn := Nod(OXXX, nil, nil)
 		*nn = *n
 		n = nn
 		*np = n
 	}
 
-	lno = int(setlineno(n))
-	ctype = idealkind(n)
+	lno := int(setlineno(n))
+	ctype := idealkind(n)
+	var t1 *Type
 	switch ctype {
 	default:
 		if t != nil {
@@ -1266,7 +1224,7 @@
 		}
 
 		if n.Val.Ctype == CTSTR {
-			t1 = Types[TSTRING]
+			t1 := Types[TSTRING]
 			Convlit(np, t1)
 			break
 		}
@@ -1277,7 +1235,7 @@
 		Fatal("defaultlit: idealkind is CTxxx: %v", Nconv(n, obj.FmtSign))
 
 	case CTBOOL:
-		t1 = Types[TBOOL]
+		t1 := Types[TBOOL]
 		if t != nil && t.Etype == TBOOL {
 			t1 = t
 		}
@@ -1330,13 +1288,8 @@
  * force means must assign concrete (non-ideal) type.
  */
 func defaultlit2(lp **Node, rp **Node, force int) {
-	var l *Node
-	var r *Node
-	var lkind int
-	var rkind int
-
-	l = *lp
-	r = *rp
+	l := *lp
+	r := *rp
 	if l.Type == nil || r.Type == nil {
 		return
 	}
@@ -1358,8 +1311,8 @@
 		Convlit(rp, Types[TBOOL])
 	}
 
-	lkind = idealkind(l)
-	rkind = idealkind(r)
+	lkind := idealkind(l)
+	rkind := idealkind(r)
 	if lkind == CTCPLX || rkind == CTCPLX {
 		Convlit(lp, Types[TCOMPLEX128])
 		Convlit(rp, Types[TCOMPLEX128])
@@ -1473,10 +1426,7 @@
  * for back end.
  */
 func Convconst(con *Node, t *Type, val *Val) {
-	var i int64
-	var tt int
-
-	tt = Simsimtype(t)
+	tt := Simsimtype(t)
 
 	// copy the constant for conversion
 	Nodconst(con, Types[TINT8], 0)
@@ -1487,6 +1437,7 @@
 	if Isint[tt] != 0 {
 		con.Val.Ctype = CTINT
 		con.Val.U.Xval = new(Mpint)
+		var i int64
 		switch val.Ctype {
 		default:
 			Fatal("convconst ctype=%d %v", val.Ctype, Tconv(t, obj.FmtLong))
@@ -1614,9 +1565,6 @@
 // Only called for expressions known to evaluated to compile-time
 // constants.
 func isgoconst(n *Node) bool {
-	var l *Node
-	var t *Type
-
 	if n.Orig != nil {
 		n = n.Orig
 	}
@@ -1661,7 +1609,7 @@
 
 	case OLEN,
 		OCAP:
-		l = n.Left
+		l := n.Left
 		if isgoconst(l) {
 			return true
 		}
@@ -1669,7 +1617,7 @@
 		// Special case: len/cap is constant when applied to array or
 		// pointer to array when the expression does not contain
 		// function calls or channel receive operations.
-		t = l.Type
+		t := l.Type
 
 		if t != nil && Isptr[t.Etype] != 0 {
 			t = t.Type
@@ -1684,7 +1632,7 @@
 		}
 
 	case ONAME:
-		l = n.Sym.Def
+		l := n.Sym.Def
 		if l != nil && l.Op == OLITERAL && n.Val.Ctype != CTNIL {
 			return true
 		}
@@ -1696,7 +1644,7 @@
 
 		// Only constant calls are unsafe.Alignof, Offsetof, and Sizeof.
 	case OCALL:
-		l = n.Left
+		l := n.Left
 
 		for l.Op == OPAREN {
 			l = l.Left
@@ -1714,8 +1662,6 @@
 }
 
 func hascallchan(n *Node) bool {
-	var l *NodeList
-
 	if n == nil {
 		return false
 	}
@@ -1747,12 +1693,12 @@
 		return true
 	}
 
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		if hascallchan(l.N) {
 			return true
 		}
 	}
-	for l = n.Rlist; l != nil; l = l.Next {
+	for l := n.Rlist; l != nil; l = l.Next {
 		if hascallchan(l.N) {
 			return true
 		}
diff --git a/src/cmd/internal/gc/cplx.go b/src/cmd/internal/gc/cplx.go
index 34decd1..c07ba34 100644
--- a/src/cmd/internal/gc/cplx.go
+++ b/src/cmd/internal/gc/cplx.go
@@ -20,14 +20,6 @@
 
 func Complexbool(op int, nl *Node, nr *Node, true_ bool, likely int, to *obj.Prog) {
 	var tnl Node
-	var tnr Node
-	var n1 Node
-	var n2 Node
-	var n3 Node
-	var n4 Node
-	var na Node
-	var nb Node
-	var nc Node
 
 	// make both sides addable in ullman order
 	if nr != nil {
@@ -38,6 +30,7 @@
 		}
 
 		if nr.Addable == 0 {
+			var tnr Node
 			Tempname(&tnr, nr.Type)
 			Thearch.Cgen(nr, &tnr)
 			nr = &tnr
@@ -53,13 +46,19 @@
 	// build tree
 	// real(l) == real(r) && imag(l) == imag(r)
 
+	var n2 Node
+	var n1 Node
 	subnode(&n1, &n2, nl)
 
+	var n3 Node
+	var n4 Node
 	subnode(&n3, &n4, nr)
 
-	na = Node{}
+	na := Node{}
 	na.Op = OANDAND
+	var nb Node
 	na.Left = &nb
+	var nc Node
 	na.Right = &nc
 	na.Type = Types[TBOOL]
 
@@ -84,16 +83,13 @@
 
 // break addable nc-complex into nr-real and ni-imaginary
 func subnode(nr *Node, ni *Node, nc *Node) {
-	var tc int
-	var t *Type
-
 	if nc.Addable == 0 {
 		Fatal("subnode not addable")
 	}
 
-	tc = Simsimtype(nc.Type)
+	tc := Simsimtype(nc.Type)
 	tc = cplxsubtype(tc)
-	t = Types[tc]
+	t := Types[tc]
 
 	if nc.Op == OLITERAL {
 		nodfconst(nr, t, &nc.Val.U.Cval.Real)
@@ -111,9 +107,7 @@
 
 // generate code res = -nl
 func minus(nl *Node, res *Node) {
-	var ra Node
-
-	ra = Node{}
+	ra := Node{}
 	ra.Op = OMINUS
 	ra.Left = nl
 	ra.Type = nl.Type
@@ -146,13 +140,12 @@
 	var n4 Node
 	var n5 Node
 	var n6 Node
-	var ra Node
 
 	subnode(&n1, &n2, nl)
 	subnode(&n3, &n4, nr)
 	subnode(&n5, &n6, res)
 
-	ra = Node{}
+	ra := Node{}
 	ra.Op = uint8(op)
 	ra.Left = &n1
 	ra.Right = &n3
@@ -178,9 +171,6 @@
 	var n4 Node
 	var n5 Node
 	var n6 Node
-	var rm1 Node
-	var rm2 Node
-	var ra Node
 	var tmp Node
 
 	subnode(&n1, &n2, nl)
@@ -189,20 +179,20 @@
 	Tempname(&tmp, n5.Type)
 
 	// real part -> tmp
-	rm1 = Node{}
+	rm1 := Node{}
 
 	rm1.Op = OMUL
 	rm1.Left = &n1
 	rm1.Right = &n3
 	rm1.Type = n1.Type
 
-	rm2 = Node{}
+	rm2 := Node{}
 	rm2.Op = OMUL
 	rm2.Left = &n2
 	rm2.Right = &n4
 	rm2.Type = n2.Type
 
-	ra = Node{}
+	ra := Node{}
 	ra.Op = OSUB
 	ra.Left = &rm1
 	ra.Right = &rm2
@@ -300,14 +290,6 @@
 }
 
 func Complexmove(f *Node, t *Node) {
-	var ft int
-	var tt int
-	var n1 Node
-	var n2 Node
-	var n3 Node
-	var n4 Node
-	var tmp Node
-
 	if Debug['g'] != 0 {
 		Dump("\ncomplexmove-f", f)
 		Dump("complexmove-t", t)
@@ -317,8 +299,8 @@
 		Fatal("complexmove: to not addable")
 	}
 
-	ft = Simsimtype(f.Type)
-	tt = Simsimtype(t.Type)
+	ft := Simsimtype(f.Type)
+	tt := Simsimtype(t.Type)
 	switch uint32(ft)<<16 | uint32(tt) {
 	default:
 		Fatal("complexmove: unknown conversion: %v -> %v\n", Tconv(f.Type, 0), Tconv(t.Type, 0))
@@ -331,12 +313,17 @@
 		TCOMPLEX128<<16 | TCOMPLEX64,
 		TCOMPLEX128<<16 | TCOMPLEX128:
 		if f.Addable == 0 || overlap_cplx(f, t) {
+			var tmp Node
 			Tempname(&tmp, f.Type)
 			Complexmove(f, &tmp)
 			f = &tmp
 		}
 
+		var n1 Node
+		var n2 Node
 		subnode(&n1, &n2, f)
+		var n4 Node
+		var n3 Node
 		subnode(&n3, &n4, t)
 
 		Thearch.Cgen(&n1, &n3)
@@ -345,16 +332,6 @@
 }
 
 func Complexgen(n *Node, res *Node) {
-	var nl *Node
-	var nr *Node
-	var tnl Node
-	var tnr Node
-	var n1 Node
-	var n2 Node
-	var tmp Node
-	var tl int
-	var tr int
-
 	if Debug['g'] != 0 {
 		Dump("\ncomplexgen-n", n)
 		Dump("complexgen-res", res)
@@ -368,7 +345,10 @@
 	switch n.Op {
 	case OCOMPLEX:
 		if res.Addable != 0 {
+			var n1 Node
+			var n2 Node
 			subnode(&n1, &n2, res)
+			var tmp Node
 			Tempname(&tmp, n1.Type)
 			Thearch.Cgen(n.Left, &tmp)
 			Thearch.Cgen(n.Right, &n2)
@@ -378,13 +358,16 @@
 
 	case OREAL,
 		OIMAG:
-		nl = n.Left
+		nl := n.Left
 		if nl.Addable == 0 {
+			var tmp Node
 			Tempname(&tmp, nl.Type)
 			Complexgen(nl, &tmp)
 			nl = &tmp
 		}
 
+		var n1 Node
+		var n2 Node
 		subnode(&n1, &n2, nl)
 		if n.Op == OREAL {
 			Thearch.Cgen(&n1, res)
@@ -396,13 +379,14 @@
 	}
 
 	// perform conversion from n to res
-	tl = Simsimtype(res.Type)
+	tl := Simsimtype(res.Type)
 
 	tl = cplxsubtype(tl)
-	tr = Simsimtype(n.Type)
+	tr := Simsimtype(n.Type)
 	tr = cplxsubtype(tr)
 	if tl != tr {
 		if n.Addable == 0 {
+			var n1 Node
 			Tempname(&n1, n.Type)
 			Complexmove(n, &n1)
 			n = &n1
@@ -413,6 +397,7 @@
 	}
 
 	if res.Addable == 0 {
+		var n1 Node
 		Thearch.Igen(res, &n1, nil)
 		Thearch.Cgen(n, &n1)
 		Thearch.Regfree(&n1)
@@ -437,6 +422,7 @@
 		OCALLFUNC,
 		OCALLMETH,
 		OCALLINTER:
+		var n1 Node
 		Thearch.Igen(n, &n1, res)
 
 		Complexmove(&n1, res)
@@ -454,13 +440,14 @@
 		break
 	}
 
-	nl = n.Left
+	nl := n.Left
 	if nl == nil {
 		return
 	}
-	nr = n.Right
+	nr := n.Right
 
 	// make both sides addable in ullman order
+	var tnl Node
 	if nr != nil {
 		if nl.Ullman > nr.Ullman && nl.Addable == 0 {
 			Tempname(&tnl, nl.Type)
@@ -469,6 +456,7 @@
 		}
 
 		if nr.Addable == 0 {
+			var tnr Node
 			Tempname(&tnr, nr.Type)
 			Thearch.Cgen(nr, &tnr)
 			nr = &tnr
diff --git a/src/cmd/internal/gc/dcl.go b/src/cmd/internal/gc/dcl.go
index 577f7ec..ceececd 100644
--- a/src/cmd/internal/gc/dcl.go
+++ b/src/cmd/internal/gc/dcl.go
@@ -35,9 +35,7 @@
 }
 
 func push() *Sym {
-	var d *Sym
-
-	d = new(Sym)
+	d := new(Sym)
 	d.Lastlineno = lineno
 	d.Link = dclstack
 	dclstack = d
@@ -45,9 +43,7 @@
 }
 
 func pushdcl(s *Sym) *Sym {
-	var d *Sym
-
-	d = push()
+	d := push()
 	dcopy(d, s)
 	if dflag() {
 		fmt.Printf("\t%v push %v %p\n", Ctxt.Line(int(lineno)), Sconv(s, 0), s.Def)
@@ -94,9 +90,7 @@
 }
 
 func markdcl() {
-	var d *Sym
-
-	d = push()
+	d := push()
 	d.Name = "" // used as a mark in fifo
 	d.Block = block
 
@@ -108,11 +102,9 @@
 //		print("markdcl\n");
 func dumpdcl(st string) {
 	var s *Sym
-	var d *Sym
-	var i int
 
-	i = 0
-	for d = dclstack; d != nil; d = d.Link {
+	i := 0
+	for d := dclstack; d != nil; d = d.Link {
 		i++
 		fmt.Printf("    %.2d %p", i, d)
 		if d.Name == "" {
@@ -127,9 +119,7 @@
 }
 
 func testdclstack() {
-	var d *Sym
-
-	for d = dclstack; d != nil; d = d.Link {
+	for d := dclstack; d != nil; d = d.Link {
 		if d.Name == "" {
 			if nerrors != 0 {
 				errorexit()
@@ -141,10 +131,6 @@
 }
 
 func redeclare(s *Sym, where string) {
-	var pkgstr *Strlit
-	var line1 int
-	var line2 int
-
 	if s.Lastlineno == 0 {
 		var tmp *Strlit
 		if s.Origpkg != nil {
@@ -152,11 +138,11 @@
 		} else {
 			tmp = s.Pkg.Path
 		}
-		pkgstr = tmp
+		pkgstr := tmp
 		Yyerror("%v redeclared %s\n"+"\tprevious declaration during import \"%v\"", Sconv(s, 0), where, Zconv(pkgstr, 0))
 	} else {
-		line1 = parserline()
-		line2 = int(s.Lastlineno)
+		line1 := parserline()
+		line2 := int(s.Lastlineno)
 
 		// When an import and a declaration collide in separate files,
 		// present the import as the "redeclared", because the declaration
@@ -180,9 +166,6 @@
 var declare_typegen int
 
 func declare(n *Node, ctxt int) {
-	var s *Sym
-	var gen int
-
 	if ctxt == PDISCARD {
 		return
 	}
@@ -192,7 +175,7 @@
 	}
 
 	n.Lineno = int32(parserline())
-	s = n.Sym
+	s := n.Sym
 
 	// kludgy: typecheckok means we're past parsing.  Eg genwrapper may declare out of package names later.
 	if importpkg == nil && typecheckok == 0 && s.Pkg != localpkg {
@@ -203,7 +186,7 @@
 		Yyerror("cannot declare init - must be func", s)
 	}
 
-	gen = 0
+	gen := 0
 	if ctxt == PEXTERN {
 		externdcl = list(externdcl, n)
 		if dflag() {
@@ -264,20 +247,15 @@
  * new_name_list (type | [type] = expr_list)
  */
 func variter(vl *NodeList, t *Node, el *NodeList) *NodeList {
-	var doexpr bool
-	var v *Node
-	var e *Node
-	var as2 *Node
-	var init *NodeList
-
-	init = nil
-	doexpr = el != nil
+	init := (*NodeList)(nil)
+	doexpr := el != nil
 
 	if count(el) == 1 && count(vl) > 1 {
-		e = el.N
-		as2 = Nod(OAS2, nil, nil)
+		e := el.N
+		as2 := Nod(OAS2, nil, nil)
 		as2.List = vl
 		as2.Rlist = list1(e)
+		var v *Node
 		for ; vl != nil; vl = vl.Next {
 			v = vl.N
 			v.Op = ONAME
@@ -292,6 +270,8 @@
 		return list(init, as2)
 	}
 
+	var v *Node
+	var e *Node
 	for ; vl != nil; vl = vl.Next {
 		if doexpr {
 			if el == nil {
@@ -333,11 +313,7 @@
  * new_name_list [[type] = expr_list]
  */
 func constiter(vl *NodeList, t *Node, cl *NodeList) *NodeList {
-	var v *Node
-	var c *Node
-	var vv *NodeList
-
-	vv = nil
+	vv := (*NodeList)(nil)
 	if cl == nil {
 		if t != nil {
 			Yyerror("const declaration cannot have type without expression")
@@ -351,6 +327,8 @@
 
 	cl = listtreecopy(cl)
 
+	var v *Node
+	var c *Node
 	for ; vl != nil; vl = vl.Next {
 		if cl == nil {
 			Yyerror("missing value in const declaration")
@@ -382,13 +360,11 @@
  * typically for labels or other one-off names.
  */
 func newname(s *Sym) *Node {
-	var n *Node
-
 	if s == nil {
 		Fatal("newname nil")
 	}
 
-	n = Nod(ONAME, nil, nil)
+	n := Nod(ONAME, nil, nil)
 	n.Sym = s
 	n.Type = nil
 	n.Addable = 1
@@ -402,9 +378,7 @@
  * being declared.
  */
 func dclname(s *Sym) *Node {
-	var n *Node
-
-	n = newname(s)
+	n := newname(s)
 	n.Op = ONONAME // caller will correct it
 	return n
 }
@@ -429,10 +403,7 @@
  * generated if no name has been defined.
  */
 func oldname(s *Sym) *Node {
-	var n *Node
-	var c *Node
-
-	n = s.Def
+	n := s.Def
 	if n == nil {
 		// maybe a top-level name will come along
 		// to give this a definition later.
@@ -453,7 +424,7 @@
 		// make x a closure variable unnecessarily.
 		if n.Closure == nil || n.Closure.Funcdepth != Funcdepth {
 			// create new closure var.
-			c = Nod(ONAME, nil, nil)
+			c := Nod(ONAME, nil, nil)
 
 			c.Sym = s
 			c.Class = PPARAMREF
@@ -493,20 +464,16 @@
 }
 
 func colasdefn(left *NodeList, defn *Node) {
-	var nnew int
-	var nerr int
-	var l *NodeList
-	var n *Node
-
-	for l = left; l != nil; l = l.Next {
+	for l := left; l != nil; l = l.Next {
 		if l.N.Sym != nil {
 			l.N.Sym.Flags |= SymUniq
 		}
 	}
 
-	nnew = 0
-	nerr = 0
-	for l = left; l != nil; l = l.Next {
+	nnew := 0
+	nerr := 0
+	var n *Node
+	for l := left; l != nil; l = l.Next {
 		n = l.N
 		if isblank(n) {
 			continue
@@ -543,9 +510,7 @@
 }
 
 func colas(left *NodeList, right *NodeList, lno int32) *Node {
-	var as *Node
-
-	as = Nod(OAS2, nil, nil)
+	as := Nod(OAS2, nil, nil)
 	as.List = left
 	as.Rlist = right
 	as.Colas = 1
@@ -622,11 +587,6 @@
 }
 
 func funcargs(nt *Node) {
-	var n *Node
-	var nn *Node
-	var l *NodeList
-	var gen int
-
 	if nt.Op != OTFUNC {
 		Fatal("funcargs %v", Oconv(int(nt.Op), 0))
 	}
@@ -640,7 +600,7 @@
 	// no n->defn because type checking of func header
 	// will not fill in the types until later
 	if nt.Left != nil {
-		n = nt.Left
+		n := nt.Left
 		if n.Op != ODCLFIELD {
 			Fatal("funcargs receiver %v", Oconv(int(n.Op), 0))
 		}
@@ -655,7 +615,8 @@
 		}
 	}
 
-	for l = nt.List; l != nil; l = l.Next {
+	var n *Node
+	for l := nt.List; l != nil; l = l.Next {
 		n = l.N
 		if n.Op != ODCLFIELD {
 			Fatal("funcargs in %v", Oconv(int(n.Op), 0))
@@ -672,9 +633,10 @@
 	}
 
 	// declare the out arguments.
-	gen = count(nt.List)
+	gen := count(nt.List)
 	var i int = 0
-	for l = nt.Rlist; l != nil; l = l.Next {
+	var nn *Node
+	for l := nt.Rlist; l != nil; l = l.Next {
 		n = l.N
 
 		if n.Op != ODCLFIELD {
@@ -726,15 +688,13 @@
  * used functype directly to parse the function's type.
  */
 func funcargs2(t *Type) {
-	var ft *Type
-	var n *Node
-
 	if t.Etype != TFUNC {
 		Fatal("funcargs2 %v", Tconv(t, 0))
 	}
 
 	if t.Thistuple != 0 {
-		for ft = getthisx(t).Type; ft != nil; ft = ft.Down {
+		var n *Node
+		for ft := getthisx(t).Type; ft != nil; ft = ft.Down {
 			if ft.Nname == nil || ft.Nname.Sym == nil {
 				continue
 			}
@@ -745,7 +705,8 @@
 	}
 
 	if t.Intuple != 0 {
-		for ft = getinargx(t).Type; ft != nil; ft = ft.Down {
+		var n *Node
+		for ft := getinargx(t).Type; ft != nil; ft = ft.Down {
 			if ft.Nname == nil || ft.Nname.Sym == nil {
 				continue
 			}
@@ -756,7 +717,8 @@
 	}
 
 	if t.Outtuple != 0 {
-		for ft = getoutargx(t).Type; ft != nil; ft = ft.Down {
+		var n *Node
+		for ft := getoutargx(t).Type; ft != nil; ft = ft.Down {
 			if ft.Nname == nil || ft.Nname.Sym == nil {
 				continue
 			}
@@ -790,9 +752,7 @@
  * new type being defined with name s.
  */
 func typedcl0(s *Sym) *Node {
-	var n *Node
-
-	n = newname(s)
+	n := newname(s)
 	n.Op = OTYPE
 	declare(n, dclcontext)
 	return n
@@ -833,17 +793,14 @@
 }
 
 func structfield(n *Node) *Type {
-	var f *Type
-	var lno int
-
-	lno = int(lineno)
+	lno := int(lineno)
 	lineno = n.Lineno
 
 	if n.Op != ODCLFIELD {
 		Fatal("structfield: oops %v\n", Nconv(n, 0))
 	}
 
-	f = typ(TFIELD)
+	f := typ(TFIELD)
 	f.Isddd = n.Isddd
 
 	if n.Right != nil {
@@ -890,9 +847,7 @@
 var uniqgen uint32
 
 func checkdupfields(t *Type, what string) {
-	var lno int
-
-	lno = int(lineno)
+	lno := int(lineno)
 
 	for ; t != nil; t = t.Down {
 		if t.Sym != nil && t.Nname != nil && !isblank(t.Nname) {
@@ -913,19 +868,17 @@
  * a type for struct/interface/arglist
  */
 func tostruct(l *NodeList) *Type {
-	var t *Type
 	var f *Type
-	var tp **Type
-	t = typ(TSTRUCT)
+	t := typ(TSTRUCT)
 
-	for tp = &t.Type; l != nil; l = l.Next {
+	for tp := &t.Type; l != nil; l = l.Next {
 		f = structfield(l.N)
 
 		*tp = f
 		tp = &f.Down
 	}
 
-	for f = t.Type; f != nil && t.Broke == 0; f = f.Down {
+	for f := t.Type; f != nil && t.Broke == 0; f = f.Down {
 		if f.Broke != 0 {
 			t.Broke = 1
 		}
@@ -942,14 +895,12 @@
 }
 
 func tofunargs(l *NodeList) *Type {
-	var t *Type
 	var f *Type
-	var tp **Type
 
-	t = typ(TSTRUCT)
+	t := typ(TSTRUCT)
 	t.Funarg = 1
 
-	for tp = &t.Type; l != nil; l = l.Next {
+	for tp := &t.Type; l != nil; l = l.Next {
 		f = structfield(l.N)
 		f.Funarg = 1
 
@@ -962,7 +913,7 @@
 		tp = &f.Down
 	}
 
-	for f = t.Type; f != nil && t.Broke == 0; f = f.Down {
+	for f := t.Type; f != nil && t.Broke == 0; f = f.Down {
 		if f.Broke != 0 {
 			t.Broke = 1
 		}
@@ -972,10 +923,7 @@
 }
 
 func interfacefield(n *Node) *Type {
-	var f *Type
-	var lno int
-
-	lno = int(lineno)
+	lno := int(lineno)
 	lineno = n.Lineno
 
 	if n.Op != ODCLFIELD {
@@ -986,7 +934,7 @@
 		Yyerror("interface method cannot have annotation")
 	}
 
-	f = typ(TFIELD)
+	f := typ(TFIELD)
 	f.Isddd = n.Isddd
 
 	if n.Right != nil {
@@ -1042,14 +990,12 @@
 }
 
 func tointerface(l *NodeList) *Type {
-	var t *Type
 	var f *Type
-	var tp **Type
 	var t1 *Type
 
-	t = typ(TINTER)
+	t := typ(TINTER)
 
-	tp = &t.Type
+	tp := &t.Type
 	for ; l != nil; l = l.Next {
 		f = interfacefield(l.N)
 
@@ -1072,7 +1018,7 @@
 		}
 	}
 
-	for f = t.Type; f != nil && t.Broke == 0; f = f.Down {
+	for f := t.Type; f != nil && t.Broke == 0; f = f.Down {
 		if f.Broke != 0 {
 			t.Broke = 1
 		}
@@ -1087,20 +1033,19 @@
 }
 
 func embedded(s *Sym, pkg *Pkg) *Node {
-	var n *Node
-	var name string
 	const (
 		CenterDot = 0xB7
 	)
 	// Names sometimes have disambiguation junk
 	// appended after a center dot.  Discard it when
 	// making the name for the embedded struct field.
-	name = s.Name
+	name := s.Name
 
 	if i := strings.Index(s.Name, string(CenterDot)); i >= 0 {
 		name = s.Name[:i]
 	}
 
+	var n *Node
 	if exportname(name) {
 		n = newname(Lookup(name))
 	} else if s.Pkg == builtinpkg {
@@ -1127,14 +1072,8 @@
 }
 
 func checkarglist(all *NodeList, input int) *NodeList {
-	var named int
-	var n *Node
-	var t *Node
-	var nextt *Node
-	var l *NodeList
-
-	named = 0
-	for l = all; l != nil; l = l.Next {
+	named := 0
+	for l := all; l != nil; l = l.Next {
 		if l.N.Op == OKEY {
 			named = 1
 			break
@@ -1142,7 +1081,8 @@
 	}
 
 	if named != 0 {
-		n = nil
+		n := (*Node)(nil)
+		var l *NodeList
 		for l = all; l != nil; l = l.Next {
 			n = l.N
 			if n.Op != OKEY && n.Sym == nil {
@@ -1156,8 +1096,10 @@
 		}
 	}
 
-	nextt = nil
-	for l = all; l != nil; l = l.Next {
+	nextt := (*Node)(nil)
+	var t *Node
+	var n *Node
+	for l := all; l != nil; l = l.Next {
 		// can cache result from findtype to avoid
 		// quadratic behavior here, but unlikely to matter.
 		n = l.N
@@ -1220,9 +1162,7 @@
 }
 
 func fakethis() *Node {
-	var n *Node
-
-	n = Nod(ODCLFIELD, nil, typenod(Ptrto(typ(TSTRUCT))))
+	n := Nod(ODCLFIELD, nil, typenod(Ptrto(typ(TSTRUCT))))
 	return n
 }
 
@@ -1233,14 +1173,11 @@
  * (See fakethis above.)
  */
 func isifacemethod(f *Type) bool {
-	var rcvr *Type
-	var t *Type
-
-	rcvr = getthisx(f).Type
+	rcvr := getthisx(f).Type
 	if rcvr.Sym != nil {
 		return false
 	}
-	t = rcvr.Type
+	t := rcvr.Type
 	if Isptr[t.Etype] == 0 {
 		return false
 	}
@@ -1256,13 +1193,9 @@
  * into a type
  */
 func functype(this *Node, in *NodeList, out *NodeList) *Type {
-	var t *Type
-	var rcvr *NodeList
-	var s *Sym
+	t := typ(TFUNC)
 
-	t = typ(TFUNC)
-
-	rcvr = nil
+	rcvr := (*NodeList)(nil)
 	if this != nil {
 		rcvr = list1(this)
 	}
@@ -1286,7 +1219,7 @@
 	t.Intuple = count(in)
 	t.Outnamed = 0
 	if t.Outtuple > 0 && out.N.Left != nil && out.N.Left.Orig != nil {
-		s = out.N.Left.Orig.Sym
+		s := out.N.Left.Orig.Sym
 		if s != nil && (s.Name[0] != '~' || s.Name[1] != 'r') { // ~r%d is the name invented for an unnamed result
 			t.Outnamed = 1
 		}
@@ -1300,11 +1233,10 @@
 func methodsym(nsym *Sym, t0 *Type, iface int) *Sym {
 	var s *Sym
 	var p string
-	var t *Type
 	var suffix string
 	var spkg *Pkg
 
-	t = t0
+	t := t0
 	if t == nil {
 		goto bad
 	}
@@ -1367,9 +1299,7 @@
 }
 
 func methodname(n *Node, t *Type) *Node {
-	var s *Sym
-
-	s = methodsym(n.Sym, t, 0)
+	s := methodsym(n.Sym, t, 0)
 	if s == nil {
 		return n
 	}
@@ -1377,10 +1307,7 @@
 }
 
 func methodname1(n *Node, t *Node) *Node {
-	var star string
-	var p string
-
-	star = ""
+	star := ""
 	if t.Op == OIND {
 		star = "*"
 		t = t.Left
@@ -1390,6 +1317,7 @@
 		return newname(n.Sym)
 	}
 
+	var p string
 	if star != "" {
 		p = fmt.Sprintf("(%s%v).%v", star, Sconv(t.Sym, 0), Sconv(n.Sym, 0))
 	} else {
@@ -1410,25 +1338,20 @@
  * n is fieldname, pa is base type, t is function type
  */
 func addmethod(sf *Sym, t *Type, local bool, nointerface bool) {
-	var f *Type
-	var d *Type
-	var pa *Type
-	var n *Node
-
 	// get field sym
 	if sf == nil {
 		Fatal("no method symbol")
 	}
 
 	// get parent type sym
-	pa = getthisx(t).Type // ptr to this structure
+	pa := getthisx(t).Type // ptr to this structure
 	if pa == nil {
 		Yyerror("missing receiver")
 		return
 	}
 
 	pa = pa.Type
-	f = methtype(pa, 1)
+	f := methtype(pa, 1)
 	if f == nil {
 		t = pa
 		if t == nil { // rely on typecheck having complained before
@@ -1472,7 +1395,7 @@
 
 	pa = f
 	if pa.Etype == TSTRUCT {
-		for f = pa.Type; f != nil; f = f.Down {
+		for f := pa.Type; f != nil; f = f.Down {
 			if f.Sym == sf {
 				Yyerror("type %v has both field and method named %v", Tconv(pa, 0), Sconv(sf, 0))
 				return
@@ -1487,11 +1410,11 @@
 		return
 	}
 
-	n = Nod(ODCLFIELD, newname(sf), nil)
+	n := Nod(ODCLFIELD, newname(sf), nil)
 	n.Type = t
 
-	d = nil // last found
-	for f = pa.Method; f != nil; f = f.Down {
+	d := (*Type)(nil) // last found
+	for f := pa.Method; f != nil; f = f.Down {
 		d = f
 		if f.Etype != TFIELD {
 			Fatal("addmethod: not TFIELD: %v", Tconv(f, obj.FmtLong))
@@ -1549,11 +1472,8 @@
 }
 
 func funcsym(s *Sym) *Sym {
-	var p string
-	var s1 *Sym
-
-	p = fmt.Sprintf("%s·f", s.Name)
-	s1 = Pkglookup(p, s.Pkg)
+	p := fmt.Sprintf("%s·f", s.Name)
+	s1 := Pkglookup(p, s.Pkg)
 
 	if s1.Def == nil {
 		s1.Def = newname(s1)
diff --git a/src/cmd/internal/gc/esc.go b/src/cmd/internal/gc/esc.go
index f4d5b43..697ca677 100644
--- a/src/cmd/internal/gc/esc.go
+++ b/src/cmd/internal/gc/esc.go
@@ -49,30 +49,23 @@
 )
 
 func escapes(all *NodeList) {
-	var l *NodeList
-
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		l.N.Walkgen = 0
 	}
 
 	visitgen = 0
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC && l.N.Curfn == nil {
 			visit(l.N)
 		}
 	}
 
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		l.N.Walkgen = 0
 	}
 }
 
 func visit(n *Node) uint32 {
-	var min uint32
-	var recursive bool
-	var l *NodeList
-	var block *NodeList
-
 	if n.Walkgen > 0 {
 		// already visited
 		return n.Walkgen
@@ -81,9 +74,9 @@
 	visitgen++
 	n.Walkgen = visitgen
 	visitgen++
-	min = visitgen
+	min := visitgen
 
-	l = new(NodeList)
+	l := new(NodeList)
 	l.Next = stack
 	l.N = n
 	stack = l
@@ -95,13 +88,14 @@
 		// If visitcodelist found its way back to n->walkgen, then this
 		// block is a set of mutually recursive functions.
 		// Otherwise it's just a lone function that does not recurse.
-		recursive = min == n.Walkgen
+		recursive := min == n.Walkgen
 
 		// Remove connected component from stack.
 		// Mark walkgen so that future visits return a large number
 		// so as not to affect the caller's min.
-		block = stack
+		block := stack
 
+		var l *NodeList
 		for l = stack; l.N != n; l = l.Next {
 			l.N.Walkgen = ^uint32(0)
 		}
@@ -124,9 +118,6 @@
 }
 
 func visitcode(n *Node, min uint32) uint32 {
-	var fn *Node
-	var m uint32
-
 	if n == nil {
 		return min
 	}
@@ -142,12 +133,12 @@
 	min = visitcodelist(n.Rlist, min)
 
 	if n.Op == OCALLFUNC || n.Op == OCALLMETH {
-		fn = n.Left
+		fn := n.Left
 		if n.Op == OCALLMETH {
 			fn = n.Left.Right.Sym.Def
 		}
 		if fn != nil && fn.Op == ONAME && fn.Class == PFUNC && fn.Defn != nil {
-			m = visit(fn.Defn)
+			m := visit(fn.Defn)
 			if m < min {
 				min = m
 			}
@@ -155,7 +146,7 @@
 	}
 
 	if n.Op == OCLOSURE {
-		m = visit(n.Closure)
+		m := visit(n.Closure)
 		if m < min {
 			min = m
 		}
@@ -205,9 +196,6 @@
 var tags [16]*Strlit
 
 func mktag(mask int) *Strlit {
-	var s *Strlit
-	var buf string
-
 	switch mask & EscMask {
 	case EscNone,
 		EscReturn:
@@ -223,8 +211,8 @@
 		return tags[mask]
 	}
 
-	buf = fmt.Sprintf("esc:0x%x", mask)
-	s = newstrlit(buf)
+	buf := fmt.Sprintf("esc:0x%x", mask)
+	s := newstrlit(buf)
 	if mask < len(tags) {
 		tags[mask] = s
 	}
@@ -232,15 +220,13 @@
 }
 
 func parsetag(note *Strlit) int {
-	var em int
-
 	if note == nil {
 		return EscUnknown
 	}
 	if !strings.HasPrefix(note.S, "esc:") {
 		return EscUnknown
 	}
-	em = atoi(note.S[4:])
+	em := atoi(note.S[4:])
 	if em == 0 {
 		return EscNone
 	}
@@ -248,12 +234,8 @@
 }
 
 func analyze(all *NodeList, recursive bool) {
-	var l *NodeList
-	var es EscState
-	var e *EscState
-
-	es = EscState{}
-	e = &es
+	es := EscState{}
+	e := &es
 	e.theSink.Op = ONAME
 	e.theSink.Orig = &e.theSink
 	e.theSink.Class = PEXTERN
@@ -267,14 +249,14 @@
 	e.funcParam.Sym = Lookup(".param")
 	e.funcParam.Escloopdepth = 10000000
 
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC {
 			l.N.Esc = EscFuncPlanned
 		}
 	}
 
 	// flow-analyze functions
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC {
 			escfunc(e, l.N)
 		}
@@ -284,19 +266,19 @@
 
 	// visit the upstream of each dst, mark address nodes with
 	// addrescapes, mark parameters unsafe
-	for l = e.dsts; l != nil; l = l.Next {
+	for l := e.dsts; l != nil; l = l.Next {
 		escflood(e, l.N)
 	}
 
 	// for all top level functions, tag the typenodes corresponding to the param nodes
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC {
 			esctag(e, l.N)
 		}
 	}
 
 	if Debug['m'] != 0 {
-		for l = e.noesc; l != nil; l = l.Next {
+		for l := e.noesc; l != nil; l = l.Next {
 			if l.N.Esc == EscNone {
 				var tmp *Sym
 				if l.N.Curfn != nil && l.N.Curfn.Nname != nil {
@@ -311,10 +293,6 @@
 }
 
 func escfunc(e *EscState, func_ *Node) {
-	var savefn *Node
-	var ll *NodeList
-	var saveld int
-
 	//	print("escfunc %N %s\n", func->nname, e->recursive?"(recursive)":"");
 
 	if func_.Esc != 1 {
@@ -322,12 +300,12 @@
 	}
 	func_.Esc = EscFuncStarted
 
-	saveld = e.loopdepth
+	saveld := e.loopdepth
 	e.loopdepth = 1
-	savefn = Curfn
+	savefn := Curfn
 	Curfn = func_
 
-	for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
+	for ll := Curfn.Dcl; ll != nil; ll = ll.Next {
 		if ll.N.Op != ONAME {
 			continue
 		}
@@ -352,7 +330,7 @@
 
 	// in a mutually recursive group we lose track of the return values
 	if e.recursive {
-		for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
+		for ll := Curfn.Dcl; ll != nil; ll = ll.Next {
 			if ll.N.Op == ONAME && ll.N.Class == PPARAMOUT {
 				escflows(e, &e.theSink, ll.N)
 			}
@@ -426,17 +404,14 @@
 }
 
 func esc(e *EscState, n *Node, up *Node) {
-	var lno int
 	var ll *NodeList
 	var lr *NodeList
-	var a *Node
-	var v *Node
 
 	if n == nil {
 		return
 	}
 
-	lno = int(setlineno(n))
+	lno := int(setlineno(n))
 
 	// ninit logically runs at a different loopdepth than the rest of the for loop.
 	esclist(e, n.Ninit, n)
@@ -702,6 +677,8 @@
 
 		// Link addresses of captured variables to closure.
 	case OCLOSURE:
+		var a *Node
+		var v *Node
 		for ll = n.Cvars; ll != nil; ll = ll.Next {
 			v = ll.N
 			if v.Op == OXXX { // unnamed out argument; see dcl.c:/^funcargs
@@ -780,9 +757,6 @@
 // evaluated in curfn.	For expr==nil, dst must still be examined for
 // evaluations inside it (e.g *f(x) = y)
 func escassign(e *EscState, dst *Node, src *Node) {
-	var lno int
-	var ll *NodeList
-
 	if isblank(dst) || dst == nil || src == nil || src.Op == ONONAME || src.Op == OXXX {
 		return
 	}
@@ -846,7 +820,7 @@
 		dst = &e.theSink
 	}
 
-	lno = int(setlineno(src))
+	lno := int(setlineno(src))
 	e.pdepth++
 
 	switch src.Op {
@@ -879,7 +853,7 @@
 	case OCALLMETH,
 		OCALLFUNC,
 		OCALLINTER:
-		for ll = src.Escretval; ll != nil; ll = ll.Next {
+		for ll := src.Escretval; ll != nil; ll = ll.Next {
 			escflows(e, dst, ll.N)
 		}
 
@@ -945,7 +919,6 @@
 
 func escassignfromtag(e *EscState, note *Strlit, dsts *NodeList, src *Node) int {
 	var em int
-	var em0 int
 
 	em = parsetag(note)
 
@@ -964,7 +937,7 @@
 		escassign(e, &e.funcParam, src)
 	}
 
-	em0 = em
+	em0 := em
 	for em >>= EscReturnBits; em != 0 && dsts != nil; (func() { em >>= 1; dsts = dsts.Next })() {
 		if em&1 != 0 {
 			escassign(e, dsts.N, src)
@@ -986,15 +959,9 @@
 func esccall(e *EscState, n *Node, up *Node) {
 	var ll *NodeList
 	var lr *NodeList
-	var a *Node
-	var fn *Node
-	var src *Node
-	var t *Type
 	var fntype *Type
-	var buf string
-	var i int
 
-	fn = nil
+	fn := (*Node)(nil)
 	switch n.Op {
 	default:
 		Fatal("esccall")
@@ -1017,7 +984,7 @@
 
 	ll = n.List
 	if n.List != nil && n.List.Next == nil {
-		a = n.List.N
+		a := n.List.N
 		if a.Type.Etype == TSTRUCT && a.Type.Funarg != 0 { // f(g()).
 			ll = a.Escretval
 		}
@@ -1040,6 +1007,7 @@
 			escassign(e, fn.Ntype.Left.Left, n.Left.Left)
 		}
 
+		var src *Node
 		for lr = fn.Ntype.List; ll != nil && lr != nil; (func() { ll = ll.Next; lr = lr.Next })() {
 			src = ll.N
 			if lr.N.Isddd != 0 && n.Isddd == 0 {
@@ -1079,9 +1047,11 @@
 	}
 
 	// set up out list on this call node with dummy auto ONAMES in the current (calling) function.
-	i = 0
+	i := 0
 
-	for t = getoutargx(fntype).Type; t != nil; t = t.Down {
+	var src *Node
+	var buf string
+	for t := getoutargx(fntype).Type; t != nil; t = t.Down {
 		src = Nod(ONAME, nil, nil)
 		buf = fmt.Sprintf(".dum%d", i)
 		i++
@@ -1099,14 +1069,15 @@
 
 	// Receiver.
 	if n.Op != OCALLFUNC {
-		t = getthisx(fntype).Type
-		src = n.Left.Left
+		t := getthisx(fntype).Type
+		src := n.Left.Left
 		if haspointers(t.Type) {
 			escassignfromtag(e, t.Note, n.Escretval, src)
 		}
 	}
 
-	for t = getinargx(fntype).Type; ll != nil; ll = ll.Next {
+	var a *Node
+	for t := getinargx(fntype).Type; ll != nil; ll = ll.Next {
 		src = ll.N
 		if t.Isddd != 0 && n.Isddd == 0 {
 			// Introduce ODDDARG node to represent ... allocation.
@@ -1197,8 +1168,6 @@
 // Once an object has been moved to the heap, all of it's upstream should be considered
 // escaping to the global scope.
 func escflood(e *EscState, dst *Node) {
-	var l *NodeList
-
 	switch dst.Op {
 	case ONAME,
 		OCLOSURE:
@@ -1218,7 +1187,7 @@
 		fmt.Printf("\nescflood:%d: dst %v scope:%v[%d]\n", walkgen, Nconv(dst, obj.FmtShort), Sconv(tmp, 0), dst.Escloopdepth)
 	}
 
-	for l = dst.Escflowsrc; l != nil; l = l.Next {
+	for l := dst.Escflowsrc; l != nil; l = l.Next {
 		walkgen++
 		escwalk(e, 0, dst, l.N)
 	}
@@ -1240,10 +1209,6 @@
 )
 
 func escwalk(e *EscState, level int, dst *Node, src *Node) {
-	var ll *NodeList
-	var leaks bool
-	var newlevel int
-
 	if src.Walkgen == walkgen && src.Esclevel <= int32(level) {
 		return
 	}
@@ -1263,6 +1228,7 @@
 	e.pdepth++
 
 	// Input parameter flowing to output parameter?
+	var leaks bool
 	if dst.Op == ONAME && dst.Class == PPARAMOUT && dst.Vargen <= 20 {
 		if src.Op == ONAME && src.Class == PPARAM && src.Curfn == dst.Curfn && src.Esc != EscScope && src.Esc != EscHeap {
 			if level == 0 {
@@ -1320,7 +1286,7 @@
 			}
 		}
 
-		newlevel = level
+		newlevel := level
 		if level > MinLevel {
 			newlevel--
 		}
@@ -1373,7 +1339,7 @@
 	case ODOTPTR,
 		OINDEXMAP,
 		OIND:
-		newlevel = level
+		newlevel := level
 
 		if level > MinLevel {
 			newlevel++
@@ -1382,7 +1348,7 @@
 	}
 
 recurse:
-	for ll = src.Escflowsrc; ll != nil; ll = ll.Next {
+	for ll := src.Escflowsrc; ll != nil; ll = ll.Next {
 		escwalk(e, level, dst, ll.N)
 	}
 
@@ -1390,17 +1356,13 @@
 }
 
 func esctag(e *EscState, func_ *Node) {
-	var savefn *Node
-	var ll *NodeList
-	var t *Type
-
 	func_.Esc = EscFuncTagged
 
 	// External functions are assumed unsafe,
 	// unless //go:noescape is given before the declaration.
 	if func_.Nbody == nil {
 		if func_.Noescape {
-			for t = getinargx(func_.Type).Type; t != nil; t = t.Down {
+			for t := getinargx(func_.Type).Type; t != nil; t = t.Down {
 				if haspointers(t.Type) {
 					t.Note = mktag(EscNone)
 				}
@@ -1410,10 +1372,10 @@
 		return
 	}
 
-	savefn = Curfn
+	savefn := Curfn
 	Curfn = func_
 
-	for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
+	for ll := Curfn.Dcl; ll != nil; ll = ll.Next {
 		if ll.N.Op != ONAME || ll.N.Class != PPARAM {
 			continue
 		}
diff --git a/src/cmd/internal/gc/export.go b/src/cmd/internal/gc/export.go
index b0c5931..2467086 100644
--- a/src/cmd/internal/gc/export.go
+++ b/src/cmd/internal/gc/export.go
@@ -79,13 +79,11 @@
 }
 
 func dumppkg(p *Pkg) {
-	var suffix string
-
 	if p == nil || p == localpkg || p.Exported != 0 || p == builtinpkg {
 		return
 	}
 	p.Exported = 1
-	suffix = ""
+	suffix := ""
 	if p.Direct == 0 {
 		suffix = " // indirect"
 	}
@@ -100,8 +98,6 @@
 }
 
 func reexportdep(n *Node) {
-	var t *Type
-
 	if n == nil {
 		return
 	}
@@ -135,7 +131,7 @@
 
 		// Local variables in the bodies need their type.
 	case ODCL:
-		t = n.Left.Type
+		t := n.Left.Type
 
 		if t != Types[t.Etype] && t != idealbool && t != idealstring {
 			if Isptr[t.Etype] != 0 {
@@ -150,7 +146,7 @@
 		}
 
 	case OLITERAL:
-		t = n.Type
+		t := n.Type
 		if t != Types[n.Type.Etype] && t != idealbool && t != idealstring {
 			if Isptr[t.Etype] != 0 {
 				t = t.Type
@@ -190,7 +186,7 @@
 		OMAKEMAP,
 		OMAKESLICE,
 		OMAKECHAN:
-		t = n.Type
+		t := n.Type
 
 		if t.Sym == nil && t.Type != nil {
 			t = t.Type
@@ -215,16 +211,13 @@
 }
 
 func dumpexportconst(s *Sym) {
-	var n *Node
-	var t *Type
-
-	n = s.Def
+	n := s.Def
 	typecheck(&n, Erv)
 	if n == nil || n.Op != OLITERAL {
 		Fatal("dumpexportconst: oconst nil: %v", Sconv(s, 0))
 	}
 
-	t = n.Type // may or may not be specified
+	t := n.Type // may or may not be specified
 	dumpexporttype(t)
 
 	if t != nil && !isideal(t) {
@@ -235,17 +228,14 @@
 }
 
 func dumpexportvar(s *Sym) {
-	var n *Node
-	var t *Type
-
-	n = s.Def
+	n := s.Def
 	typecheck(&n, Erv|Ecall)
 	if n == nil || n.Type == nil {
 		Yyerror("variable exported but not defined: %v", Sconv(s, 0))
 		return
 	}
 
-	t = n.Type
+	t := n.Type
 	dumpexporttype(t)
 
 	if t.Etype == TFUNC && n.Class == PFUNC {
@@ -279,20 +269,12 @@
 }
 
 func (x methodbyname) Less(i, j int) bool {
-	var a *Type
-	var b *Type
-
-	a = x[i]
-	b = x[j]
+	a := x[i]
+	b := x[j]
 	return stringsCompare(a.Sym.Name, b.Sym.Name) < 0
 }
 
 func dumpexporttype(t *Type) {
-	var f *Type
-	var m []*Type
-	var i int
-	var n int
-
 	if t == nil {
 		return
 	}
@@ -312,22 +294,23 @@
 		return
 	}
 
-	n = 0
-	for f = t.Method; f != nil; f = f.Down {
+	n := 0
+	for f := t.Method; f != nil; f = f.Down {
 		dumpexporttype(f)
 		n++
 	}
 
-	m = make([]*Type, n)
-	i = 0
-	for f = t.Method; f != nil; f = f.Down {
+	m := make([]*Type, n)
+	i := 0
+	for f := t.Method; f != nil; f = f.Down {
 		m[i] = f
 		i++
 	}
 	sort.Sort(methodbyname(m[:n]))
 
 	fmt.Fprintf(bout, "\ttype %v %v\n", Sconv(t.Sym, obj.FmtSharp), Tconv(t, obj.FmtSharp|obj.FmtLong))
-	for i = 0; i < n; i++ {
+	var f *Type
+	for i := 0; i < n; i++ {
 		f = m[i]
 		if f.Nointerface {
 			fmt.Fprintf(bout, "\t//go:nointerface\n")
@@ -381,12 +364,7 @@
 }
 
 func dumpexport() {
-	var l *NodeList
-	var i int32
-	var lno int32
-	var p *Pkg
-
-	lno = lineno
+	lno := lineno
 
 	fmt.Fprintf(bout, "\n$$\npackage %s", localpkg.Name)
 	if safemode != 0 {
@@ -394,7 +372,8 @@
 	}
 	fmt.Fprintf(bout, "\n")
 
-	for i = 0; i < int32(len(phash)); i++ {
+	var p *Pkg
+	for i := int32(0); i < int32(len(phash)); i++ {
 		for p = phash[i]; p != nil; p = p.Link {
 			if p.Direct != 0 {
 				dumppkg(p)
@@ -402,7 +381,7 @@
 		}
 	}
 
-	for l = exportlist; l != nil; l = l.Next {
+	for l := exportlist; l != nil; l = l.Next {
 		lineno = l.N.Lineno
 		dumpsym(l.N.Sym)
 	}
@@ -419,10 +398,8 @@
  * return the sym for ss, which should match lexical
  */
 func importsym(s *Sym, op int) *Sym {
-	var pkgstr string
-
 	if s.Def != nil && int(s.Def.Op) != op {
-		pkgstr = fmt.Sprintf("during import \"%v\"", Zconv(importpkg.Path, 0))
+		pkgstr := fmt.Sprintf("during import \"%v\"", Zconv(importpkg.Path, 0))
 		redeclare(s, pkgstr)
 	}
 
@@ -442,11 +419,9 @@
  * return the type pkg.name, forward declaring if needed
  */
 func pkgtype(s *Sym) *Type {
-	var t *Type
-
 	importsym(s, OTYPE)
 	if s.Def == nil || s.Def.Op != OTYPE {
-		t = typ(TFORW)
+		t := typ(TFORW)
 		t.Sym = s
 		s.Def = typenod(t)
 	}
@@ -461,12 +436,11 @@
 	// Informational: record package name
 	// associated with import path, for use in
 	// human-readable messages.
-	var p *Pkg
 
 	if isbadimport(z) {
 		errorexit()
 	}
-	p = mkpkg(z)
+	p := mkpkg(z)
 	if p.Name == "" {
 		p.Name = s.Name
 		Pkglookup(s.Name, nil).Npkg++
@@ -481,8 +455,6 @@
 }
 
 func importconst(s *Sym, t *Type, n *Node) {
-	var n1 *Node
-
 	importsym(s, OLITERAL)
 	Convlit(&n, t)
 
@@ -496,7 +468,7 @@
 	}
 
 	if n.Sym != nil {
-		n1 = Nod(OXXX, nil, nil)
+		n1 := Nod(OXXX, nil, nil)
 		*n1 = *n
 		n = n1
 	}
@@ -511,8 +483,6 @@
 }
 
 func importvar(s *Sym, t *Type) {
-	var n *Node
-
 	importsym(s, ONAME)
 	if s.Def != nil && s.Def.Op == ONAME {
 		if Eqtype(t, s.Def.Type) {
@@ -521,7 +491,7 @@
 		Yyerror("inconsistent definition for var %v during import\n\t%v (in \"%v\")\n\t%v (in \"%v\")", Sconv(s, 0), Tconv(s.Def.Type, 0), Zconv(s.Importdef.Path, 0), Tconv(t, 0), Zconv(importpkg.Path, 0))
 	}
 
-	n = newname(s)
+	n := newname(s)
 	s.Importdef = importpkg
 	n.Type = t
 	declare(n, PEXTERN)
@@ -532,8 +502,6 @@
 }
 
 func importtype(pt *Type, t *Type) {
-	var n *Node
-
 	// override declaration in unsafe.go for Pointer.
 	// there is no way in Go code to define unsafe.Pointer
 	// so we have to supply it.
@@ -542,7 +510,7 @@
 	}
 
 	if pt.Etype == TFORW {
-		n = pt.Nod
+		n := pt.Nod
 		copytype(pt.Nod, t)
 		pt.Nod = n // unzero nod
 		pt.Sym.Importdef = importpkg
@@ -560,16 +528,15 @@
 
 func dumpasmhdr() {
 	var b *obj.Biobuf
-	var l *NodeList
-	var n *Node
-	var t *Type
 
 	b, err := obj.Bopenw(asmhdr)
 	if err != nil {
 		Fatal("%v", err)
 	}
 	fmt.Fprintf(b, "// generated by %cg -asmhdr from package %s\n\n", Thearch.Thechar, localpkg.Name)
-	for l = asmlist; l != nil; l = l.Next {
+	var n *Node
+	var t *Type
+	for l := asmlist; l != nil; l = l.Next {
 		n = l.N
 		if isblanksym(n.Sym) {
 			continue
diff --git a/src/cmd/internal/gc/fmt.go b/src/cmd/internal/gc/fmt.go
index b155f78..ce73676 100644
--- a/src/cmd/internal/gc/fmt.go
+++ b/src/cmd/internal/gc/fmt.go
@@ -88,9 +88,7 @@
 //
 
 func setfmode(flags *int) int {
-	var fm int
-
-	fm = fmtmode
+	fm := fmtmode
 	if *flags&obj.FmtSign != 0 {
 		fmtmode = FDbg
 	} else if *flags&obj.FmtSharp != 0 {
@@ -170,20 +168,21 @@
 
 // Fmt "%O":  Node opcodes
 func Oconv(o int, flag int) string {
-	var fp string
-
 	if (flag&obj.FmtSharp != 0 /*untyped*/) || fmtmode != FDbg {
 		if o >= 0 && o < len(goopnames) && goopnames[o] != "" {
+			var fp string
 			fp += goopnames[o]
 			return fp
 		}
 	}
 
 	if o >= 0 && o < len(opnames) && opnames[o] != "" {
+		var fp string
 		fp += opnames[o]
 		return fp
 	}
 
+	var fp string
 	fp += fmt.Sprintf("O-%d", o)
 	return fp
 }
@@ -202,10 +201,7 @@
 func Jconv(n *Node, flag int) string {
 	var fp string
 
-	var s string
-	var c int
-
-	c = flag & obj.FmtShort
+	c := flag & obj.FmtShort
 
 	if c == 0 && n.Ullman != 0 {
 		fp += fmt.Sprintf(" u(%d)", n.Ullman)
@@ -228,7 +224,7 @@
 	}
 
 	if n.Class != 0 {
-		s = ""
+		s := ""
 		if n.Class&PHEAP != 0 {
 			s = ",heap"
 		}
@@ -309,98 +305,111 @@
 
 // Fmt "%V": Values
 func Vconv(v *Val, flag int) string {
-	var fp string
-
-	var x int64
-
 	switch v.Ctype {
 	case CTINT:
 		if (flag&obj.FmtSharp != 0 /*untyped*/) || fmtmode == FExp {
+			var fp string
 			fp += fmt.Sprintf("%v", Bconv(v.U.Xval, obj.FmtSharp))
 			return fp
 		}
+		var fp string
 		fp += fmt.Sprintf("%v", Bconv(v.U.Xval, 0))
 		return fp
 
 	case CTRUNE:
-		x = Mpgetfix(v.U.Xval)
+		x := Mpgetfix(v.U.Xval)
 		if ' ' <= x && x < 0x80 && x != '\\' && x != '\'' {
+			var fp string
 			fp += fmt.Sprintf("'%c'", int(x))
 			return fp
 		}
 		if 0 <= x && x < 1<<16 {
+			var fp string
 			fp += fmt.Sprintf("'\\u%04x'", uint(int(x)))
 			return fp
 		}
 		if 0 <= x && x <= utf8.MaxRune {
+			var fp string
 			fp += fmt.Sprintf("'\\U%08x'", uint64(x))
 			return fp
 		}
+		var fp string
 		fp += fmt.Sprintf("('\\x00' + %v)", Bconv(v.U.Xval, 0))
 		return fp
 
 	case CTFLT:
 		if (flag&obj.FmtSharp != 0 /*untyped*/) || fmtmode == FExp {
+			var fp string
 			fp += fmt.Sprintf("%v", Fconv(v.U.Fval, 0))
 			return fp
 		}
+		var fp string
 		fp += fmt.Sprintf("%v", Fconv(v.U.Fval, obj.FmtSharp))
 		return fp
 
 	case CTCPLX:
 		if (flag&obj.FmtSharp != 0 /*untyped*/) || fmtmode == FExp {
+			var fp string
 			fp += fmt.Sprintf("(%v+%vi)", Fconv(&v.U.Cval.Real, 0), Fconv(&v.U.Cval.Imag, 0))
 			return fp
 		}
 		if mpcmpfltc(&v.U.Cval.Real, 0) == 0 {
+			var fp string
 			fp += fmt.Sprintf("%vi", Fconv(&v.U.Cval.Imag, obj.FmtSharp))
 			return fp
 		}
 		if mpcmpfltc(&v.U.Cval.Imag, 0) == 0 {
+			var fp string
 			fp += fmt.Sprintf("%v", Fconv(&v.U.Cval.Real, obj.FmtSharp))
 			return fp
 		}
 		if mpcmpfltc(&v.U.Cval.Imag, 0) < 0 {
+			var fp string
 			fp += fmt.Sprintf("(%v%vi)", Fconv(&v.U.Cval.Real, obj.FmtSharp), Fconv(&v.U.Cval.Imag, obj.FmtSharp))
 			return fp
 		}
+		var fp string
 		fp += fmt.Sprintf("(%v+%vi)", Fconv(&v.U.Cval.Real, obj.FmtSharp), Fconv(&v.U.Cval.Imag, obj.FmtSharp))
 		return fp
 
 	case CTSTR:
+		var fp string
 		fp += fmt.Sprintf("\"%v\"", Zconv(v.U.Sval, 0))
 		return fp
 
 	case CTBOOL:
 		if v.U.Bval != 0 {
+			var fp string
 			fp += "true"
 			return fp
 		}
+		var fp string
 		fp += "false"
 		return fp
 
 	case CTNIL:
+		var fp string
 		fp += "nil"
 		return fp
 	}
 
+	var fp string
 	fp += fmt.Sprintf("<ctype=%d>", v.Ctype)
 	return fp
 }
 
 // Fmt "%Z": escaped string literals
 func Zconv(sp *Strlit, flag int) string {
-	var fp string
-	var s string
-	var n int
-
 	if sp == nil {
+		var fp string
 		fp += "<nil>"
 		return fp
 	}
 
 	// NOTE: Keep in sync with ../ld/go.c:/^Zconv.
-	s = sp.S
+	s := sp.S
+	var n int
+	var fp string
 	for i := 0; i < len(s); i += n {
 		var r rune
 		r, n = utf8.DecodeRuneInString(s[i:])
@@ -481,47 +490,49 @@
 
 // Fmt "%E": etype
 func Econv(et int, flag int) string {
-	var fp string
-
 	if et >= 0 && et < len(etnames) && etnames[et] != "" {
+		var fp string
 		fp += etnames[et]
 		return fp
 	}
+	var fp string
 	fp += fmt.Sprintf("E-%d", et)
 	return fp
 }
 
 // Fmt "%S": syms
 func symfmt(s *Sym, flag int) string {
-	var fp string
-
-	var p string
-
 	if s.Pkg != nil && flag&obj.FmtShort == 0 /*untyped*/ {
 		switch fmtmode {
 		case FErr: // This is for the user
 			if s.Pkg == localpkg {
+				var fp string
 				fp += s.Name
 				return fp
 			}
 
 			// If the name was used by multiple packages, display the full path,
 			if s.Pkg.Name != "" && Pkglookup(s.Pkg.Name, nil).Npkg > 1 {
+				var fp string
 				fp += fmt.Sprintf("\"%v\".%s", Zconv(s.Pkg.Path, 0), s.Name)
 				return fp
 			}
+			var fp string
 			fp += fmt.Sprintf("%s.%s", s.Pkg.Name, s.Name)
 			return fp
 
 		case FDbg:
+			var fp string
 			fp += fmt.Sprintf("%s.%s", s.Pkg.Name, s.Name)
 			return fp
 
 		case FTypeId:
 			if flag&obj.FmtUnsigned != 0 /*untyped*/ {
+				var fp string
 				fp += fmt.Sprintf("%s.%s", s.Pkg.Name, s.Name)
 				return fp // dcommontype, typehash
 			}
+			var fp string
 			fp += fmt.Sprintf("%s.%s", s.Pkg.Prefix, s.Name)
 			return fp // (methodsym), typesym, weaksym
 
@@ -530,6 +541,7 @@
 				Fatal("exporting synthetic symbol %s", s.Name)
 			}
 			if s.Pkg != builtinpkg {
+				var fp string
 				fp += fmt.Sprintf("@\"%v\".%s", Zconv(s.Pkg.Path, 0), s.Name)
 				return fp
 			}
@@ -539,21 +551,24 @@
 	if flag&obj.FmtByte != 0 /*untyped*/ { // FmtByte (hh) implies FmtShort (h)
 
 		// skip leading "type." in method name
-		p = s.Name
+		p := s.Name
 		if i := strings.LastIndex(s.Name, "."); i >= 0 {
 			p = s.Name[i+1:]
 		}
 
 		// exportname needs to see the name without the prefix too.
 		if (fmtmode == FExp && !exportname(p)) || fmtmode == FDbg {
+			var fp string
 			fp += fmt.Sprintf("@\"%v\".%s", Zconv(s.Pkg.Path, 0), p)
 			return fp
 		}
 
+		var fp string
 		fp += p
 		return fp
 	}
 
+	var fp string
 	fp += s.Name
 	return fp
 }
@@ -583,12 +598,8 @@
 }
 
 func typefmt(t *Type, flag int) string {
-	var fp string
-
-	var t1 *Type
-	var s *Sym
-
 	if t == nil {
+		var fp string
 		fp += "<T>"
 		return fp
 	}
@@ -596,6 +607,7 @@
 	if t == bytetype || t == runetype {
 		// in %-T mode collapse rune and byte with their originals.
 		if fmtmode != FTypeId {
+			var fp string
 			fp += fmt.Sprintf("%v", Sconv(t.Sym, obj.FmtShort))
 			return fp
 		}
@@ -603,6 +615,7 @@
 	}
 
 	if t == errortype {
+		var fp string
 		fp += "error"
 		return fp
 	}
@@ -613,14 +626,17 @@
 		case FTypeId:
 			if flag&obj.FmtShort != 0 /*untyped*/ {
 				if t.Vargen != 0 {
+					var fp string
 					fp += fmt.Sprintf("%v·%d", Sconv(t.Sym, obj.FmtShort), t.Vargen)
 					return fp
 				}
+				var fp string
 				fp += fmt.Sprintf("%v", Sconv(t.Sym, obj.FmtShort))
 				return fp
 			}
 
 			if flag&obj.FmtUnsigned != 0 /*untyped*/ {
+				var fp string
 				fp += fmt.Sprintf("%v", Sconv(t.Sym, obj.FmtUnsigned))
 				return fp
 			}
@@ -629,15 +645,18 @@
 			// fallthrough
 		case FExp:
 			if t.Sym.Pkg == localpkg && t.Vargen != 0 {
+				var fp string
 				fp += fmt.Sprintf("%v·%d", Sconv(t.Sym, 0), t.Vargen)
 				return fp
 			}
 		}
 
+		var fp string
 		fp += fmt.Sprintf("%v", Sconv(t.Sym, 0))
 		return fp
 	}
 
+	var fp string
 	if int(t.Etype) < len(basicnames) && basicnames[t.Etype] != "" {
 		if fmtmode == FErr && (t == idealbool || t == idealstring) {
 			fp += "untyped "
@@ -696,7 +715,7 @@
 
 	case TINTER:
 		fp += "interface {"
-		for t1 = t.Type; t1 != nil; t1 = t1.Down {
+		for t1 := t.Type; t1 != nil; t1 = t1.Down {
 			if exportname(t1.Sym.Name) {
 				if t1.Down != nil {
 					fp += fmt.Sprintf(" %v%v;", Sconv(t1.Sym, obj.FmtShort), Tconv(t1.Type, obj.FmtShort))
@@ -769,7 +788,7 @@
 		if t.Funarg != 0 {
 			fp += "("
 			if fmtmode == FTypeId || fmtmode == FErr { // no argument names on function signature, and no "noescape"/"nosplit" tags
-				for t1 = t.Type; t1 != nil; t1 = t1.Down {
+				for t1 := t.Type; t1 != nil; t1 = t1.Down {
 					if t1.Down != nil {
 						fp += fmt.Sprintf("%v, ", Tconv(t1, obj.FmtShort))
 					} else {
@@ -777,7 +796,7 @@
 					}
 				}
 			} else {
-				for t1 = t.Type; t1 != nil; t1 = t1.Down {
+				for t1 := t.Type; t1 != nil; t1 = t1.Down {
 					if t1.Down != nil {
 						fp += fmt.Sprintf("%v, ", Tconv(t1, 0))
 					} else {
@@ -789,7 +808,7 @@
 			fp += ")"
 		} else {
 			fp += "struct {"
-			for t1 = t.Type; t1 != nil; t1 = t1.Down {
+			for t1 := t.Type; t1 != nil; t1 = t1.Down {
 				if t1.Down != nil {
 					fp += fmt.Sprintf(" %v;", Tconv(t1, obj.FmtLong))
 				} else {
@@ -803,7 +822,7 @@
 
 	case TFIELD:
 		if flag&obj.FmtShort == 0 /*untyped*/ {
-			s = t.Sym
+			s := t.Sym
 
 			// Take the name from the original, lest we substituted it with ~r%d or ~b%d.
 			// ~r%d is a (formerly) unnamed result.
@@ -896,23 +915,19 @@
 func stmtfmt(n *Node) string {
 	var f string
 
-	var complexinit bool
-	var simpleinit bool
-	var extrablock bool
-
 	// some statements allow for an init, but at most one,
 	// but we may have an arbitrary number added, eg by typecheck
 	// and inlining.  If it doesn't fit the syntax, emit an enclosing
 	// block starting with the init statements.
 
 	// if we can just say "for" n->ninit; ... then do so
-	simpleinit = n.Ninit != nil && n.Ninit.Next == nil && n.Ninit.N.Ninit == nil && stmtwithinit(int(n.Op))
+	simpleinit := n.Ninit != nil && n.Ninit.Next == nil && n.Ninit.N.Ninit == nil && stmtwithinit(int(n.Op))
 
 	// otherwise, print the inits as separate statements
-	complexinit = n.Ninit != nil && !simpleinit && (fmtmode != FErr)
+	complexinit := n.Ninit != nil && !simpleinit && (fmtmode != FErr)
 
 	// but if it was for if/for/switch, put in an extra surrounding block to limit the scope
-	extrablock = complexinit && stmtwithinit(int(n.Op))
+	extrablock := complexinit && stmtwithinit(int(n.Op))
 
 	if extrablock {
 		f += "{"
@@ -1208,50 +1223,51 @@
 }
 
 func exprfmt(n *Node, prec int) string {
-	var f string
-
-	var nprec int
-	var ptrlit bool
-	var l *NodeList
-
 	for n != nil && n.Implicit != 0 && (n.Op == OIND || n.Op == OADDR) {
 		n = n.Left
 	}
 
 	if n == nil {
+		var f string
 		f += "<N>"
 		return f
 	}
 
-	nprec = opprec[n.Op]
+	nprec := opprec[n.Op]
 	if n.Op == OTYPE && n.Sym != nil {
 		nprec = 8
 	}
 
 	if prec > nprec {
+		var f string
 		f += fmt.Sprintf("(%v)", Nconv(n, 0))
 		return f
 	}
 
 	switch n.Op {
 	case OPAREN:
+		var f string
 		f += fmt.Sprintf("(%v)", Nconv(n.Left, 0))
 		return f
 
 	case ODDDARG:
+		var f string
 		f += fmt.Sprintf("... argument")
 		return f
 
 	case OREGISTER:
+		var f string
 		f += fmt.Sprintf("%v", Ctxt.Rconv(int(n.Val.U.Reg)))
 		return f
 
 	case OLITERAL: // this is a bit of a mess
 		if fmtmode == FErr && n.Sym != nil {
+			var f string
 			f += fmt.Sprintf("%v", Sconv(n.Sym, 0))
 			return f
 		}
 		if n.Val.Ctype == CTNIL && n.Orig != nil && n.Orig != n {
+			var f string
 			f += exprfmt(n.Orig, prec)
 			return f
 		}
@@ -1259,14 +1275,17 @@
 			// Need parens when type begins with what might
 			// be misinterpreted as a unary operator: * or <-.
 			if Isptr[n.Type.Etype] != 0 || (n.Type.Etype == TCHAN && n.Type.Chan == Crecv) {
+				var f string
 				f += fmt.Sprintf("(%v)(%v)", Tconv(n.Type, 0), Vconv(&n.Val, 0))
 				return f
 			} else {
+				var f string
 				f += fmt.Sprintf("%v(%v)", Tconv(n.Type, 0), Vconv(&n.Val, 0))
 				return f
 			}
 		}
 
+		var f string
 		f += fmt.Sprintf("%v", Vconv(&n.Val, 0))
 		return f
 
@@ -1274,10 +1293,12 @@
 	// _ becomes ~b%d internally; print as _ for export
 	case ONAME:
 		if fmtmode == FExp && n.Sym != nil && n.Sym.Name[0] == '~' && n.Sym.Name[1] == 'b' {
+			var f string
 			f += fmt.Sprintf("_")
 			return f
 		}
 		if fmtmode == FExp && n.Sym != nil && !isblank(n) && n.Vargen > 0 {
+			var f string
 			f += fmt.Sprintf("%v·%d", Sconv(n.Sym, 0), n.Vargen)
 			return f
 		}
@@ -1287,9 +1308,11 @@
 		// These nodes have the special property that they are names with a left OTYPE and a right ONAME.
 		if fmtmode == FExp && n.Left != nil && n.Left.Op == OTYPE && n.Right != nil && n.Right.Op == ONAME {
 			if Isptr[n.Left.Type.Etype] != 0 {
+				var f string
 				f += fmt.Sprintf("(%v).%v", Tconv(n.Left.Type, 0), Sconv(n.Right.Sym, obj.FmtShort|obj.FmtByte))
 				return f
 			} else {
+				var f string
 				f += fmt.Sprintf("%v.%v", Tconv(n.Left.Type, 0), Sconv(n.Right.Sym, obj.FmtShort|obj.FmtByte))
 				return f
 			}
@@ -1299,44 +1322,54 @@
 		//fallthrough
 	case OPACK,
 		ONONAME:
+		var f string
 		f += fmt.Sprintf("%v", Sconv(n.Sym, 0))
 		return f
 
 	case OTYPE:
 		if n.Type == nil && n.Sym != nil {
+			var f string
 			f += fmt.Sprintf("%v", Sconv(n.Sym, 0))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("%v", Tconv(n.Type, 0))
 		return f
 
 	case OTARRAY:
 		if n.Left != nil {
+			var f string
 			f += fmt.Sprintf("[]%v", Nconv(n.Left, 0))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("[]%v", Nconv(n.Right, 0))
 		return f // happens before typecheck
 
 	case OTMAP:
+		var f string
 		f += fmt.Sprintf("map[%v]%v", Nconv(n.Left, 0), Nconv(n.Right, 0))
 		return f
 
 	case OTCHAN:
 		switch n.Etype {
 		case Crecv:
+			var f string
 			f += fmt.Sprintf("<-chan %v", Nconv(n.Left, 0))
 			return f
 
 		case Csend:
+			var f string
 			f += fmt.Sprintf("chan<- %v", Nconv(n.Left, 0))
 			return f
 
 		default:
 			if n.Left != nil && n.Left.Op == OTCHAN && n.Left.Sym == nil && n.Left.Etype == Crecv {
+				var f string
 				f += fmt.Sprintf("chan (%v)", Nconv(n.Left, 0))
 				return f
 			} else {
+				var f string
 				f += fmt.Sprintf("chan %v", Nconv(n.Left, 0))
 				return f
 			}
@@ -1344,71 +1377,85 @@
 		fallthrough
 
 	case OTSTRUCT:
+		var f string
 		f += fmt.Sprintf("<struct>")
 		return f
 
 	case OTINTER:
+		var f string
 		f += fmt.Sprintf("<inter>")
 		return f
 
 	case OTFUNC:
+		var f string
 		f += fmt.Sprintf("<func>")
 		return f
 
 	case OCLOSURE:
 		if fmtmode == FErr {
+			var f string
 			f += "func literal"
 			return f
 		}
 		if n.Nbody != nil {
+			var f string
 			f += fmt.Sprintf("%v { %v }", Tconv(n.Type, 0), Hconv(n.Nbody, 0))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("%v { %v }", Tconv(n.Type, 0), Hconv(n.Closure.Nbody, 0))
 		return f
 
 	case OCOMPLIT:
-		ptrlit = n.Right != nil && n.Right.Implicit != 0 && n.Right.Type != nil && Isptr[n.Right.Type.Etype] != 0
+		ptrlit := n.Right != nil && n.Right.Implicit != 0 && n.Right.Type != nil && Isptr[n.Right.Type.Etype] != 0
 		if fmtmode == FErr {
 			if n.Right != nil && n.Right.Type != nil && n.Implicit == 0 {
 				if ptrlit {
+					var f string
 					f += fmt.Sprintf("&%v literal", Tconv(n.Right.Type.Type, 0))
 					return f
 				} else {
+					var f string
 					f += fmt.Sprintf("%v literal", Tconv(n.Right.Type, 0))
 					return f
 				}
 			}
 
+			var f string
 			f += "composite literal"
 			return f
 		}
 
 		if fmtmode == FExp && ptrlit {
 			// typecheck has overwritten OIND by OTYPE with pointer type.
+			var f string
 			f += fmt.Sprintf("(&%v{ %v })", Tconv(n.Right.Type.Type, 0), Hconv(n.List, obj.FmtComma))
 			return f
 		}
 
+		var f string
 		f += fmt.Sprintf("(%v{ %v })", Nconv(n.Right, 0), Hconv(n.List, obj.FmtComma))
 		return f
 
 	case OPTRLIT:
 		if fmtmode == FExp && n.Left.Implicit != 0 {
+			var f string
 			f += fmt.Sprintf("%v", Nconv(n.Left, 0))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("&%v", Nconv(n.Left, 0))
 		return f
 
 	case OSTRUCTLIT:
 		if fmtmode == FExp { // requires special handling of field names
+			var f string
 			if n.Implicit != 0 {
 				f += "{"
 			} else {
 				f += fmt.Sprintf("(%v{", Tconv(n.Type, 0))
 			}
-			for l = n.List; l != nil; l = l.Next {
+			for l := n.List; l != nil; l = l.Next {
 				f += fmt.Sprintf(" %v:%v", Sconv(l.N.Left.Sym, obj.FmtShort|obj.FmtByte), Nconv(l.N.Right, 0))
 
 				if l.Next != nil {
@@ -1432,13 +1479,16 @@
 	case OARRAYLIT,
 		OMAPLIT:
 		if fmtmode == FErr {
+			var f string
 			f += fmt.Sprintf("%v literal", Tconv(n.Type, 0))
 			return f
 		}
 		if fmtmode == FExp && n.Implicit != 0 {
+			var f string
 			f += fmt.Sprintf("{ %v }", Hconv(n.List, obj.FmtComma))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("(%v{ %v })", Tconv(n.Type, 0), Hconv(n.List, obj.FmtComma))
 		return f
 
@@ -1446,22 +1496,27 @@
 		if n.Left != nil && n.Right != nil {
 			if fmtmode == FExp && n.Left.Type != nil && n.Left.Type.Etype == TFIELD {
 				// requires special handling of field names
+				var f string
 				f += fmt.Sprintf("%v:%v", Sconv(n.Left.Sym, obj.FmtShort|obj.FmtByte), Nconv(n.Right, 0))
 				return f
 			} else {
+				var f string
 				f += fmt.Sprintf("%v:%v", Nconv(n.Left, 0), Nconv(n.Right, 0))
 				return f
 			}
 		}
 
 		if n.Left == nil && n.Right != nil {
+			var f string
 			f += fmt.Sprintf(":%v", Nconv(n.Right, 0))
 			return f
 		}
 		if n.Left != nil && n.Right == nil {
+			var f string
 			f += fmt.Sprintf("%v:", Nconv(n.Left, 0))
 			return f
 		}
+		var f string
 		f += ":"
 		return f
 
@@ -1471,6 +1526,7 @@
 		ODOTINTER,
 		ODOTMETH,
 		OCALLPART:
+		var f string
 		f += exprfmt(n.Left, nprec)
 		if n.Right == nil || n.Right.Sym == nil {
 			f += ".<nil>"
@@ -1481,6 +1537,7 @@
 
 	case ODOTTYPE,
 		ODOTTYPE2:
+		var f string
 		f += exprfmt(n.Left, nprec)
 		if n.Right != nil {
 			f += fmt.Sprintf(".(%v)", Nconv(n.Right, 0))
@@ -1496,12 +1553,14 @@
 		OSLICEARR,
 		OSLICE3,
 		OSLICE3ARR:
+		var f string
 		f += exprfmt(n.Left, nprec)
 		f += fmt.Sprintf("[%v]", Nconv(n.Right, 0))
 		return f
 
 	case OCOPY,
 		OCOMPLEX:
+		var f string
 		f += fmt.Sprintf("%v(%v, %v)", Oconv(int(n.Op), obj.FmtSharp), Nconv(n.Left, 0), Nconv(n.Right, 0))
 		return f
 
@@ -1514,13 +1573,16 @@
 		OSTRARRAYRUNE,
 		ORUNESTR:
 		if n.Type == nil || n.Type.Sym == nil {
+			var f string
 			f += fmt.Sprintf("(%v)(%v)", Tconv(n.Type, 0), Nconv(n.Left, 0))
 			return f
 		}
 		if n.Left != nil {
+			var f string
 			f += fmt.Sprintf("%v(%v)", Tconv(n.Type, 0), Nconv(n.Left, 0))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("%v(%v)", Tconv(n.Type, 0), Hconv(n.List, obj.FmtComma))
 		return f
 
@@ -1538,13 +1600,16 @@
 		OPRINT,
 		OPRINTN:
 		if n.Left != nil {
+			var f string
 			f += fmt.Sprintf("%v(%v)", Oconv(int(n.Op), obj.FmtSharp), Nconv(n.Left, 0))
 			return f
 		}
 		if n.Isddd != 0 {
+			var f string
 			f += fmt.Sprintf("%v(%v...)", Oconv(int(n.Op), obj.FmtSharp), Hconv(n.List, obj.FmtComma))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("%v(%v)", Oconv(int(n.Op), obj.FmtSharp), Hconv(n.List, obj.FmtComma))
 		return f
 
@@ -1552,6 +1617,7 @@
 		OCALLFUNC,
 		OCALLINTER,
 		OCALLMETH:
+		var f string
 		f += exprfmt(n.Left, nprec)
 		if n.Isddd != 0 {
 			f += fmt.Sprintf("(%v...)", Hconv(n.List, obj.FmtComma))
@@ -1564,17 +1630,21 @@
 		OMAKECHAN,
 		OMAKESLICE:
 		if n.List != nil { // pre-typecheck
+			var f string
 			f += fmt.Sprintf("make(%v, %v)", Tconv(n.Type, 0), Hconv(n.List, obj.FmtComma))
 			return f
 		}
 		if n.Right != nil {
+			var f string
 			f += fmt.Sprintf("make(%v, %v, %v)", Tconv(n.Type, 0), Nconv(n.Left, 0), Nconv(n.Right, 0))
 			return f
 		}
 		if n.Left != nil {
+			var f string
 			f += fmt.Sprintf("make(%v, %v)", Tconv(n.Type, 0), Nconv(n.Left, 0))
 			return f
 		}
+		var f string
 		f += fmt.Sprintf("make(%v)", Tconv(n.Type, 0))
 		return f
 
@@ -1586,6 +1656,7 @@
 		OIND,
 		ONOT,
 		ORECV:
+		var f string
 		if n.Left.Op == n.Op {
 			f += fmt.Sprintf("%v ", Oconv(int(n.Op), obj.FmtSharp))
 		} else {
@@ -1615,6 +1686,7 @@
 		OSEND,
 		OSUB,
 		OXOR:
+		var f string
 		f += exprfmt(n.Left, nprec)
 
 		f += fmt.Sprintf(" %v ", Oconv(int(n.Op), obj.FmtSharp))
@@ -1622,7 +1694,8 @@
 		return f
 
 	case OADDSTR:
-		for l = n.List; l != nil; l = l.Next {
+		var f string
+		for l := n.List; l != nil; l = l.Next {
 			if l != n.List {
 				f += fmt.Sprintf(" + ")
 			}
@@ -1633,22 +1706,20 @@
 
 	case OCMPSTR,
 		OCMPIFACE:
+		var f string
 		f += exprfmt(n.Left, nprec)
 		f += fmt.Sprintf(" %v ", Oconv(int(n.Etype), obj.FmtSharp))
 		f += exprfmt(n.Right, nprec+1)
 		return f
 	}
 
+	var f string
 	f += fmt.Sprintf("<node %v>", Oconv(int(n.Op), 0))
 	return f
 }
 
 func nodefmt(n *Node, flag int) string {
-	var f string
-
-	var t *Type
-
-	t = n.Type
+	t := n.Type
 
 	// we almost always want the original, except in export mode for literals
 	// this saves the importer some work, and avoids us having to redo some
@@ -1659,9 +1730,11 @@
 
 	if flag&obj.FmtLong != 0 /*untyped*/ && t != nil {
 		if t.Etype == TNIL {
+			var f string
 			f += fmt.Sprintf("nil")
 			return f
 		} else {
+			var f string
 			f += fmt.Sprintf("%v (type %v)", Nconv(n, 0), Tconv(t, 0))
 			return f
 		}
@@ -1673,6 +1746,7 @@
 		return stmtfmt(n)
 	}
 
+	var f string
 	f += exprfmt(n, 0)
 	return f
 }
@@ -1684,16 +1758,14 @@
 }
 
 func nodedump(n *Node, flag int) string {
-	var fp string
-
-	var recur bool
-
 	if n == nil {
+		var fp string
 		return fp
 	}
 
-	recur = flag&obj.FmtShort == 0 /*untyped*/
+	recur := flag&obj.FmtShort == 0 /*untyped*/
 
+	var fp string
 	if recur {
 		fp = indent(fp)
 		if dumpdepth > 10 {
@@ -1795,28 +1867,25 @@
 // Fmt "%S": syms
 // Flags:  "%hS" suppresses qualifying with package
 func Sconv(s *Sym, flag int) string {
-	var fp string
-
-	var r int
-	var sm int
-	var sf int
-
 	if flag&obj.FmtLong != 0 /*untyped*/ {
 		panic("linksymfmt")
 	}
 
 	if s == nil {
+		var fp string
 		fp += "<S>"
 		return fp
 	}
 
 	if s.Name == "_" {
+		var fp string
 		fp += "_"
 		return fp
 	}
 
-	sf = flag
-	sm = setfmode(&flag)
+	sf := flag
+	sm := setfmode(&flag)
+	var r int
 	_ = r
 	str := symfmt(s, flag)
 	flag = sf
@@ -1829,25 +1898,21 @@
 //	  'h' omit 'func' and receiver from function types, short type names
 //	  'u' package name, not prefix (FTypeId mode, sticky)
 func Tconv(t *Type, flag int) string {
-	var fp string
-
-	var r int
-	var sm int
-	var sf int
-
 	if t == nil {
+		var fp string
 		fp += "<T>"
 		return fp
 	}
 
 	if t.Trecur > 4 {
+		var fp string
 		fp += "<...>"
 		return fp
 	}
 
 	t.Trecur++
-	sf = flag
-	sm = setfmode(&flag)
+	sf := flag
+	sm := setfmode(&flag)
 
 	if fmtmode == FTypeId && (sf&obj.FmtUnsigned != 0) {
 		fmtpkgpfx++
@@ -1856,6 +1921,7 @@
 		flag |= obj.FmtUnsigned
 	}
 
+	var r int
 	_ = r
 	str := typefmt(t, flag)
 
@@ -1873,19 +1939,15 @@
 // Flags: 'l' suffix with "(type %T)" where possible
 //	  '+h' in debug mode, don't recurse, no multiline output
 func Nconv(n *Node, flag int) string {
-	var fp string
-
-	var r int
-	var sm int
-	var sf int
-
 	if n == nil {
+		var fp string
 		fp += "<N>"
 		return fp
 	}
-	sf = flag
-	sm = setfmode(&flag)
+	sf := flag
+	sm := setfmode(&flag)
 
+	var r int
 	_ = r
 	var str string
 	switch fmtmode {
@@ -1910,28 +1972,24 @@
 // Fmt '%H': NodeList.
 // Flags: all those of %N plus ',': separate with comma's instead of semicolons.
 func Hconv(l *NodeList, flag int) string {
-	var fp string
-
-	var r int
-	var sm int
-	var sf int
-	var sep string
-
 	if l == nil && fmtmode == FDbg {
+		var fp string
 		fp += "<nil>"
 		return fp
 	}
 
-	sf = flag
-	sm = setfmode(&flag)
+	sf := flag
+	sm := setfmode(&flag)
+	var r int
 	_ = r
-	sep = "; "
+	sep := "; "
 	if fmtmode == FDbg {
 		sep = "\n"
 	} else if flag&obj.FmtComma != 0 /*untyped*/ {
 		sep = ", "
 	}
 
+	var fp string
 	for ; l != nil; l = l.Next {
 		fp += fmt.Sprintf("%v", Nconv(l.N, 0))
 		if l.Next != nil {
diff --git a/src/cmd/internal/gc/gen.go b/src/cmd/internal/gc/gen.go
index 9d41b6f..079158a 100644
--- a/src/cmd/internal/gc/gen.go
+++ b/src/cmd/internal/gc/gen.go
@@ -18,9 +18,7 @@
 var lastlabel *Label
 
 func Sysfunc(name string) *Node {
-	var n *Node
-
-	n = newname(Pkglookup(name, Runtimepkg))
+	n := newname(Pkglookup(name, Runtimepkg))
 	n.Class = PFUNC
 	return n
 }
@@ -31,9 +29,6 @@
  * as needing to move to the heap.
  */
 func addrescapes(n *Node) {
-	var buf string
-	var oldfn *Node
-
 	switch n.Op {
 	// probably a type error already.
 	// dump("addrescapes", n);
@@ -84,11 +79,11 @@
 			n.Xoffset = 0
 
 			// create stack variable to hold pointer to heap
-			oldfn = Curfn
+			oldfn := Curfn
 
 			Curfn = n.Curfn
 			n.Heapaddr = temp(Ptrto(n.Type))
-			buf = fmt.Sprintf("&%v", Sconv(n.Sym, 0))
+			buf := fmt.Sprintf("&%v", Sconv(n.Sym, 0))
 			n.Heapaddr.Sym = Lookup(buf)
 			n.Heapaddr.Orig.Sym = n.Heapaddr.Sym
 			n.Esc = EscHeap
@@ -116,9 +111,7 @@
 }
 
 func clearlabels() {
-	var l *Label
-
-	for l = labellist; l != nil; l = l.Link {
+	for l := labellist; l != nil; l = l.Link {
 		l.Sym.Label = nil
 	}
 
@@ -127,11 +120,8 @@
 }
 
 func newlab(n *Node) *Label {
-	var s *Sym
-	var lab *Label
-
-	s = n.Left.Sym
-	lab = s.Label
+	s := n.Left.Sym
+	lab := s.Label
 	if lab == nil {
 		lab = new(Label)
 		if lastlabel == nil {
@@ -158,41 +148,33 @@
 }
 
 func checkgoto(from *Node, to *Node) {
-	var nf int
-	var nt int
-	var block *Sym
-	var dcl *Sym
-	var fs *Sym
-	var ts *Sym
-	var lno int
-
 	if from.Sym == to.Sym {
 		return
 	}
 
-	nf = 0
-	for fs = from.Sym; fs != nil; fs = fs.Link {
+	nf := 0
+	for fs := from.Sym; fs != nil; fs = fs.Link {
 		nf++
 	}
-	nt = 0
-	for fs = to.Sym; fs != nil; fs = fs.Link {
+	nt := 0
+	for fs := to.Sym; fs != nil; fs = fs.Link {
 		nt++
 	}
-	fs = from.Sym
+	fs := from.Sym
 	for ; nf > nt; nf-- {
 		fs = fs.Link
 	}
 	if fs != to.Sym {
-		lno = int(lineno)
+		lno := int(lineno)
 		setlineno(from)
 
 		// decide what to complain about.
 		// prefer to complain about 'into block' over declarations,
 		// so scan backward to find most recent block or else dcl.
-		block = nil
+		block := (*Sym)(nil)
 
-		dcl = nil
-		ts = to.Sym
+		dcl := (*Sym)(nil)
+		ts := to.Sym
 		for ; nt > nf; nt-- {
 			if ts.Pkg == nil {
 				block = ts
@@ -222,10 +204,8 @@
 }
 
 func stmtlabel(n *Node) *Label {
-	var lab *Label
-
 	if n.Sym != nil {
-		lab = n.Sym.Label
+		lab := n.Sym.Label
 		if lab != nil {
 			if lab.Def != nil {
 				if lab.Def.Defn == n {
@@ -295,8 +275,6 @@
  * generate discard of value
  */
 func cgen_discard(nr *Node) {
-	var tmp Node
-
 	if nr == nil {
 		return
 	}
@@ -342,6 +320,7 @@
 
 		// special enough to just evaluate
 	default:
+		var tmp Node
 		Tempname(&tmp, nr.Type)
 
 		Cgen_as(&tmp, nr)
@@ -353,10 +332,7 @@
  * clearslim generates code to zero a slim node.
  */
 func Clearslim(n *Node) {
-	var z Node
-	var zero Mpflt
-
-	z = Node{}
+	z := Node{}
 	z.Op = OLITERAL
 	z.Type = n.Type
 	z.Addable = 1
@@ -370,6 +346,7 @@
 
 	case TFLOAT32,
 		TFLOAT64:
+		var zero Mpflt
 		Mpmovecflt(&zero, 0.0)
 		z.Val.Ctype = CTFLT
 		z.Val.U.Fval = &zero
@@ -410,20 +387,17 @@
  * n->right is data
  */
 func Cgen_eface(n *Node, res *Node) {
-	var dst Node
 	/*
 	 * the right node of an eface may contain function calls that uses res as an argument,
 	 * so it's important that it is done first
 	 */
 
-	var tmp *Node
-
-	tmp = temp(Types[Tptr])
+	tmp := temp(Types[Tptr])
 	Thearch.Cgen(n.Right, tmp)
 
 	Gvardef(res)
 
-	dst = *res
+	dst := *res
 	dst.Type = Types[Tptr]
 	dst.Xoffset += int64(Widthptr)
 	Thearch.Cgen(tmp, &dst)
@@ -442,23 +416,9 @@
  * called for OSLICE, OSLICE3, OSLICEARR, OSLICE3ARR, OSLICESTR.
  */
 func Cgen_slice(n *Node, res *Node) {
-	var src Node
-	var dst Node
-	var cap *Node
-	var len *Node
-	var offs *Node
-	var add *Node
-	var base *Node
-	var tmpcap *Node
-	var tmplen *Node
-	var cmp *Node
-	var con Node
-	var p1 *obj.Prog
-	var p2 *obj.Prog
-
-	cap = n.List.N
-	len = n.List.Next.N
-	offs = nil
+	cap := n.List.N
+	len := n.List.Next.N
+	offs := (*Node)(nil)
 	if n.List.Next.Next != nil {
 		offs = n.List.Next.Next.N
 	}
@@ -470,15 +430,17 @@
 	// might cause preemption or garbage collection.
 	// this makes the whole slice update atomic as far as the
 	// garbage collector can see.
-	base = temp(Types[TUINTPTR])
+	base := temp(Types[TUINTPTR])
 
-	tmplen = temp(Types[TINT])
+	tmplen := temp(Types[TINT])
+	var tmpcap *Node
 	if n.Op != OSLICESTR {
 		tmpcap = temp(Types[TINT])
 	} else {
 		tmpcap = tmplen
 	}
 
+	var src Node
 	if isnil(n.Left) {
 		Tempname(&src, n.Left.Type)
 		Thearch.Cgen(n.Left, &src)
@@ -519,16 +481,17 @@
 	// In essence we are replacing x[i:j:k] where i == j == k
 	// or x[i:j] where i == j == cap(x) with x[0:0:0].
 	if offs != nil {
-		p1 = gjmp(nil)
-		p2 = gjmp(nil)
+		p1 := gjmp(nil)
+		p2 := gjmp(nil)
 		Patch(p1, Pc)
 
+		var con Node
 		Nodconst(&con, tmpcap.Type, 0)
-		cmp = Nod(OEQ, tmpcap, &con)
+		cmp := Nod(OEQ, tmpcap, &con)
 		typecheck(&cmp, Erv)
 		Thearch.Bgen(cmp, true, -1, p2)
 
-		add = Nod(OADD, base, offs)
+		add := Nod(OADD, base, offs)
 		typecheck(&add, Erv)
 		Thearch.Cgen(add, base)
 
@@ -536,7 +499,7 @@
 	}
 
 	// dst.array = src.array  [ + lo *width ]
-	dst = *res
+	dst := *res
 
 	dst.Xoffset += int64(Array_array)
 	dst.Type = Types[Tptr]
@@ -616,9 +579,6 @@
  * make a new off the books
  */
 func Tempname(nn *Node, t *Type) {
-	var n *Node
-	var s *Sym
-
 	if Curfn == nil {
 		Fatal("no curfn for tempname")
 	}
@@ -633,8 +593,8 @@
 	namebuf = fmt.Sprintf("autotmp_%.4d", statuniqgen)
 
 	statuniqgen++
-	s = Lookup(namebuf)
-	n = Nod(ONAME, nil, nil)
+	s := Lookup(namebuf)
+	n := Nod(ONAME, nil, nil)
 	n.Sym = s
 	s.Def = n
 	n.Type = t
@@ -651,26 +611,16 @@
 }
 
 func temp(t *Type) *Node {
-	var n *Node
-
-	n = Nod(OXXX, nil, nil)
+	n := Nod(OXXX, nil, nil)
 	Tempname(n, t)
 	n.Sym.Def.Used = 1
 	return n.Orig
 }
 
 func gen(n *Node) {
-	var lno int32
-	var scontin *obj.Prog
-	var sbreak *obj.Prog
-	var p1 *obj.Prog
-	var p2 *obj.Prog
-	var p3 *obj.Prog
-	var lab *Label
-
 	//dump("gen", n);
 
-	lno = setlineno(n)
+	lno := setlineno(n)
 
 	wasregalloc := Thearch.Anyregalloc()
 
@@ -708,10 +658,11 @@
 			break
 		}
 
-		lab = newlab(n)
+		lab := newlab(n)
 
 		// if there are pending gotos, resolve them all to the current pc.
-		for p1 = lab.Gotopc; p1 != nil; p1 = p2 {
+		var p2 *obj.Prog
+		for p1 := lab.Gotopc; p1 != nil; p1 = p2 {
 			p2 = unpatch(p1)
 			Patch(p1, Pc)
 		}
@@ -739,7 +690,7 @@
 	// to the same label.  we'll unwind it when we learn the pc
 	// of the label in the OLABEL case above.)
 	case OGOTO:
-		lab = newlab(n)
+		lab := newlab(n)
 
 		if lab.Labelpc != nil {
 			gjmp(lab.Labelpc)
@@ -749,7 +700,7 @@
 
 	case OBREAK:
 		if n.Left != nil {
-			lab = n.Left.Sym.Label
+			lab := n.Left.Sym.Label
 			if lab == nil {
 				Yyerror("break label not defined: %v", Sconv(n.Left.Sym, 0))
 				break
@@ -774,7 +725,7 @@
 
 	case OCONTINUE:
 		if n.Left != nil {
-			lab = n.Left.Sym.Label
+			lab := n.Left.Sym.Label
 			if lab == nil {
 				Yyerror("continue label not defined: %v", Sconv(n.Left.Sym, 0))
 				break
@@ -798,14 +749,14 @@
 		gjmp(continpc)
 
 	case OFOR:
-		sbreak = breakpc
-		p1 = gjmp(nil)      //		goto test
+		sbreak := breakpc
+		p1 := gjmp(nil)     //		goto test
 		breakpc = gjmp(nil) // break:	goto done
-		scontin = continpc
+		scontin := continpc
 		continpc = Pc
 
 		// define break and continue labels
-		lab = stmtlabel(n)
+		lab := stmtlabel(n)
 		if lab != nil {
 			lab.Breakpc = breakpc
 			lab.Continpc = continpc
@@ -825,23 +776,23 @@
 		}
 
 	case OIF:
-		p1 = gjmp(nil)                                   //		goto test
-		p2 = gjmp(nil)                                   // p2:		goto else
+		p1 := gjmp(nil)                                  //		goto test
+		p2 := gjmp(nil)                                  // p2:		goto else
 		Patch(p1, Pc)                                    // test:
 		Thearch.Bgen(n.Ntest, false, int(-n.Likely), p2) //		if(!test) goto p2
 		Genlist(n.Nbody)                                 //		then
-		p3 = gjmp(nil)                                   //		goto done
+		p3 := gjmp(nil)                                  //		goto done
 		Patch(p2, Pc)                                    // else:
 		Genlist(n.Nelse)                                 //		else
 		Patch(p3, Pc)                                    // done:
 
 	case OSWITCH:
-		sbreak = breakpc
-		p1 = gjmp(nil)      //		goto test
+		sbreak := breakpc
+		p1 := gjmp(nil)     //		goto test
 		breakpc = gjmp(nil) // break:	goto done
 
 		// define break label
-		lab = stmtlabel(n)
+		lab := stmtlabel(n)
 		if lab != nil {
 			lab.Breakpc = breakpc
 		}
@@ -855,12 +806,12 @@
 		}
 
 	case OSELECT:
-		sbreak = breakpc
-		p1 = gjmp(nil)      //		goto test
+		sbreak := breakpc
+		p1 := gjmp(nil)     //		goto test
 		breakpc = gjmp(nil) // break:	goto done
 
 		// define break label
-		lab = stmtlabel(n)
+		lab := stmtlabel(n)
 		if lab != nil {
 			lab.Breakpc = breakpc
 		}
@@ -918,8 +869,6 @@
 }
 
 func Cgen_as(nl *Node, nr *Node) {
-	var tl *Type
-
 	if Debug['g'] != 0 {
 		Dump("cgen_as", nl)
 		Dump("cgen_as = ", nr)
@@ -940,7 +889,7 @@
 			return
 		}
 
-		tl = nl.Type
+		tl := nl.Type
 		if tl == nil {
 			return
 		}
@@ -956,7 +905,7 @@
 		return
 	}
 
-	tl = nl.Type
+	tl := nl.Type
 	if tl == nil {
 		return
 	}
@@ -965,19 +914,16 @@
 }
 
 func Cgen_callmeth(n *Node, proc int) {
-	var n2 Node
-	var l *Node
-
 	// generate a rewrite in n2 for the method call
 	// (p.f)(...) goes to (f)(p,...)
 
-	l = n.Left
+	l := n.Left
 
 	if l.Op != ODOTMETH {
 		Fatal("cgen_callmeth: not dotmethod: %v")
 	}
 
-	n2 = *n
+	n2 := *n
 	n2.Op = OCALLFUNC
 	n2.Left = l.Right
 	n2.Left.Type = l.Type
@@ -989,10 +935,9 @@
 }
 
 func checklabels() {
-	var lab *Label
 	var l *NodeList
 
-	for lab = labellist; lab != nil; lab = lab.Link {
+	for lab := labellist; lab != nil; lab = lab.Link {
 		if lab.Def == nil {
 			for l = lab.Use; l != nil; l = l.Next {
 				yyerrorl(int(l.N.Lineno), "label %v not defined", Sconv(lab.Sym, 0))
diff --git a/src/cmd/internal/gc/gsubr.go b/src/cmd/internal/gc/gsubr.go
index 6fd6057..ad5e494 100644
--- a/src/cmd/internal/gc/gsubr.go
+++ b/src/cmd/internal/gc/gsubr.go
@@ -80,9 +80,7 @@
  * gsubr.c
  */
 func Gbranch(as int, t *Type, likely int) *obj.Prog {
-	var p *obj.Prog
-
-	p = Prog(as)
+	p := Prog(as)
 	p.To.Type = obj.TYPE_BRANCH
 	p.To.U.Branch = nil
 	if as != obj.AJMP && likely != 0 && Thearch.Thechar != '9' {
@@ -170,9 +168,7 @@
 }
 
 func fixautoused(p *obj.Prog) {
-	var lp **obj.Prog
-
-	for lp = &p; ; {
+	for lp := &p; ; {
 		p = *lp
 		if p == nil {
 			break
@@ -205,9 +201,7 @@
 }
 
 func ggloblnod(nam *Node) {
-	var p *obj.Prog
-
-	p = Thearch.Gins(obj.AGLOBL, nam, nil)
+	p := Thearch.Gins(obj.AGLOBL, nam, nil)
 	p.Lineno = nam.Lineno
 	p.From.Sym.Gotype = Linksym(ngotype(nam))
 	p.To.Sym = nil
@@ -222,9 +216,7 @@
 }
 
 func ggloblsym(s *Sym, width int32, flags int8) {
-	var p *obj.Prog
-
-	p = Thearch.Gins(obj.AGLOBL, nil, nil)
+	p := Thearch.Gins(obj.AGLOBL, nil, nil)
 	p.From.Type = obj.TYPE_MEM
 	p.From.Name = obj.NAME_EXTERN
 	p.From.Sym = Linksym(s)
@@ -234,9 +226,7 @@
 }
 
 func gjmp(to *obj.Prog) *obj.Prog {
-	var p *obj.Prog
-
-	p = Gbranch(obj.AJMP, nil, 0)
+	p := Gbranch(obj.AJMP, nil, 0)
 	if to != nil {
 		Patch(p, to)
 	}
@@ -244,9 +234,7 @@
 }
 
 func gtrack(s *Sym) {
-	var p *obj.Prog
-
-	p = Thearch.Gins(obj.AUSEFIELD, nil, nil)
+	p := Thearch.Gins(obj.AUSEFIELD, nil, nil)
 	p.From.Type = obj.TYPE_MEM
 	p.From.Name = obj.NAME_EXTERN
 	p.From.Sym = Linksym(s)
@@ -287,8 +275,6 @@
 }
 
 func Naddr(n *Node, a *obj.Addr, canemitcode int) {
-	var s *Sym
-
 	*a = obj.Addr{}
 	if n == nil {
 		return
@@ -361,7 +347,7 @@
 			a.Etype = Simtype[n.Type.Etype]
 		}
 		a.Offset = n.Xoffset
-		s = n.Sym
+		s := n.Sym
 		a.Node = n.Orig
 
 		//if(a->node >= (Node*)&n)
@@ -502,9 +488,7 @@
 }
 
 func newplist() *obj.Plist {
-	var pl *obj.Plist
-
-	pl = obj.Linknewplist(Ctxt)
+	pl := obj.Linknewplist(Ctxt)
 
 	Pc = Ctxt.NewProg()
 	Clearp(Pc)
@@ -515,16 +499,14 @@
 
 func nodarg(t *Type, fp int) *Node {
 	var n *Node
-	var l *NodeList
-	var first *Type
-	var savet Iter
 
 	// entire argument struct, not just one arg
 	if t.Etype == TSTRUCT && t.Funarg != 0 {
 		n = Nod(ONAME, nil, nil)
 		n.Sym = Lookup(".args")
 		n.Type = t
-		first = Structfirst(&savet, &t)
+		var savet Iter
+		first := Structfirst(&savet, &t)
 		if first == nil {
 			Fatal("nodarg: bad struct")
 		}
@@ -541,7 +523,8 @@
 	}
 
 	if fp == 1 {
-		for l = Curfn.Dcl; l != nil; l = l.Next {
+		var n *Node
+		for l := Curfn.Dcl; l != nil; l = l.Next {
 			n = l.N
 			if (n.Class == PPARAM || n.Class == PPARAMOUT) && !isblanksym(t.Sym) && n.Sym == t.Sym {
 				return n
@@ -604,12 +587,10 @@
 }
 
 func unpatch(p *obj.Prog) *obj.Prog {
-	var q *obj.Prog
-
 	if p.To.Type != obj.TYPE_BRANCH {
 		Fatal("unpatch: not a branch")
 	}
-	q = p.To.U.Branch
+	q := p.To.U.Branch
 	p.To.U.Branch = nil
 	p.To.Offset = 0
 	return q
diff --git a/src/cmd/internal/gc/init.go b/src/cmd/internal/gc/init.go
index 9202ac5..a7d4fbd 100644
--- a/src/cmd/internal/gc/init.go
+++ b/src/cmd/internal/gc/init.go
@@ -54,12 +54,8 @@
  *	}
  */
 func anyinit(n *NodeList) bool {
-	var h uint32
-	var s *Sym
-	var l *NodeList
-
 	// are there any interesting init statements
-	for l = n; l != nil; l = l.Next {
+	for l := n; l != nil; l = l.Next {
 		switch l.N.Op {
 		case ODCLFUNC,
 			ODCLCONST,
@@ -85,14 +81,14 @@
 	}
 
 	// is there an explicit init function
-	s = Lookup("init.1")
+	s := Lookup("init.1")
 
 	if s.Def != nil {
 		return true
 	}
 
 	// are there any imported init functions
-	for h = 0; h < NHASH; h++ {
+	for h := uint32(0); h < NHASH; h++ {
 		for s = hash[h]; s != nil; s = s.Link {
 			if s.Name[0] != 'i' || s.Name != "init" {
 				continue
@@ -109,16 +105,6 @@
 }
 
 func fninit(n *NodeList) {
-	var i int
-	var gatevar *Node
-	var a *Node
-	var b *Node
-	var fn *Node
-	var r *NodeList
-	var h uint32
-	var s *Sym
-	var initsym *Sym
-
 	if Debug['A'] != 0 {
 		// sys.go or unsafe.go during compiler build
 		return
@@ -129,12 +115,12 @@
 		return
 	}
 
-	r = nil
+	r := (*NodeList)(nil)
 
 	// (1)
 	namebuf = fmt.Sprintf("initdone·")
 
-	gatevar = newname(Lookup(namebuf))
+	gatevar := newname(Lookup(namebuf))
 	addvar(gatevar, Types[TUINT8], PEXTERN)
 
 	// (2)
@@ -142,8 +128,8 @@
 
 	namebuf = fmt.Sprintf("init")
 
-	fn = Nod(ODCLFUNC, nil, nil)
-	initsym = Lookup(namebuf)
+	fn := Nod(ODCLFUNC, nil, nil)
+	initsym := Lookup(namebuf)
 	fn.Nname = newname(initsym)
 	fn.Nname.Defn = fn
 	fn.Nname.Ntype = Nod(OTFUNC, nil, nil)
@@ -151,13 +137,13 @@
 	funchdr(fn)
 
 	// (3)
-	a = Nod(OIF, nil, nil)
+	a := Nod(OIF, nil, nil)
 
 	a.Ntest = Nod(ONE, gatevar, Nodintconst(0))
 	r = list(r, a)
 
 	// (4)
-	b = Nod(OIF, nil, nil)
+	b := Nod(OIF, nil, nil)
 
 	b.Ntest = Nod(OEQ, gatevar, Nodintconst(2))
 	b.Nbody = list1(Nod(ORETURN, nil, nil))
@@ -175,7 +161,8 @@
 	r = list(r, a)
 
 	// (7)
-	for h = 0; h < NHASH; h++ {
+	var s *Sym
+	for h := uint32(0); h < NHASH; h++ {
 		for s = hash[h]; s != nil; s = s.Link {
 			if s.Name[0] != 'i' || s.Name != "init" {
 				continue
@@ -199,7 +186,7 @@
 
 	// (9)
 	// could check that it is fn of no args/returns
-	for i = 1; ; i++ {
+	for i := 1; ; i++ {
 		namebuf = fmt.Sprintf("init.%d", i)
 		s = Lookup(namebuf)
 		if s.Def == nil {
diff --git a/src/cmd/internal/gc/inl.go b/src/cmd/internal/gc/inl.go
index 73d6481..8b088a7 100644
--- a/src/cmd/internal/gc/inl.go
+++ b/src/cmd/internal/gc/inl.go
@@ -47,11 +47,9 @@
 // Get the function's package.  For ordinary functions it's on the ->sym, but for imported methods
 // the ->sym can be re-used in the local package, so peel it off the receiver's type.
 func fnpkg(fn *Node) *Pkg {
-	var rcvr *Type
-
 	if fn.Type.Thistuple != 0 {
 		// method
-		rcvr = getthisx(fn.Type).Type.Type
+		rcvr := getthisx(fn.Type).Type.Type
 
 		if Isptr[rcvr.Etype] != 0 {
 			rcvr = rcvr.Type
@@ -69,18 +67,13 @@
 // Lazy typechecking of imported bodies.  For local functions, caninl will set ->typecheck
 // because they're a copy of an already checked body.
 func typecheckinl(fn *Node) {
-	var savefn *Node
-	var pkg *Pkg
-	var save_safemode int
-	var lno int
-
-	lno = int(setlineno(fn))
+	lno := int(setlineno(fn))
 
 	// typecheckinl is only for imported functions;
 	// their bodies may refer to unsafe as long as the package
 	// was marked safe during import (which was checked then).
 	// the ->inl of a local function has been typechecked before caninl copied it.
-	pkg = fnpkg(fn)
+	pkg := fnpkg(fn)
 
 	if pkg == localpkg || pkg == nil {
 		return // typecheckinl on local function
@@ -90,10 +83,10 @@
 		fmt.Printf("typecheck import [%v] %v { %v }\n", Sconv(fn.Sym, 0), Nconv(fn, obj.FmtLong), Hconv(fn.Inl, obj.FmtSharp))
 	}
 
-	save_safemode = safemode
+	save_safemode := safemode
 	safemode = 0
 
-	savefn = Curfn
+	savefn := Curfn
 	Curfn = fn
 	typechecklist(fn.Inl, Etop)
 	Curfn = savefn
@@ -107,10 +100,6 @@
 // If so, caninl saves fn->nbody in fn->inl and substitutes it with a copy.
 // fn and ->nbody will already have been typechecked.
 func caninl(fn *Node) {
-	var savefn *Node
-	var t *Type
-	var budget int
-
 	if fn.Op != ODCLFUNC {
 		Fatal("caninl %v", Nconv(fn, 0))
 	}
@@ -129,19 +118,19 @@
 
 	// can't handle ... args yet
 	if Debug['l'] < 3 {
-		for t = fn.Type.Type.Down.Down.Type; t != nil; t = t.Down {
+		for t := fn.Type.Type.Down.Down.Type; t != nil; t = t.Down {
 			if t.Isddd != 0 {
 				return
 			}
 		}
 	}
 
-	budget = 40 // allowed hairyness
+	budget := 40 // allowed hairyness
 	if ishairylist(fn.Nbody, &budget) {
 		return
 	}
 
-	savefn = Curfn
+	savefn := Curfn
 	Curfn = fn
 
 	fn.Nname.Inl = fn.Nbody
@@ -211,9 +200,7 @@
 // Any name-like node of non-local class is marked for re-export by adding it to
 // the exportlist.
 func inlcopylist(ll *NodeList) *NodeList {
-	var l *NodeList
-
-	l = nil
+	l := (*NodeList)(nil)
 	for ; ll != nil; ll = ll.Next {
 		l = list(l, inlcopy(ll.N))
 	}
@@ -221,8 +208,6 @@
 }
 
 func inlcopy(n *Node) *Node {
-	var m *Node
-
 	if n == nil {
 		return nil
 	}
@@ -234,7 +219,7 @@
 		return n
 	}
 
-	m = Nod(OXXX, nil, nil)
+	m := Nod(OXXX, nil, nil)
 	*m = *n
 	m.Inl = nil
 	m.Left = inlcopy(n.Left)
@@ -253,9 +238,7 @@
 // Inlcalls/nodelist/node walks fn's statements and expressions and substitutes any
 // calls made to inlineable functions.  This is the external entry point.
 func inlcalls(fn *Node) {
-	var savefn *Node
-
-	savefn = Curfn
+	savefn := Curfn
 	Curfn = fn
 	inlnode(&fn)
 	if fn != Curfn {
@@ -277,10 +260,8 @@
 
 // Turn an OINLCALL into a single valued expression.
 func inlconv2expr(np **Node) {
-	var n *Node
-	var r *Node
-	n = *np
-	r = n.Rlist.N
+	n := *np
+	r := n.Rlist.N
 	addinit(&r, concat(n.Ninit, n.Nbody))
 	*np = r
 }
@@ -291,13 +272,11 @@
 // order will be preserved Used in return, oas2func and call
 // statements.
 func inlconv2list(n *Node) *NodeList {
-	var l *NodeList
-
 	if n.Op != OINLCALL || n.Rlist == nil {
 		Fatal("inlconv2list %v\n", Nconv(n, obj.FmtSign))
 	}
 
-	l = n.Rlist
+	l := n.Rlist
 	addinit(&l.N, concat(n.Ninit, n.Nbody))
 	return l
 }
@@ -320,15 +299,11 @@
 // but then you may as well do it here.  so this is cleaner and
 // shorter and less complicated.
 func inlnode(np **Node) {
-	var n *Node
-	var l *NodeList
-	var lno int
-
 	if *np == nil {
 		return
 	}
 
-	n = *np
+	n := *np
 
 	switch n.Op {
 	// inhibit inlining of their argument
@@ -347,10 +322,10 @@
 		return
 	}
 
-	lno = int(setlineno(n))
+	lno := int(setlineno(n))
 
 	inlnodelist(n.Ninit)
-	for l = n.Ninit; l != nil; l = l.Next {
+	for l := n.Ninit; l != nil; l = l.Next {
 		if l.N.Op == OINLCALL {
 			inlconv2stmt(l.N)
 		}
@@ -369,7 +344,7 @@
 	inlnodelist(n.List)
 	switch n.Op {
 	case OBLOCK:
-		for l = n.List; l != nil; l = l.Next {
+		for l := n.List; l != nil; l = l.Next {
 			if l.N.Op == OINLCALL {
 				inlconv2stmt(l.N)
 			}
@@ -391,7 +366,7 @@
 
 		// fallthrough
 	default:
-		for l = n.List; l != nil; l = l.Next {
+		for l := n.List; l != nil; l = l.Next {
 			if l.N.Op == OINLCALL {
 				inlconv2expr(&l.N)
 			}
@@ -412,7 +387,7 @@
 
 		// fallthrough
 	default:
-		for l = n.Rlist; l != nil; l = l.Next {
+		for l := n.Rlist; l != nil; l = l.Next {
 			if l.N.Op == OINLCALL {
 				inlconv2expr(&l.N)
 			}
@@ -430,14 +405,14 @@
 	}
 
 	inlnodelist(n.Nbody)
-	for l = n.Nbody; l != nil; l = l.Next {
+	for l := n.Nbody; l != nil; l = l.Next {
 		if l.N.Op == OINLCALL {
 			inlconv2stmt(l.N)
 		}
 	}
 
 	inlnodelist(n.Nelse)
-	for l = n.Nelse; l != nil; l = l.Next {
+	for l := n.Nelse; l != nil; l = l.Next {
 		if l.N.Op == OINLCALL {
 			inlconv2stmt(l.N)
 		}
@@ -488,14 +463,11 @@
 }
 
 func mkinlcall(np **Node, fn *Node, isddd int) {
-	var save_safemode int
-	var pkg *Pkg
-
-	save_safemode = safemode
+	save_safemode := safemode
 
 	// imported functions may refer to unsafe as long as the
 	// package was marked safe during import (already checked).
-	pkg = fnpkg(fn)
+	pkg := fnpkg(fn)
 
 	if pkg != localpkg && pkg != nil {
 		safemode = 0
@@ -523,26 +495,6 @@
 // inlined function body and list, rlist contain the input, output
 // parameters.
 func mkinlcall1(np **Node, fn *Node, isddd int) {
-	var i int
-	var chkargcount bool
-	var n *Node
-	var call *Node
-	var saveinlfn *Node
-	var as *Node
-	var m *Node
-	var dcl *NodeList
-	var ll *NodeList
-	var ninit *NodeList
-	var body *NodeList
-	var t *Type
-	var variadic bool
-	var varargcount int
-	var multiret int
-	var vararg *Node
-	var varargs *NodeList
-	var varargtype *Type
-	var vararrtype *Type
-
 	// For variadic fn.
 	if fn.Inl == nil {
 		return
@@ -556,7 +508,7 @@
 		typecheckinl(fn)
 	}
 
-	n = *np
+	n := *np
 
 	// Bingo, we have a function node, and it has an inlineable body
 	if Debug['m'] > 1 {
@@ -569,13 +521,14 @@
 		fmt.Printf("%v: Before inlining: %v\n", n.Line(), Nconv(n, obj.FmtSign))
 	}
 
-	saveinlfn = inlfn
+	saveinlfn := inlfn
 	inlfn = fn
 
-	ninit = n.Ninit
+	ninit := n.Ninit
 
 	//dumplist("ninit pre", ninit);
 
+	var dcl *NodeList
 	if fn.Defn != nil { // local function
 		dcl = fn.Inldcl // imported function
 	} else {
@@ -583,10 +536,10 @@
 	}
 
 	inlretvars = nil
-	i = 0
+	i := 0
 
 	// Make temp names to use instead of the originals
-	for ll = dcl; ll != nil; ll = ll.Next {
+	for ll := dcl; ll != nil; ll = ll.Next {
 		if ll.N.Class == PPARAMOUT { // return values handled below.
 			continue
 		}
@@ -603,7 +556,8 @@
 	}
 
 	// temporaries for return values.
-	for t = getoutargx(fn.Type).Type; t != nil; t = t.Down {
+	var m *Node
+	for t := getoutargx(fn.Type).Type; t != nil; t = t.Down {
 		if t != nil && t.Nname != nil && !isblank(t.Nname) {
 			m = inlvar(t.Nname)
 			typecheck(&m, Erv)
@@ -619,9 +573,10 @@
 	}
 
 	// assign receiver.
+	var as *Node
 	if fn.Type.Thistuple != 0 && n.Left.Op == ODOTMETH {
 		// method call with a receiver.
-		t = getthisx(fn.Type).Type
+		t := getthisx(fn.Type).Type
 
 		if t != nil && t.Nname != nil && !isblank(t.Nname) && t.Nname.Inlvar == nil {
 			Fatal("missing inlvar for %v\n", Nconv(t.Nname, 0))
@@ -640,11 +595,11 @@
 	}
 
 	// check if inlined function is variadic.
-	variadic = false
+	variadic := false
 
-	varargtype = nil
-	varargcount = 0
-	for t = fn.Type.Type.Down.Down.Type; t != nil; t = t.Down {
+	varargtype := (*Type)(nil)
+	varargcount := 0
+	for t := fn.Type.Type.Down.Down.Type; t != nil; t = t.Down {
 		if t.Isddd != 0 {
 			variadic = true
 			varargtype = t.Type
@@ -657,7 +612,7 @@
 	}
 
 	// check if argument is actually a returned tuple from call.
-	multiret = 0
+	multiret := 0
 
 	if n.List != nil && n.List.Next == nil {
 		switch n.List.N.Op {
@@ -683,7 +638,7 @@
 	as = Nod(OAS2, nil, nil)
 
 	as.Rlist = n.List
-	ll = n.List
+	ll := n.List
 
 	// TODO: if len(nlist) == 1 but multiple args, check that n->list->n is a call?
 	if fn.Type.Thistuple != 0 && n.Left.Op != ODOTMETH {
@@ -693,7 +648,7 @@
 		}
 
 		// append receiver inlvar to LHS.
-		t = getthisx(fn.Type).Type
+		t := getthisx(fn.Type).Type
 
 		if t != nil && t.Nname != nil && !isblank(t.Nname) && t.Nname.Inlvar == nil {
 			Fatal("missing inlvar for %v\n", Nconv(t.Nname, 0))
@@ -706,13 +661,14 @@
 	}
 
 	// append ordinary arguments to LHS.
-	chkargcount = n.List != nil && n.List.Next != nil
+	chkargcount := n.List != nil && n.List.Next != nil
 
-	vararg = nil  // the slice argument to a variadic call
-	varargs = nil // the list of LHS names to put in vararg.
+	vararg := (*Node)(nil)      // the slice argument to a variadic call
+	varargs := (*NodeList)(nil) // the list of LHS names to put in vararg.
 	if !chkargcount {
 		// 0 or 1 expression on RHS.
-		for t = getinargx(fn.Type).Type; t != nil; t = t.Down {
+		var i int
+		for t := getinargx(fn.Type).Type; t != nil; t = t.Down {
 			if variadic && t.Isddd != 0 {
 				vararg = tinlvar(t)
 				for i = 0; i < varargcount && ll != nil; i++ {
@@ -728,6 +684,7 @@
 		}
 	} else {
 		// match arguments except final variadic (unless the call is dotted itself)
+		var t *Type
 		for t = getinargx(fn.Type).Type; t != nil; {
 			if ll == nil {
 				break
@@ -743,6 +700,7 @@
 		// match varargcount arguments with variadic parameters.
 		if variadic && t != nil && t.Isddd != 0 {
 			vararg = tinlvar(t)
+			var i int
 			for i = 0; i < varargcount && ll != nil; i++ {
 				m = argvar(varargtype, i)
 				varargs = list(varargs, m)
@@ -772,7 +730,7 @@
 			as.Right = nodnil()
 			as.Right.Type = varargtype
 		} else {
-			vararrtype = typ(TARRAY)
+			vararrtype := typ(TARRAY)
 			vararrtype.Type = varargtype.Type
 			vararrtype.Bound = int64(varargcount)
 
@@ -786,7 +744,7 @@
 	}
 
 	// zero the outparams
-	for ll = inlretvars; ll != nil; ll = ll.Next {
+	for ll := inlretvars; ll != nil; ll = ll.Next {
 		as = Nod(OAS, ll.N, nil)
 		typecheck(&as, Etop)
 		ninit = list(ninit, as)
@@ -794,7 +752,7 @@
 
 	inlretlabel = newlabel_inl()
 	inlgen++
-	body = inlsubstlist(fn.Inl)
+	body := inlsubstlist(fn.Inl)
 
 	body = list(body, Nod(OGOTO, inlretlabel, nil)) // avoid 'not used' when function doesnt have return
 	body = list(body, Nod(OLABEL, inlretlabel, nil))
@@ -803,7 +761,7 @@
 
 	//dumplist("ninit post", ninit);
 
-	call = Nod(OINLCALL, nil, nil)
+	call := Nod(OINLCALL, nil, nil)
 
 	call.Ninit = ninit
 	call.Nbody = body
@@ -824,10 +782,10 @@
 	// either supporting exporting statemetns with complex ninits
 	// or saving inl and making inlinl
 	if Debug['l'] >= 5 {
-		body = fn.Inl
+		body := fn.Inl
 		fn.Inl = nil // prevent infinite recursion
 		inlnodelist(call.Nbody)
-		for ll = call.Nbody; ll != nil; ll = ll.Next {
+		for ll := call.Nbody; ll != nil; ll = ll.Next {
 			if ll.N.Op == OINLCALL {
 				inlconv2stmt(ll.N)
 			}
@@ -844,13 +802,11 @@
 // PAUTO's in the calling functions, and link them off of the
 // PPARAM's, PAUTOS and PPARAMOUTs of the called function.
 func inlvar(var_ *Node) *Node {
-	var n *Node
-
 	if Debug['m'] > 3 {
 		fmt.Printf("inlvar %v\n", Nconv(var_, obj.FmtSign))
 	}
 
-	n = newname(var_.Sym)
+	n := newname(var_.Sym)
 	n.Type = var_.Type
 	n.Class = PAUTO
 	n.Used = 1
@@ -872,10 +828,8 @@
 
 // Synthesize a variable to store the inlined function's results in.
 func retvar(t *Type, i int) *Node {
-	var n *Node
-
 	namebuf = fmt.Sprintf("~r%d", i)
-	n = newname(Lookup(namebuf))
+	n := newname(Lookup(namebuf))
 	n.Type = t.Type
 	n.Class = PAUTO
 	n.Used = 1
@@ -887,10 +841,8 @@
 // Synthesize a variable to store the inlined function's arguments
 // when they come from a multiple return call.
 func argvar(t *Type, i int) *Node {
-	var n *Node
-
 	namebuf = fmt.Sprintf("~arg%d", i)
-	n = newname(Lookup(namebuf))
+	n := newname(Lookup(namebuf))
 	n.Type = t.Type
 	n.Class = PAUTO
 	n.Used = 1
@@ -902,11 +854,9 @@
 var newlabel_inl_label int
 
 func newlabel_inl() *Node {
-	var n *Node
-
 	newlabel_inl_label++
 	namebuf = fmt.Sprintf(".inlret%.6d", newlabel_inl_label)
-	n = newname(Lookup(namebuf))
+	n := newname(Lookup(namebuf))
 	n.Etype = 1 // flag 'safe' for escape analysis (no backjumps)
 	return n
 }
@@ -916,9 +866,7 @@
 // to input/output parameters with ones to the tmpnames, and
 // substituting returns with assignments to the output.
 func inlsubstlist(ll *NodeList) *NodeList {
-	var l *NodeList
-
-	l = nil
+	l := (*NodeList)(nil)
 	for ; ll != nil; ll = ll.Next {
 		l = list(l, inlsubst(ll.N))
 	}
@@ -926,11 +874,6 @@
 }
 
 func inlsubst(n *Node) *Node {
-	var p string
-	var m *Node
-	var as *Node
-	var ll *NodeList
-
 	if n == nil {
 		return nil
 	}
@@ -957,15 +900,15 @@
 
 	//		dump("Return before substitution", n);
 	case ORETURN:
-		m = Nod(OGOTO, inlretlabel, nil)
+		m := Nod(OGOTO, inlretlabel, nil)
 
 		m.Ninit = inlsubstlist(n.Ninit)
 
 		if inlretvars != nil && n.List != nil {
-			as = Nod(OAS2, nil, nil)
+			as := Nod(OAS2, nil, nil)
 
 			// shallow copy or OINLCALL->rlist will be the same list, and later walk and typecheck may clobber that.
-			for ll = inlretvars; ll != nil; ll = ll.Next {
+			for ll := inlretvars; ll != nil; ll = ll.Next {
 				as.List = list(as.List, ll.N)
 			}
 			as.Rlist = inlsubstlist(n.List)
@@ -981,16 +924,16 @@
 
 	case OGOTO,
 		OLABEL:
-		m = Nod(OXXX, nil, nil)
+		m := Nod(OXXX, nil, nil)
 		*m = *n
 		m.Ninit = nil
-		p = fmt.Sprintf("%s·%d", n.Left.Sym.Name, inlgen)
+		p := fmt.Sprintf("%s·%d", n.Left.Sym.Name, inlgen)
 		m.Left = newname(Lookup(p))
 
 		return m
 	}
 
-	m = Nod(OXXX, nil, nil)
+	m := Nod(OXXX, nil, nil)
 	*m = *n
 	m.Ninit = nil
 
diff --git a/src/cmd/internal/gc/lex.go b/src/cmd/internal/gc/lex.go
index 26f2eff..9627337 100644
--- a/src/cmd/internal/gc/lex.go
+++ b/src/cmd/internal/gc/lex.go
@@ -88,14 +88,11 @@
 }
 
 func doversion() {
-	var p string
-	var sep string
-
-	p = obj.Expstring()
+	p := obj.Expstring()
 	if p == "X:none" {
 		p = ""
 	}
-	sep = ""
+	sep := ""
 	if p != "" {
 		sep = " "
 	}
@@ -105,12 +102,10 @@
 
 func Main() {
 	defer hidePanic()
-	var l *NodeList
-	var p string
 
 	// Allow GOARCH=thearch.thestring or GOARCH=thearch.thestringsuffix,
 	// but not other values.
-	p = obj.Getgoarch()
+	p := obj.Getgoarch()
 
 	if !strings.HasPrefix(p, Thearch.Thestring) {
 		log.Fatalf("cannot use %cg with GOARCH=%s", Thearch.Thechar, p)
@@ -276,7 +271,7 @@
 	}
 
 	if Thearch.Thechar == '8' {
-		p = obj.Getgo386()
+		p := obj.Getgo386()
 		if p == "387" {
 			Use_sse = 0
 		} else if p == "sse2" {
@@ -355,7 +350,7 @@
 	//   and methods but doesn't depend on any of it.
 	defercheckwidth()
 
-	for l = xtop; l != nil; l = l.Next {
+	for l := xtop; l != nil; l = l.Next {
 		if l.N.Op != ODCL && l.N.Op != OAS {
 			typecheck(&l.N, Etop)
 		}
@@ -363,7 +358,7 @@
 
 	// Phase 2: Variable assignments.
 	//   To check interface assignments, depends on phase 1.
-	for l = xtop; l != nil; l = l.Next {
+	for l := xtop; l != nil; l = l.Next {
 		if l.N.Op == ODCL || l.N.Op == OAS {
 			typecheck(&l.N, Etop)
 		}
@@ -371,7 +366,7 @@
 	resumecheckwidth()
 
 	// Phase 3: Type check function bodies.
-	for l = xtop; l != nil; l = l.Next {
+	for l := xtop; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC || l.N.Op == OCLOSURE {
 			Curfn = l.N
 			decldepth = 1
@@ -387,7 +382,7 @@
 	// Phase 4: Decide how to capture closed variables.
 	// This needs to run before escape analysis,
 	// because variables captured by value do not escape.
-	for l = xtop; l != nil; l = l.Next {
+	for l := xtop; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC && l.N.Closure != nil {
 			Curfn = l.N
 			capturevars(l.N)
@@ -404,7 +399,7 @@
 	if Debug['l'] > 1 {
 		// Typecheck imported function bodies if debug['l'] > 1,
 		// otherwise lazily when used or re-exported.
-		for l = importlist; l != nil; l = l.Next {
+		for l := importlist; l != nil; l = l.Next {
 			if l.N.Inl != nil {
 				saveerrors()
 				typecheckinl(l.N)
@@ -418,14 +413,14 @@
 
 	if Debug['l'] != 0 {
 		// Find functions that can be inlined and clone them before walk expands them.
-		for l = xtop; l != nil; l = l.Next {
+		for l := xtop; l != nil; l = l.Next {
 			if l.N.Op == ODCLFUNC {
 				caninl(l.N)
 			}
 		}
 
 		// Expand inlineable calls in all functions
-		for l = xtop; l != nil; l = l.Next {
+		for l := xtop; l != nil; l = l.Next {
 			if l.N.Op == ODCLFUNC {
 				inlcalls(l.N)
 			}
@@ -447,7 +442,7 @@
 	// Phase 7: Transform closure bodies to properly reference captured variables.
 	// This needs to happen before walk, because closures must be transformed
 	// before walk reaches a call of a closure.
-	for l = xtop; l != nil; l = l.Next {
+	for l := xtop; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC && l.N.Closure != nil {
 			Curfn = l.N
 			transformclosure(l.N)
@@ -457,7 +452,7 @@
 	Curfn = nil
 
 	// Phase 8: Compile top level functions.
-	for l = xtop; l != nil; l = l.Next {
+	for l := xtop; l != nil; l = l.Next {
 		if l.N.Op == ODCLFUNC {
 			funccompile(l.N)
 		}
@@ -468,7 +463,7 @@
 	}
 
 	// Phase 9: Check external declarations.
-	for l = externdcl; l != nil; l = l.Next {
+	for l := externdcl; l != nil; l = l.Next {
 		if l.N.Op == ONAME {
 			typecheck(&l.N, Erv)
 		}
@@ -511,11 +506,8 @@
 }
 
 func skiptopkgdef(b *obj.Biobuf) bool {
-	var p string
-	var sz int
-
 	/* archive header */
-	p = obj.Brdline(b, '\n')
+	p := obj.Brdline(b, '\n')
 	if p == "" {
 		return false
 	}
@@ -527,7 +519,7 @@
 	}
 
 	/* symbol table may be first; skip it */
-	sz = arsize(b, "__.GOSYMDEF")
+	sz := arsize(b, "__.GOSYMDEF")
 
 	if sz >= 0 {
 		obj.Bseek(b, int64(sz), 1)
@@ -545,12 +537,11 @@
 }
 
 func addidir(dir string) {
-	var pp **Idir
-
 	if dir == "" {
 		return
 	}
 
+	var pp **Idir
 	for pp = &idirs; *pp != nil; pp = &(*pp).link {
 	}
 	*pp = new(Idir)
@@ -567,11 +558,6 @@
 }
 
 func findpkg(name *Strlit) bool {
-	var p *Idir
-	var q string
-	var suffix string
-	var suffixsep string
-
 	if islocalname(name) {
 		if safemode != 0 || nolocalimports != 0 {
 			return false
@@ -595,13 +581,14 @@
 	// local imports should be canonicalized already.
 	// don't want to see "encoding/../encoding/base64"
 	// as different from "encoding/base64".
+	var q string
 	_ = q
 	if path.Clean(name.S) != name.S {
 		Yyerror("non-canonical import path %v (should be %s)", Zconv(name, 0), q)
 		return false
 	}
 
-	for p = idirs; p != nil; p = p.link {
+	for p := idirs; p != nil; p = p.link {
 		namebuf = fmt.Sprintf("%s/%v.a", p.dir, Zconv(name, 0))
 		if obj.Access(namebuf, 0) >= 0 {
 			return true
@@ -613,8 +600,8 @@
 	}
 
 	if goroot != "" {
-		suffix = ""
-		suffixsep = ""
+		suffix := ""
+		suffixsep := ""
 		if flag_installsuffix != "" {
 			suffixsep = "_"
 			suffix = flag_installsuffix
@@ -642,17 +629,6 @@
 }
 
 func importfile(f *Val, line int) {
-	var imp *obj.Biobuf
-	var file string
-	var p string
-	var q string
-	var tag string
-	var c int32
-	var n int
-	var path_ *Strlit
-	var cleanbuf string
-	var prefix string
-
 	if f.Ctype != CTSTR {
 		Yyerror("import statement not a string")
 		fakeimport()
@@ -696,7 +672,7 @@
 		return
 	}
 
-	path_ = f.U.Sval
+	path_ := f.U.Sval
 	if islocalname(path_) {
 		if path_.S[0] == '/' {
 			Yyerror("import path cannot be absolute path")
@@ -704,11 +680,11 @@
 			return
 		}
 
-		prefix = Ctxt.Pathname
+		prefix := Ctxt.Pathname
 		if localimport != "" {
 			prefix = localimport
 		}
-		cleanbuf = prefix
+		cleanbuf := prefix
 		cleanbuf += "/"
 		cleanbuf += path_.S
 		cleanbuf = path.Clean(cleanbuf)
@@ -730,13 +706,13 @@
 	// If we already saw that package, feed a dummy statement
 	// to the lexer to avoid parsing export data twice.
 	if importpkg.Imported != 0 {
-		file = namebuf
-		tag = ""
+		file := namebuf
+		tag := ""
 		if importpkg.Safe {
 			tag = "safe"
 		}
 
-		p = fmt.Sprintf("package %s %s\n$$\n", importpkg.Name, tag)
+		p := fmt.Sprintf("package %s %s\n$$\n", importpkg.Name, tag)
 		cannedimports(file, p)
 		return
 	}
@@ -744,15 +720,16 @@
 	importpkg.Imported = 1
 
 	var err error
+	var imp *obj.Biobuf
 	imp, err = obj.Bopenr(namebuf)
 	if err != nil {
 		Yyerror("can't open import: \"%v\": %v", Zconv(f.U.Sval, 0), err)
 		errorexit()
 	}
 
-	file = namebuf
+	file := namebuf
 
-	n = len(namebuf)
+	n := len(namebuf)
 	if n > 2 && namebuf[n-2] == '.' && namebuf[n-1] == 'a' {
 		if !skiptopkgdef(imp) {
 			Yyerror("import %s: not a package file", file)
@@ -761,7 +738,7 @@
 	}
 
 	// check object header
-	p = obj.Brdstr(imp, '\n', 1)
+	p := obj.Brdstr(imp, '\n', 1)
 
 	if p != "empty archive" {
 		if !strings.HasPrefix(p, "go object ") {
@@ -769,7 +746,7 @@
 			errorexit()
 		}
 
-		q = fmt.Sprintf("%s %s %s %s", obj.Getgoos(), obj.Getgoarch(), obj.Getgoversion(), obj.Expstring())
+		q := fmt.Sprintf("%s %s %s %s", obj.Getgoos(), obj.Getgoarch(), obj.Getgoversion(), obj.Expstring())
 		if p[10:] != q {
 			Yyerror("import %s: object is [%s] expected [%s]", file, p[10:], q)
 			errorexit()
@@ -793,6 +770,7 @@
 	curio.nlsemi = 0
 	typecheckok = 1
 
+	var c int32
 	for {
 		c = int32(getc())
 		if c == EOF {
@@ -951,7 +929,6 @@
 		cp.Reset()
 
 		for {
-
 			if escchar('"', &escflag, &v) {
 				break
 			}
@@ -974,7 +951,6 @@
 		cp.Reset()
 
 		for {
-
 			c = int(getr())
 			if c == '\r' {
 				continue
@@ -1014,9 +990,7 @@
 	case '/':
 		c1 = getc()
 		if c1 == '*' {
-			var nl int
-
-			nl = 0
+			nl := 0
 			for {
 				c = int(getr())
 				if c == '\n' {
@@ -1297,7 +1271,6 @@
 	 */
 talph:
 	for {
-
 		if c >= utf8.RuneSelf {
 			ungetc(c)
 			rune_ = uint(getr())
@@ -1339,7 +1312,6 @@
 	cp.Reset()
 	if c != '0' {
 		for {
-
 			cp.WriteByte(byte(c))
 			c = getc()
 			if yy_isdigit(c) {
@@ -1353,7 +1325,6 @@
 	c = getc()
 	if c == 'x' || c == 'X' {
 		for {
-
 			cp.WriteByte(byte(c))
 			c = getc()
 			if yy_isdigit(c) {
@@ -1381,7 +1352,6 @@
 
 	c1 = 0
 	for {
-
 		if !yy_isdigit(c) {
 			break
 		}
@@ -1436,7 +1406,6 @@
 
 casedot:
 	for {
-
 		cp.WriteByte(byte(c))
 		c = getc()
 		if !yy_isdigit(c) {
@@ -1463,7 +1432,6 @@
 		Yyerror("malformed fp constant exponent")
 	}
 	for yy_isdigit(c) {
-
 		cp.WriteByte(byte(c))
 		c = getc()
 	}
@@ -1533,21 +1501,18 @@
  */
 func getlinepragma() int {
 	var cmd, verb, name string
-	var i int
-	var c int
 	var n int
 	var cp *bytes.Buffer
 	var linep int
-	var h *obj.Hist
 
-	c = int(getr())
+	c := int(getr())
 	if c == 'g' {
 		goto go_
 	}
 	if c != 'l' {
 		goto out
 	}
-	for i = 1; i < 5; i++ {
+	for i := 1; i < 5; i++ {
 		c = int(getr())
 		if c != int("line "[i]) {
 			goto out
@@ -1597,7 +1562,7 @@
 
 	// try to avoid allocating file name over and over
 	name = lexbuf.String()[:linep-1]
-	for h = Ctxt.Hist; h != nil; h = h.Link {
+	for h := Ctxt.Hist; h != nil; h = h.Link {
 		if h.Name != "" && h.Name == name {
 			linehist(h.Name, int32(n), 0)
 			goto out
@@ -1708,20 +1673,17 @@
 // Copied nearly verbatim from the C compiler's #pragma parser.
 // TODO: Rewrite more cleanly once the compiler is written in Go.
 func pragcgo(text string) {
-	var local string
-	var remote string
-	var p string
 	var q string
-	var verb string
 
 	if i := strings.Index(text, " "); i >= 0 {
 		text, q = text[:i], text[i:]
 	}
 
-	verb = text[3:] // skip "go:"
+	verb := text[3:] // skip "go:"
 
 	if verb == "cgo_dynamic_linker" || verb == "dynlinker" {
 		var ok bool
+		var p string
 		p, ok = getquoted(&q)
 		if !ok {
 			goto err1
@@ -1738,7 +1700,8 @@
 		verb = "cgo_export_dynamic"
 	}
 	if verb == "cgo_export_static" || verb == "cgo_export_dynamic" {
-		local = getimpsym(&q)
+		local := getimpsym(&q)
+		var remote string
 		if local == "" {
 			goto err2
 		}
@@ -1761,7 +1724,9 @@
 
 	if verb == "cgo_import_dynamic" || verb == "dynimport" {
 		var ok bool
-		local = getimpsym(&q)
+		local := getimpsym(&q)
+		var p string
+		var remote string
 		if local == "" {
 			goto err3
 		}
@@ -1792,7 +1757,7 @@
 	}
 
 	if verb == "cgo_import_static" {
-		local = getimpsym(&q)
+		local := getimpsym(&q)
 		if local == "" || more(&q) {
 			goto err4
 		}
@@ -1806,6 +1771,7 @@
 
 	if verb == "cgo_ldflag" {
 		var ok bool
+		var p string
 		p, ok = getquoted(&q)
 		if !ok {
 			goto err5
@@ -1847,9 +1813,7 @@
 }
 
 func yylex(yylval *yySymType) int32 {
-	var lx int
-
-	lx = int(_yylex(yylval))
+	lx := int(_yylex(yylval))
 
 	if curio.nlsemi != 0 && lx == EOF {
 		// Treat EOF as "end of line" for the purposes
@@ -1883,11 +1847,7 @@
 }
 
 func getc() int {
-	var c int
-	var c1 int
-	var c2 int
-
-	c = curio.peekc
+	c := curio.peekc
 	if c != 0 {
 		curio.peekc = curio.peekc1
 		curio.peekc1 = 0
@@ -1902,6 +1862,8 @@
 			curio.cp = curio.cp[1:]
 		}
 	} else {
+		var c1 int
+		var c2 int
 	loop:
 		c = obj.Bgetc(curio.bin)
 		if c == 0xef {
@@ -1974,14 +1936,9 @@
 }
 
 func escchar(e int, escflg *int, val *int64) bool {
-	var i int
-	var u int
-	var c int
-	var l int64
-
 	*escflg = 0
 
-	c = int(getr())
+	c := int(getr())
 	switch c {
 	case EOF:
 		Yyerror("eof in string")
@@ -2002,8 +1959,10 @@
 		return false
 	}
 
-	u = 0
+	u := 0
 	c = int(getr())
+	var l int64
+	var i int
 	switch c {
 	case 'x':
 		*escflg = 1 // it's a byte
@@ -2091,7 +2050,7 @@
 
 oct:
 	l = int64(c) - '0'
-	for i = 2; i > 0; i-- {
+	for i := 2; i > 0; i-- {
 		c = getc()
 		if c >= '0' && c <= '7' {
 			l = l*8 + int64(c) - '0'
@@ -2482,19 +2441,17 @@
 }
 
 func lexinit() {
-	var i int
 	var lex int
 	var s *Sym
 	var s1 *Sym
 	var t *Type
 	var etype int
-	var v Val
 
 	/*
 	 * initialize basic types array
 	 * initialize known symbols
 	 */
-	for i = 0; i < len(syms); i++ {
+	for i := 0; i < len(syms); i++ {
 		lex = syms[i].lexical
 		s = Lookup(syms[i].name)
 		s.Lexical = uint16(lex)
@@ -2568,33 +2525,26 @@
 
 	Types[TNIL] = typ(TNIL)
 	s = Pkglookup("nil", builtinpkg)
+	var v Val
 	v.Ctype = CTNIL
 	s.Def = nodlit(v)
 	s.Def.Sym = s
 }
 
 func lexinit1() {
-	var s *Sym
-	var s1 *Sym
-	var t *Type
-	var f *Type
-	var rcvr *Type
-	var in *Type
-	var out *Type
-
 	// t = interface { Error() string }
-	rcvr = typ(TSTRUCT)
+	rcvr := typ(TSTRUCT)
 
 	rcvr.Type = typ(TFIELD)
 	rcvr.Type.Type = Ptrto(typ(TSTRUCT))
 	rcvr.Funarg = 1
-	in = typ(TSTRUCT)
+	in := typ(TSTRUCT)
 	in.Funarg = 1
-	out = typ(TSTRUCT)
+	out := typ(TSTRUCT)
 	out.Type = typ(TFIELD)
 	out.Type.Type = Types[TSTRING]
 	out.Funarg = 1
-	f = typ(TFUNC)
+	f := typ(TFUNC)
 	*getthis(f) = rcvr
 	*Getoutarg(f) = out
 	*getinarg(f) = in
@@ -2602,16 +2552,16 @@
 	f.Intuple = 0
 	f.Outnamed = 0
 	f.Outtuple = 1
-	t = typ(TINTER)
+	t := typ(TINTER)
 	t.Type = typ(TFIELD)
 	t.Type.Sym = Lookup("Error")
 	t.Type.Type = f
 
 	// error type
-	s = Lookup("error")
+	s := Lookup("error")
 
 	s.Lexical = LNAME
-	s1 = Pkglookup("error", builtinpkg)
+	s1 := Pkglookup("error", builtinpkg)
 	errortype = t
 	errortype.Sym = s1
 	s1.Lexical = LNAME
@@ -2643,7 +2593,6 @@
 	var lex int
 	var etype int
 	var i int
-	var v Val
 
 	for i = 0; i < len(syms); i++ {
 		lex = syms[i].lexical
@@ -2701,6 +2650,7 @@
 
 	s = Lookup("nil")
 	if s.Def == nil {
+		var v Val
 		v.Ctype = CTNIL
 		s.Def = nodlit(v)
 		s.Def.Sym = s
@@ -2920,9 +2870,7 @@
 var lexname_buf string
 
 func lexname(lex int) string {
-	var i int
-
-	for i = 0; i < len(lexn); i++ {
+	for i := 0; i < len(lexn); i++ {
 		if lexn[i].lex == lex {
 			return lexn[i].name
 		}
@@ -3131,15 +3079,13 @@
 }
 
 func pkgnotused(lineno int, path_ *Strlit, name string) {
-	var elem string
-
 	// If the package was imported with a name other than the final
 	// import path element, show it explicitly in the error message.
 	// Note that this handles both renamed imports and imports of
 	// packages containing unconventional package declarations.
 	// Note that this uses / always, even on Windows, because Go import
 	// paths always use forward slashes.
-	elem = path_.S
+	elem := path_.S
 	if i := strings.LastIndex(elem, "/"); i >= 0 {
 		elem = elem[i+1:]
 	}
@@ -3151,10 +3097,6 @@
 }
 
 func mkpackage(pkgname string) {
-	var s *Sym
-	var h int32
-	var p string
-
 	if localpkg.Name == "" {
 		if pkgname == "_" {
 			Yyerror("invalid package name _")
@@ -3164,7 +3106,8 @@
 		if pkgname != localpkg.Name {
 			Yyerror("package %s; expected %s", pkgname, localpkg.Name)
 		}
-		for h = 0; h < NHASH; h++ {
+		var s *Sym
+		for h := int32(0); h < NHASH; h++ {
 			for s = hash[h]; s != nil; s = s.Link {
 				if s.Def == nil || s.Pkg != localpkg {
 					continue
@@ -3198,7 +3141,7 @@
 	}
 
 	if outfile == "" {
-		p = infile
+		p := infile
 		if i := strings.LastIndex(p, "/"); i >= 0 {
 			p = p[i+1:]
 		}
diff --git a/src/cmd/internal/gc/md5.go b/src/cmd/internal/gc/md5.go
index 862fdd5..3b51900 100644
--- a/src/cmd/internal/gc/md5.go
+++ b/src/cmd/internal/gc/md5.go
@@ -39,16 +39,13 @@
 }
 
 func md5write(d *MD5, p []byte, nn int) {
-	var i int
-	var n int
-
 	d.len += uint64(nn)
 	if d.nx > 0 {
-		n = nn
+		n := nn
 		if n > _Chunk-d.nx {
 			n = _Chunk - d.nx
 		}
-		for i = 0; i < n; i++ {
+		for i := 0; i < n; i++ {
 			d.x[d.nx+i] = uint8(p[i])
 		}
 		d.nx += n
@@ -61,11 +58,11 @@
 		nn -= n
 	}
 
-	n = md5block(d, p, nn)
+	n := md5block(d, p, nn)
 	p = p[n:]
 	nn -= n
 	if nn > 0 {
-		for i = 0; i < nn; i++ {
+		for i := 0; i < nn; i++ {
 			d.x[i] = uint8(p[i])
 		}
 		d.nx = nn
@@ -73,14 +70,10 @@
 }
 
 func md5sum(d *MD5, hi *uint64) uint64 {
-	var tmp [64]uint8
-	var i int
-	var len uint64
-
 	// Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
-	len = d.len
+	len := d.len
 
-	tmp = [64]uint8{}
+	tmp := [64]uint8{}
 	tmp[0] = 0x80
 	if len%64 < 56 {
 		md5write(d, tmp[:], int(56-len%64))
@@ -91,7 +84,7 @@
 	// Length in bits.
 	len <<= 3
 
-	for i = 0; i < 8; i++ {
+	for i := 0; i < 8; i++ {
 		tmp[i] = uint8(len >> uint(8*i))
 	}
 	md5write(d, tmp[:], 8)
@@ -194,24 +187,19 @@
 var shift4 = []uint32{6, 10, 15, 21}
 
 func md5block(dig *MD5, p []byte, nn int) int {
-	var a uint32
-	var b uint32
-	var c uint32
-	var d uint32
 	var aa uint32
 	var bb uint32
 	var cc uint32
 	var dd uint32
 	var i int
 	var j int
-	var n int
 	var X [16]uint32
 
-	a = dig.s[0]
-	b = dig.s[1]
-	c = dig.s[2]
-	d = dig.s[3]
-	n = 0
+	a := dig.s[0]
+	b := dig.s[1]
+	c := dig.s[2]
+	d := dig.s[3]
+	n := 0
 
 	for nn >= _Chunk {
 		aa = a
@@ -226,14 +214,10 @@
 
 		// Round 1.
 		for i = 0; i < 16; i++ {
-			var x uint32
-			var t uint32
-			var s uint32
-			var f uint32
-			x = uint32(i)
-			t = uint32(i)
-			s = shift1[i%4]
-			f = ((c ^ d) & b) ^ d
+			x := uint32(i)
+			t := uint32(i)
+			s := shift1[i%4]
+			f := ((c ^ d) & b) ^ d
 			a += f + X[x] + table[t]
 			a = a<<s | a>>(32-s)
 			a += b
@@ -247,15 +231,10 @@
 
 		// Round 2.
 		for i = 0; i < 16; i++ {
-			var x uint32
-			var t uint32
-			var s uint32
-			var g uint32
-
-			x = (1 + 5*uint32(i)) % 16
-			t = 16 + uint32(i)
-			s = shift2[i%4]
-			g = ((b ^ c) & d) ^ c
+			x := (1 + 5*uint32(i)) % 16
+			t := 16 + uint32(i)
+			s := shift2[i%4]
+			g := ((b ^ c) & d) ^ c
 			a += g + X[x] + table[t]
 			a = a<<s | a>>(32-s)
 			a += b
@@ -269,15 +248,10 @@
 
 		// Round 3.
 		for i = 0; i < 16; i++ {
-			var x uint32
-			var t uint32
-			var s uint32
-			var h uint32
-
-			x = (5 + 3*uint32(i)) % 16
-			t = 32 + uint32(i)
-			s = shift3[i%4]
-			h = b ^ c ^ d
+			x := (5 + 3*uint32(i)) % 16
+			t := 32 + uint32(i)
+			s := shift3[i%4]
+			h := b ^ c ^ d
 			a += h + X[x] + table[t]
 			a = a<<s | a>>(32-s)
 			a += b
@@ -291,15 +265,10 @@
 
 		// Round 4.
 		for i = 0; i < 16; i++ {
-			var x uint32
-			var s uint32
-			var t uint32
-			var ii uint32
-
-			x = (7 * uint32(i)) % 16
-			s = shift4[i%4]
-			t = 48 + uint32(i)
-			ii = c ^ (b | ^d)
+			x := (7 * uint32(i)) % 16
+			s := shift4[i%4]
+			t := 48 + uint32(i)
+			ii := c ^ (b | ^d)
 			a += ii + X[x] + table[t]
 			a = a<<s | a>>(32-s)
 			a += b
diff --git a/src/cmd/internal/gc/mparith1.go b/src/cmd/internal/gc/mparith1.go
index 14b8620..454b688 100644
--- a/src/cmd/internal/gc/mparith1.go
+++ b/src/cmd/internal/gc/mparith1.go
@@ -13,19 +13,17 @@
 /// uses arithmetic
 
 func mpcmpfixflt(a *Mpint, b *Mpflt) int {
-	var buf string
 	var c Mpflt
 
-	buf = fmt.Sprintf("%v", Bconv(a, 0))
+	buf := fmt.Sprintf("%v", Bconv(a, 0))
 	mpatoflt(&c, buf)
 	return mpcmpfltflt(&c, b)
 }
 
 func mpcmpfltfix(a *Mpflt, b *Mpint) int {
-	var buf string
 	var c Mpflt
 
-	buf = fmt.Sprintf("%v", Bconv(b, 0))
+	buf := fmt.Sprintf("%v", Bconv(b, 0))
 	mpatoflt(&c, buf)
 	return mpcmpfltflt(a, &c)
 }
@@ -133,11 +131,10 @@
 // convert (truncate) b to a.
 // return -1 (but still convert) if b was non-integer.
 func mpexactfltfix(a *Mpint, b *Mpflt) int {
-	var f Mpflt
-
 	*a = b.Val
 	Mpshiftfix(a, int(b.Exp))
 	if b.Exp < 0 {
+		var f Mpflt
 		f.Val = *a
 		f.Exp = 0
 		mpnorm(&f)
@@ -150,15 +147,12 @@
 }
 
 func mpmovefltfix(a *Mpint, b *Mpflt) int {
-	var f Mpflt
-	var i int
-
 	if mpexactfltfix(a, b) == 0 {
 		return 0
 	}
 
 	// try rounding down a little
-	f = *b
+	f := *b
 
 	f.Val.A[0] = 0
 	if mpexactfltfix(a, &f) == 0 {
@@ -166,7 +160,7 @@
 	}
 
 	// try rounding up a little
-	for i = 1; i < Mpprec; i++ {
+	for i := 1; i < Mpprec; i++ {
 		f.Val.A[i]++
 		if f.Val.A[i] != Mpbase {
 			break
@@ -209,12 +203,6 @@
 }
 
 func mphextofix(a *Mpint, s string) {
-	var c int8
-	var d int
-	var bit int
-	var hexdigitp int
-	var end int
-
 	for s != "" && s[0] == '0' {
 		s = s[1:]
 	}
@@ -225,8 +213,11 @@
 		return
 	}
 
-	end = len(s) - 1
-	for hexdigitp = end; hexdigitp >= 0; hexdigitp-- {
+	end := len(s) - 1
+	var c int8
+	var d int
+	var bit int
+	for hexdigitp := end; hexdigitp >= 0; hexdigitp-- {
 		c = int8(s[hexdigitp])
 		if c >= '0' && c <= '9' {
 			d = int(c) - '0'
@@ -252,25 +243,14 @@
 // required syntax is [+-]d*[.]d*[e[+-]d*] or [+-]0xH*[e[+-]d*]
 //
 func mpatoflt(a *Mpflt, as string) {
-	var b Mpflt
-	var dp int
-	var c int
-	var f int
-	var ef int
-	var ex int
-	var eb int
-	var base int
-	var s string
-	var start string
-
 	for as[0] == ' ' || as[0] == '\t' {
 		as = as[1:]
 	}
 
 	/* determine base */
-	s = as
+	s := as
 
-	base = -1
+	base := -1
 	for base == -1 {
 		if s == "" {
 			base = 10
@@ -296,14 +276,17 @@
 	}
 
 	s = as
-	dp = 0 /* digits after decimal point */
-	f = 0  /* sign */
-	ex = 0 /* exponent */
-	eb = 0 /* binary point */
+	dp := 0 /* digits after decimal point */
+	f := 0  /* sign */
+	ex := 0 /* exponent */
+	eb := 0 /* binary point */
 
 	Mpmovecflt(a, 0.0)
+	var ef int
+	var c int
 	if base == 16 {
-		start = ""
+		start := ""
+		var c int
 		for {
 			c, _ = intstarstringplusplus(s)
 			if c == '-' {
@@ -437,6 +420,7 @@
 	}
 	if mpcmpfltc(a, 0.0) != 0 {
 		if ex >= dp {
+			var b Mpflt
 			mppow10flt(&b, ex-dp)
 			mpmulfltflt(a, &b)
 		} else {
@@ -444,6 +428,7 @@
 			if dp-ex >= 1<<(32-3) || int(int16(4*(dp-ex))) != 4*(dp-ex) {
 				Mpmovecflt(a, 0.0)
 			} else {
+				var b Mpflt
 				mppow10flt(&b, dp-ex)
 				mpdivfltflt(a, &b)
 			}
@@ -466,12 +451,10 @@
 //
 func mpatofix(a *Mpint, as string) {
 	var c int
-	var f int
-	var s string
 	var s0 string
 
-	s = as
-	f = 0
+	s := as
+	f := 0
 	Mpmovecfix(a, 0)
 
 	c, s = intstarstringplusplus(s)
@@ -555,29 +538,24 @@
 }
 
 func Bconv(xval *Mpint, flag int) string {
-	var buf [500]byte
-	var p int
-	var fp string
-
 	var q Mpint
-	var r Mpint
-	var ten Mpint
-	var sixteen Mpint
-	var f int
-	var digit int
 
 	mpmovefixfix(&q, xval)
-	f = 0
+	f := 0
 	if mptestfix(&q) < 0 {
 		f = 1
 		mpnegfix(&q)
 	}
 
-	p = len(buf)
+	var buf [500]byte
+	p := len(buf)
+	var r Mpint
 	if flag&obj.FmtSharp != 0 /*untyped*/ {
 		// Hexadecimal
+		var sixteen Mpint
 		Mpmovecfix(&sixteen, 16)
 
+		var digit int
 		for {
 			mpdivmodfixfix(&q, &r, &q, &sixteen)
 			digit = int(Mpgetfix(&r))
@@ -599,6 +577,7 @@
 		buf[p] = '0'
 	} else {
 		// Decimal
+		var ten Mpint
 		Mpmovecfix(&ten, 10)
 
 		for {
@@ -615,26 +594,20 @@
 		p--
 		buf[p] = '-'
 	}
+	var fp string
 	fp += string(buf[p:])
 	return fp
 }
 
 func Fconv(fvp *Mpflt, flag int) string {
-	var buf string
-	var fp string
-
-	var fv Mpflt
-	var d float64
-	var dexp float64
-	var exp int
-
 	if flag&obj.FmtSharp != 0 /*untyped*/ {
 		// alternate form - decimal for error messages.
 		// for well in range, convert to double and use print's %g
-		exp = int(fvp.Exp) + sigfig(fvp)*Mpscale
+		exp := int(fvp.Exp) + sigfig(fvp)*Mpscale
 
+		var fp string
 		if -900 < exp && exp < 900 {
-			d = mpgetflt(fvp)
+			d := mpgetflt(fvp)
 			if d >= 0 && (flag&obj.FmtSign != 0 /*untyped*/) {
 				fp += fmt.Sprintf("+")
 			}
@@ -644,15 +617,15 @@
 
 		// very out of range. compute decimal approximation by hand.
 		// decimal exponent
-		dexp = float64(fvp.Exp) * 0.301029995663981195 // log_10(2)
+		dexp := float64(fvp.Exp) * 0.301029995663981195 // log_10(2)
 		exp = int(dexp)
 
 		// decimal mantissa
-		fv = *fvp
+		fv := *fvp
 
 		fv.Val.Neg = 0
 		fv.Exp = 0
-		d = mpgetflt(&fv)
+		d := mpgetflt(&fv)
 		d *= math.Pow(10, dexp-float64(exp))
 		for d >= 9.99995 {
 			d /= 10
@@ -668,6 +641,8 @@
 		return fp
 	}
 
+	var fv Mpflt
+	var buf string
 	if sigfig(fvp) == 0 {
 		buf = fmt.Sprintf("0p+0")
 		goto out
@@ -693,6 +668,7 @@
 	buf = fmt.Sprintf("%vp-%d", Bconv(&fv.Val, obj.FmtSharp), -fv.Exp)
 
 out:
+	var fp string
 	fp += buf
 	return fp
 }
diff --git a/src/cmd/internal/gc/mparith2.go b/src/cmd/internal/gc/mparith2.go
index 057585c..c9c9230 100644
--- a/src/cmd/internal/gc/mparith2.go
+++ b/src/cmd/internal/gc/mparith2.go
@@ -9,11 +9,8 @@
 // words of the argument
 //
 func mplen(a *Mpint) int {
-	var i int
-	var n int
-
-	n = -1
-	for i = 0; i < Mpprec; i++ {
+	n := -1
+	for i := 0; i < Mpprec; i++ {
 		if a.A[i] != 0 {
 			n = i
 		}
@@ -28,11 +25,9 @@
 //
 func mplsh(a *Mpint, quiet int) {
 	var x int
-	var i int
-	var c int
 
-	c = 0
-	for i = 0; i < Mpprec; i++ {
+	c := 0
+	for i := 0; i < Mpprec; i++ {
 		x = (a.A[i] << 1) + c
 		c = 0
 		if x >= Mpbase {
@@ -54,9 +49,7 @@
 // ignores sign
 //
 func mplshw(a *Mpint, quiet int) {
-	var i int
-
-	i = Mpprec - 1
+	i := Mpprec - 1
 	if a.A[i] != 0 {
 		a.Ovf = 1
 		if quiet == 0 {
@@ -76,13 +69,10 @@
 //
 func mprsh(a *Mpint) {
 	var x int
-	var lo int
-	var i int
-	var c int
 
-	c = 0
-	lo = a.A[0] & 1
-	for i = Mpprec - 1; i >= 0; i-- {
+	c := 0
+	lo := a.A[0] & 1
+	for i := Mpprec - 1; i >= 0; i-- {
 		x = a.A[i]
 		a.A[i] = (x + c) >> 1
 		c = 0
@@ -101,10 +91,9 @@
 // ignores sign and overflow
 //
 func mprshw(a *Mpint) {
-	var lo int
 	var i int
 
-	lo = a.A[0]
+	lo := a.A[0]
 	for i = 0; i < Mpprec-1; i++ {
 		a.A[i] = a.A[i+1]
 	}
@@ -119,9 +108,6 @@
 // return the sign of (abs(a)-abs(b))
 //
 func mpcmp(a *Mpint, b *Mpint) int {
-	var x int
-	var i int
-
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in cmp")
@@ -129,7 +115,8 @@
 		return 0
 	}
 
-	for i = Mpprec - 1; i >= 0; i-- {
+	var x int
+	for i := Mpprec - 1; i >= 0; i-- {
 		x = a.A[i] - b.A[i]
 		if x > 0 {
 			return +1
@@ -148,11 +135,9 @@
 //
 func mpneg(a *Mpint) {
 	var x int
-	var i int
-	var c int
 
-	c = 0
-	for i = 0; i < Mpprec; i++ {
+	c := 0
+	for i := 0; i < Mpprec; i++ {
 		x = -a.A[i] - c
 		c = 0
 		if x < 0 {
@@ -193,10 +178,6 @@
 /// implements fix arihmetic
 
 func mpaddfixfix(a *Mpint, b *Mpint, quiet int) {
-	var i int
-	var c int
-	var x int
-
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mpaddxx")
@@ -205,13 +186,14 @@
 		return
 	}
 
-	c = 0
+	c := 0
+	var x int
 	if a.Neg != b.Neg {
 		goto sub
 	}
 
 	// perform a+b
-	for i = 0; i < Mpprec; i++ {
+	for i := 0; i < Mpprec; i++ {
 		x = a.A[i] + b.A[i] + c
 		c = 0
 		if x >= Mpbase {
@@ -236,7 +218,8 @@
 		Mpmovecfix(a, 0)
 
 	case 1:
-		for i = 0; i < Mpprec; i++ {
+		var x int
+		for i := 0; i < Mpprec; i++ {
 			x = a.A[i] - b.A[i] - c
 			c = 0
 			if x < 0 {
@@ -249,7 +232,8 @@
 
 	case -1:
 		a.Neg ^= 1
-		for i = 0; i < Mpprec; i++ {
+		var x int
+		for i := 0; i < Mpprec; i++ {
 			x = b.A[i] - a.A[i] - c
 			c = 0
 			if x < 0 {
@@ -263,15 +247,6 @@
 }
 
 func mpmulfixfix(a *Mpint, b *Mpint) {
-	var i int
-	var j int
-	var na int
-	var nb int
-	var x int
-	var s Mpint
-	var q Mpint
-	var c *Mpint
-
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mpmulfixfix")
@@ -282,9 +257,11 @@
 
 	// pick the smaller
 	// to test for bits
-	na = mplen(a)
+	na := mplen(a)
 
-	nb = mplen(b)
+	nb := mplen(b)
+	var s Mpint
+	var c *Mpint
 	if na > nb {
 		mpmovefixfix(&s, a)
 		c = b
@@ -296,8 +273,11 @@
 
 	s.Neg = 0
 
+	var q Mpint
 	Mpmovecfix(&q, 0)
-	for i = 0; i < na; i++ {
+	var j int
+	var x int
+	for i := 0; i < na; i++ {
 		x = c.A[i]
 		for j = 0; j < Mpscale; j++ {
 			if x&1 != 0 {
@@ -326,12 +306,6 @@
 }
 
 func mpmulfract(a *Mpint, b *Mpint) {
-	var i int
-	var j int
-	var x int
-	var s Mpint
-	var q Mpint
-
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mpmulflt")
@@ -340,16 +314,19 @@
 		return
 	}
 
+	var s Mpint
 	mpmovefixfix(&s, b)
 	s.Neg = 0
+	var q Mpint
 	Mpmovecfix(&q, 0)
 
-	i = Mpprec - 1
-	x = a.A[i]
+	i := Mpprec - 1
+	x := a.A[i]
 	if x != 0 {
 		Yyerror("mpmulfract not normal")
 	}
 
+	var j int
 	for i--; i >= 0; i-- {
 		x = a.A[i]
 		if x == 0 {
@@ -374,10 +351,7 @@
 }
 
 func mporfixfix(a *Mpint, b *Mpint) {
-	var i int
-	var x int
-
-	x = 0
+	x := 0
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mporfixfix")
@@ -396,7 +370,7 @@
 		mpneg(b)
 	}
 
-	for i = 0; i < Mpprec; i++ {
+	for i := 0; i < Mpprec; i++ {
 		x = a.A[i] | b.A[i]
 		a.A[i] = x
 	}
@@ -411,10 +385,7 @@
 }
 
 func mpandfixfix(a *Mpint, b *Mpint) {
-	var i int
-	var x int
-
-	x = 0
+	x := 0
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mpandfixfix")
@@ -433,7 +404,7 @@
 		mpneg(b)
 	}
 
-	for i = 0; i < Mpprec; i++ {
+	for i := 0; i < Mpprec; i++ {
 		x = a.A[i] & b.A[i]
 		a.A[i] = x
 	}
@@ -448,10 +419,7 @@
 }
 
 func mpandnotfixfix(a *Mpint, b *Mpint) {
-	var i int
-	var x int
-
-	x = 0
+	x := 0
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mpandnotfixfix")
@@ -470,7 +438,7 @@
 		mpneg(b)
 	}
 
-	for i = 0; i < Mpprec; i++ {
+	for i := 0; i < Mpprec; i++ {
 		x = a.A[i] &^ b.A[i]
 		a.A[i] = x
 	}
@@ -485,10 +453,7 @@
 }
 
 func mpxorfixfix(a *Mpint, b *Mpint) {
-	var i int
-	var x int
-
-	x = 0
+	x := 0
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mporfixfix")
@@ -507,7 +472,7 @@
 		mpneg(b)
 	}
 
-	for i = 0; i < Mpprec; i++ {
+	for i := 0; i < Mpprec; i++ {
 		x = a.A[i] ^ b.A[i]
 		a.A[i] = x
 	}
@@ -522,8 +487,6 @@
 }
 
 func mplshfixfix(a *Mpint, b *Mpint) {
-	var s int64
-
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mporfixfix")
@@ -533,7 +496,7 @@
 		return
 	}
 
-	s = Mpgetfix(b)
+	s := Mpgetfix(b)
 	if s < 0 || s >= Mpprec*Mpscale {
 		Yyerror("stupid shift: %d", s)
 		Mpmovecfix(a, 0)
@@ -544,8 +507,6 @@
 }
 
 func mprshfixfix(a *Mpint, b *Mpint) {
-	var s int64
-
 	if a.Ovf != 0 || b.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("ovf in mprshfixfix")
@@ -555,7 +516,7 @@
 		return
 	}
 
-	s = Mpgetfix(b)
+	s := Mpgetfix(b)
 	if s < 0 || s >= Mpprec*Mpscale {
 		Yyerror("stupid shift: %d", s)
 		if a.Neg != 0 {
@@ -574,8 +535,6 @@
 }
 
 func Mpgetfix(a *Mpint) int64 {
-	var v int64
-
 	if a.Ovf != 0 {
 		if nsavederrors+nerrors == 0 {
 			Yyerror("constant overflow")
@@ -583,7 +542,7 @@
 		return 0
 	}
 
-	v = int64(uint64(a.A[0]))
+	v := int64(uint64(a.A[0]))
 	v |= int64(uint64(a.A[1]) << Mpscale)
 	v |= int64(uint64(a.A[2]) << (Mpscale + Mpscale))
 	if a.Neg != 0 {
@@ -593,19 +552,16 @@
 }
 
 func Mpmovecfix(a *Mpint, c int64) {
-	var i int
-	var x int64
-
 	a.Neg = 0
 	a.Ovf = 0
 
-	x = c
+	x := c
 	if x < 0 {
 		a.Neg = 1
 		x = int64(-uint64(x))
 	}
 
-	for i = 0; i < Mpprec; i++ {
+	for i := 0; i < Mpprec; i++ {
 		a.A[i] = int(x & Mpmask)
 		x >>= Mpscale
 	}
@@ -613,11 +569,9 @@
 
 func mpdivmodfixfix(q *Mpint, r *Mpint, n *Mpint, d *Mpint) {
 	var i int
-	var ns int
-	var ds int
 
-	ns = int(n.Neg)
-	ds = int(d.Neg)
+	ns := int(n.Neg)
+	ds := int(d.Neg)
 	n.Neg = 0
 	d.Neg = 0
 
@@ -664,9 +618,7 @@
 }
 
 func mpiszero(a *Mpint) bool {
-	var i int
-
-	for i = Mpprec - 1; i >= 0; i-- {
+	for i := Mpprec - 1; i >= 0; i-- {
 		if a.A[i] != 0 {
 			return false
 		}
@@ -677,19 +629,17 @@
 func mpdivfract(a *Mpint, b *Mpint) {
 	var n Mpint
 	var d Mpint
-	var i int
 	var j int
-	var neg int
 	var x int
 
 	mpmovefixfix(&n, a) // numerator
 	mpmovefixfix(&d, b) // denominator
 
-	neg = int(n.Neg) ^ int(d.Neg)
+	neg := int(n.Neg) ^ int(d.Neg)
 
 	n.Neg = 0
 	d.Neg = 0
-	for i = Mpprec - 1; i >= 0; i-- {
+	for i := Mpprec - 1; i >= 0; i-- {
 		x = 0
 		for j = 0; j < Mpscale; j++ {
 			x <<= 1
@@ -711,10 +661,9 @@
 
 func mptestfix(a *Mpint) int {
 	var b Mpint
-	var r int
 
 	Mpmovecfix(&b, 0)
-	r = mpcmp(a, &b)
+	r := mpcmp(a, &b)
 	if a.Neg != 0 {
 		if r > 0 {
 			return -1
diff --git a/src/cmd/internal/gc/mparith3.go b/src/cmd/internal/gc/mparith3.go
index 61bf9e9..103c53d 100644
--- a/src/cmd/internal/gc/mparith3.go
+++ b/src/cmd/internal/gc/mparith3.go
@@ -49,11 +49,7 @@
  * word of the number to Mpnorm
  */
 func mpnorm(a *Mpflt) {
-	var s int
-	var os int
-	var x int
-
-	os = sigfig(a)
+	os := sigfig(a)
 	if os == 0 {
 		// zero
 		a.Exp = 0
@@ -63,9 +59,9 @@
 	}
 
 	// this will normalize to the nearest word
-	x = a.Val.A[os-1]
+	x := a.Val.A[os-1]
 
-	s = (Mpnorm - os) * Mpscale
+	s := (Mpnorm - os) * Mpscale
 
 	// further normalize to the nearest bit
 	for {
@@ -91,16 +87,13 @@
 /// implements float arihmetic
 
 func mpaddfltflt(a *Mpflt, b *Mpflt) {
-	var sa int
-	var sb int
-	var s int
-	var c Mpflt
-
 	if Mpdebug != 0 /*TypeKind(100016)*/ {
 		fmt.Printf("\n%v + %v", Fconv(a, 0), Fconv(b, 0))
 	}
 
-	sa = sigfig(a)
+	sa := sigfig(a)
+	var s int
+	var sb int
 	if sa == 0 {
 		mpmovefltflt(a, b)
 		goto out
@@ -114,6 +107,7 @@
 	s = int(a.Exp) - int(b.Exp)
 	if s > 0 {
 		// a is larger, shift b right
+		var c Mpflt
 		mpmovefltflt(&c, b)
 
 		Mpshiftfix(&c.Val, -s)
@@ -140,14 +134,11 @@
 }
 
 func mpmulfltflt(a *Mpflt, b *Mpflt) {
-	var sa int
-	var sb int
-
 	if Mpdebug != 0 /*TypeKind(100016)*/ {
 		fmt.Printf("%v\n * %v\n", Fconv(a, 0), Fconv(b, 0))
 	}
 
-	sa = sigfig(a)
+	sa := sigfig(a)
 	if sa == 0 {
 		// zero
 		a.Exp = 0
@@ -156,7 +147,7 @@
 		return
 	}
 
-	sb = sigfig(b)
+	sb := sigfig(b)
 	if sb == 0 {
 		// zero
 		mpmovefltflt(a, b)
@@ -174,15 +165,11 @@
 }
 
 func mpdivfltflt(a *Mpflt, b *Mpflt) {
-	var sa int
-	var sb int
-	var c Mpflt
-
 	if Mpdebug != 0 /*TypeKind(100016)*/ {
 		fmt.Printf("%v\n / %v\n", Fconv(a, 0), Fconv(b, 0))
 	}
 
-	sb = sigfig(b)
+	sb := sigfig(b)
 	if sb == 0 {
 		// zero and ovfl
 		a.Exp = 0
@@ -193,7 +180,7 @@
 		return
 	}
 
-	sa = sigfig(a)
+	sa := sigfig(a)
 	if sa == 0 {
 		// zero
 		a.Exp = 0
@@ -203,6 +190,7 @@
 	}
 
 	// adjust b to top
+	var c Mpflt
 	mpmovefltflt(&c, b)
 
 	Mpshiftfix(&c.Val, Mpscale)
@@ -219,18 +207,11 @@
 }
 
 func mpgetfltN(a *Mpflt, prec int, bias int) float64 {
-	var s int
-	var i int
-	var e int
-	var minexp int
-	var v uint64
-	var f float64
-
 	if a.Val.Ovf != 0 && nsavederrors+nerrors == 0 {
 		Yyerror("mpgetflt ovf")
 	}
 
-	s = sigfig(a)
+	s := sigfig(a)
 	if s == 0 {
 		return 0
 	}
@@ -252,7 +233,8 @@
 	// pick up the mantissa, a rounding bit, and a tie-breaking bit in a uvlong
 	s = prec + 2
 
-	v = 0
+	v := uint64(0)
+	var i int
 	for i = Mpnorm - 1; s >= Mpscale; i-- {
 		v = v<<Mpscale | uint64(a.Val.A[i])
 		s -= Mpscale
@@ -273,11 +255,11 @@
 	}
 
 	// gradual underflow
-	e = Mpnorm*Mpscale + int(a.Exp) - prec
+	e := Mpnorm*Mpscale + int(a.Exp) - prec
 
-	minexp = bias + 1 - prec + 1
+	minexp := bias + 1 - prec + 1
 	if e < minexp {
-		s = minexp - e
+		s := minexp - e
 		if s > prec+1 {
 			s = prec + 1
 		}
@@ -294,7 +276,7 @@
 	v += v & 1
 	v >>= 2
 
-	f = float64(v)
+	f := float64(v)
 	f = math.Ldexp(f, e)
 
 	if a.Val.Neg != 0 {
@@ -313,15 +295,14 @@
 }
 
 func Mpmovecflt(a *Mpflt, c float64) {
-	var i int
-	var f float64
-	var l int
-
 	if Mpdebug != 0 /*TypeKind(100016)*/ {
 		fmt.Printf("\nconst %g", c)
 	}
 	Mpmovecfix(&a.Val, 0)
 	a.Exp = 0
+	var f float64
+	var l int
+	var i int
 	if c == 0 {
 		goto out
 	}
@@ -333,7 +314,7 @@
 	f, i = math.Frexp(c)
 	a.Exp = int16(i)
 
-	for i = 0; i < 10; i++ {
+	for i := 0; i < 10; i++ {
 		f = f * Mpbase
 		l = int(math.Floor(f))
 		f = f - float64(l)
@@ -357,12 +338,10 @@
 }
 
 func mptestflt(a *Mpflt) int {
-	var s int
-
 	if Mpdebug != 0 /*TypeKind(100016)*/ {
 		fmt.Printf("\n%v?", Fconv(a, 0))
 	}
-	s = sigfig(a)
+	s := sigfig(a)
 	if s != 0 {
 		s = +1
 		if a.Val.Neg != 0 {
diff --git a/src/cmd/internal/gc/obj.go b/src/cmd/internal/gc/obj.go
index afaf87c..27a1811 100644
--- a/src/cmd/internal/gc/obj.go
+++ b/src/cmd/internal/gc/obj.go
@@ -21,13 +21,6 @@
 }
 
 func dumpobj() {
-	var externs *NodeList
-	var tmp *NodeList
-	var arhdr [ArhdrSize]byte
-	var startobj int64
-	var size int64
-	var zero *Sym
-
 	var err error
 	bout, err = obj.Bopenw(outfile)
 	if err != nil {
@@ -36,7 +29,8 @@
 		errorexit()
 	}
 
-	startobj = 0
+	startobj := int64(0)
+	var arhdr [ArhdrSize]byte
 	if writearchive != 0 {
 		obj.Bwritestring(bout, "!<arch>\n")
 		arhdr = [ArhdrSize]byte{}
@@ -49,7 +43,7 @@
 
 	if writearchive != 0 {
 		obj.Bflush(bout)
-		size = obj.Boffset(bout) - startobj
+		size := obj.Boffset(bout) - startobj
 		if size&1 != 0 {
 			obj.Bputc(bout, 0)
 		}
@@ -77,7 +71,7 @@
 
 	fmt.Fprintf(bout, "\n!\n")
 
-	externs = nil
+	externs := (*NodeList)(nil)
 	if externdcl != nil {
 		externs = externdcl.End
 	}
@@ -86,7 +80,7 @@
 	dumptypestructs()
 
 	// Dump extra globals.
-	tmp = externdcl
+	tmp := externdcl
 
 	if externs != nil {
 		externdcl = externs.Next
@@ -94,7 +88,7 @@
 	dumpglobls()
 	externdcl = tmp
 
-	zero = Pkglookup("zerovalue", Runtimepkg)
+	zero := Pkglookup("zerovalue", Runtimepkg)
 	ggloblsym(zero, int32(zerosize), obj.DUPOK|obj.RODATA)
 
 	dumpdata()
@@ -102,7 +96,7 @@
 
 	if writearchive != 0 {
 		obj.Bflush(bout)
-		size = obj.Boffset(bout) - startobj
+		size := obj.Boffset(bout) - startobj
 		if size&1 != 0 {
 			obj.Bputc(bout, 0)
 		}
@@ -117,10 +111,9 @@
 
 func dumpglobls() {
 	var n *Node
-	var l *NodeList
 
 	// add globals
-	for l = externdcl; l != nil; l = l.Next {
+	for l := externdcl; l != nil; l = l.Next {
 		n = l.N
 		if n.Op != ONAME {
 			continue
@@ -140,7 +133,7 @@
 		ggloblnod(n)
 	}
 
-	for l = funcsyms; l != nil; l = l.Next {
+	for l := funcsyms; l != nil; l = l.Next {
 		n = l.N
 		dsymptr(n.Sym, 0, n.Sym.Def.Shortname.Sym, 0)
 		ggloblsym(n.Sym, int32(Widthptr), obj.DUPOK|obj.RODATA)
@@ -156,8 +149,6 @@
 }
 
 func Linksym(s *Sym) *obj.LSym {
-	var p string
-
 	if s == nil {
 		return nil
 	}
@@ -169,7 +160,7 @@
 	} else if s.Linkname != "" {
 		s.Lsym = obj.Linklookup(Ctxt, s.Linkname, 0)
 	} else {
-		p = fmt.Sprintf("%s.%s", s.Pkg.Prefix, s.Name)
+		p := fmt.Sprintf("%s.%s", s.Pkg.Prefix, s.Name)
 		s.Lsym = obj.Linklookup(Ctxt, p, 0)
 	}
 
@@ -208,10 +199,6 @@
 var stringsym_gen int
 
 func stringsym(s string) *Sym {
-	var sym *Sym
-	var off int
-	var n int
-	var m int
 	var tmp struct {
 		lit Strlit
 		buf string
@@ -233,7 +220,7 @@
 		pkg = gostringpkg
 	}
 
-	sym = Pkglookup(namebuf, pkg)
+	sym := Pkglookup(namebuf, pkg)
 
 	// SymUniq flag indicates that data is generated already
 	if sym.Flags&SymUniq != 0 {
@@ -242,14 +229,15 @@
 	sym.Flags |= SymUniq
 	sym.Def = newname(sym)
 
-	off = 0
+	off := 0
 
 	// string header
 	off = dsymptr(sym, off, sym, Widthptr+Widthint)
 	off = duintxx(sym, off, uint64(len(s)), Widthint)
 
 	// string data
-	for n = 0; n < len(s); n += m {
+	var m int
+	for n := 0; n < len(s); n += m {
 		m = 8
 		if m > len(s)-n {
 			m = len(s) - n
@@ -267,18 +255,15 @@
 var slicebytes_gen int
 
 func slicebytes(nam *Node, s string, len int) {
-	var off int
-	var n int
 	var m int
-	var sym *Sym
 
 	slicebytes_gen++
 	namebuf = fmt.Sprintf(".gobytes.%d", slicebytes_gen)
-	sym = Pkglookup(namebuf, localpkg)
+	sym := Pkglookup(namebuf, localpkg)
 	sym.Def = newname(sym)
 
-	off = 0
-	for n = 0; n < len; n += m {
+	off := 0
+	for n := 0; n < len; n += m {
 		m = 8
 		if m > len-n {
 			m = len - n
@@ -298,10 +283,8 @@
 }
 
 func dstringptr(s *Sym, off int, str string) int {
-	var p *obj.Prog
-
 	off = int(Rnd(int64(off), int64(Widthptr)))
-	p = Thearch.Gins(obj.ADATA, nil, nil)
+	p := Thearch.Gins(obj.ADATA, nil, nil)
 	p.From.Type = obj.TYPE_MEM
 	p.From.Name = obj.NAME_EXTERN
 	p.From.Sym = Linksym(s)
@@ -321,9 +304,7 @@
  * gobj.c
  */
 func Datastring(s string, a *obj.Addr) {
-	var sym *Sym
-
-	sym = stringsym(s)
+	sym := stringsym(s)
 	a.Type = obj.TYPE_MEM
 	a.Name = obj.NAME_EXTERN
 	a.Sym = Linksym(sym)
@@ -333,9 +314,7 @@
 }
 
 func datagostring(sval *Strlit, a *obj.Addr) {
-	var sym *Sym
-
-	sym = stringsym(sval.S)
+	sym := stringsym(sval.S)
 	a.Type = obj.TYPE_MEM
 	a.Name = obj.NAME_EXTERN
 	a.Sym = Linksym(sym)
@@ -345,29 +324,24 @@
 }
 
 func dgostringptr(s *Sym, off int, str string) int {
-	var n int
-	var lit *Strlit
-
 	if str == "" {
 		return duintptr(s, off, 0)
 	}
 
-	n = len(str)
-	lit = new(Strlit)
+	n := len(str)
+	lit := new(Strlit)
 	lit.S = str
 	lit.S = lit.S[:n]
 	return dgostrlitptr(s, off, lit)
 }
 
 func dgostrlitptr(s *Sym, off int, lit *Strlit) int {
-	var p *obj.Prog
-
 	if lit == nil {
 		return duintptr(s, off, 0)
 	}
 
 	off = int(Rnd(int64(off), int64(Widthptr)))
-	p = Thearch.Gins(obj.ADATA, nil, nil)
+	p := Thearch.Gins(obj.ADATA, nil, nil)
 	p.From.Type = obj.TYPE_MEM
 	p.From.Name = obj.NAME_EXTERN
 	p.From.Sym = Linksym(s)
@@ -383,9 +357,7 @@
 }
 
 func dsname(s *Sym, off int, t string) int {
-	var p *obj.Prog
-
-	p = Thearch.Gins(obj.ADATA, nil, nil)
+	p := Thearch.Gins(obj.ADATA, nil, nil)
 	p.From.Type = obj.TYPE_MEM
 	p.From.Name = obj.NAME_EXTERN
 	p.From.Offset = int64(off)
@@ -399,11 +371,9 @@
 }
 
 func dsymptr(s *Sym, off int, x *Sym, xoff int) int {
-	var p *obj.Prog
-
 	off = int(Rnd(int64(off), int64(Widthptr)))
 
-	p = Thearch.Gins(obj.ADATA, nil, nil)
+	p := Thearch.Gins(obj.ADATA, nil, nil)
 	p.From.Type = obj.TYPE_MEM
 	p.From.Name = obj.NAME_EXTERN
 	p.From.Sym = Linksym(s)
@@ -420,8 +390,6 @@
 }
 
 func gdata(nam *Node, nr *Node, wid int) {
-	var p *obj.Prog
-
 	if nr.Op == OLITERAL {
 		switch nr.Val.Ctype {
 		case CTCPLX:
@@ -434,19 +402,16 @@
 		}
 	}
 
-	p = Thearch.Gins(obj.ADATA, nam, nr)
+	p := Thearch.Gins(obj.ADATA, nam, nr)
 	p.From3.Type = obj.TYPE_CONST
 	p.From3.Offset = int64(wid)
 }
 
 func gdatacomplex(nam *Node, cval *Mpcplx) {
-	var p *obj.Prog
-	var w int
-
-	w = cplxsubtype(int(nam.Type.Etype))
+	w := cplxsubtype(int(nam.Type.Etype))
 	w = int(Types[w].Width)
 
-	p = Thearch.Gins(obj.ADATA, nam, nil)
+	p := Thearch.Gins(obj.ADATA, nam, nil)
 	p.From3.Type = obj.TYPE_CONST
 	p.From3.Offset = int64(w)
 	p.To.Type = obj.TYPE_FCONST
@@ -461,10 +426,9 @@
 }
 
 func gdatastring(nam *Node, sval *Strlit) {
-	var p *obj.Prog
 	var nod1 Node
 
-	p = Thearch.Gins(obj.ADATA, nam, nil)
+	p := Thearch.Gins(obj.ADATA, nam, nil)
 	Datastring(sval.S, &p.To)
 	p.From3.Type = obj.TYPE_CONST
 	p.From3.Offset = Types[Tptr].Width
diff --git a/src/cmd/internal/gc/order.go b/src/cmd/internal/gc/order.go
index 743ca80..e8744d7 100644
--- a/src/cmd/internal/gc/order.go
+++ b/src/cmd/internal/gc/order.go
@@ -49,10 +49,8 @@
 // Order rewrites fn->nbody to apply the ordering constraints
 // described in the comment at the top of the file.
 func order(fn *Node) {
-	var s string
-
 	if Debug['W'] > 1 {
-		s = fmt.Sprintf("\nbefore order %v", Sconv(fn.Nname.Sym, 0))
+		s := fmt.Sprintf("\nbefore order %v", Sconv(fn.Nname.Sym, 0))
 		dumplist(s, fn.Nbody)
 	}
 
@@ -63,18 +61,14 @@
 // pushes it onto the temp stack, and returns it.
 // If clear is true, ordertemp emits code to zero the temporary.
 func ordertemp(t *Type, order *Order, clear bool) *Node {
-	var var_ *Node
-	var a *Node
-	var l *NodeList
-
-	var_ = temp(t)
+	var_ := temp(t)
 	if clear {
-		a = Nod(OAS, var_, nil)
+		a := Nod(OAS, var_, nil)
 		typecheck(&a, Etop)
 		order.out = list(order.out, a)
 	}
 
-	l = order.free
+	l := order.free
 	if l == nil {
 		l = new(NodeList)
 	}
@@ -98,11 +92,8 @@
 // returns a pointer to the result data instead of taking a pointer
 // to be filled in.)
 func ordercopyexpr(n *Node, t *Type, order *Order, clear int) *Node {
-	var a *Node
-	var var_ *Node
-
-	var_ = ordertemp(t, order, clear != 0)
-	a = Nod(OAS, var_, n)
+	var_ := ordertemp(t, order, clear != 0)
+	a := Nod(OAS, var_, n)
 	typecheck(&a, Etop)
 	order.out = list(order.out, a)
 	return var_
@@ -130,21 +121,17 @@
 //
 // The intended use is to apply to x when rewriting x += y into x = x + y.
 func ordersafeexpr(n *Node, order *Order) *Node {
-	var l *Node
-	var r *Node
-	var a *Node
-
 	switch n.Op {
 	case ONAME,
 		OLITERAL:
 		return n
 
 	case ODOT:
-		l = ordersafeexpr(n.Left, order)
+		l := ordersafeexpr(n.Left, order)
 		if l == n.Left {
 			return n
 		}
-		a = Nod(OXXX, nil, nil)
+		a := Nod(OXXX, nil, nil)
 		*a = *n
 		a.Orig = a
 		a.Left = l
@@ -153,11 +140,11 @@
 
 	case ODOTPTR,
 		OIND:
-		l = ordercheapexpr(n.Left, order)
+		l := ordercheapexpr(n.Left, order)
 		if l == n.Left {
 			return n
 		}
-		a = Nod(OXXX, nil, nil)
+		a := Nod(OXXX, nil, nil)
 		*a = *n
 		a.Orig = a
 		a.Left = l
@@ -166,16 +153,17 @@
 
 	case OINDEX,
 		OINDEXMAP:
+		var l *Node
 		if Isfixedarray(n.Left.Type) {
 			l = ordersafeexpr(n.Left, order)
 		} else {
 			l = ordercheapexpr(n.Left, order)
 		}
-		r = ordercheapexpr(n.Right, order)
+		r := ordercheapexpr(n.Right, order)
 		if l == n.Left && r == n.Right {
 			return n
 		}
-		a = Nod(OXXX, nil, nil)
+		a := Nod(OXXX, nil, nil)
 		*a = *n
 		a.Orig = a
 		a.Left = l
@@ -210,9 +198,7 @@
 // If the original argument *np is not okay, orderaddrtemp creates a tmp, emits
 // tmp = *np, and then sets *np to the tmp variable.
 func orderaddrtemp(np **Node, order *Order) {
-	var n *Node
-
-	n = *np
+	n := *np
 	if isaddrokay(n) {
 		return
 	}
@@ -244,10 +230,9 @@
 // above the mark on the temporary stack, but it does not pop them
 // from the stack.
 func cleantempnopop(mark *NodeList, order *Order, out **NodeList) {
-	var l *NodeList
 	var kill *Node
 
-	for l = order.temp; l != mark; l = l.Next {
+	for l := order.temp; l != mark; l = l.Next {
 		kill = Nod(OVARKILL, l.N, nil)
 		typecheck(&kill, Etop)
 		*out = list(*out, kill)
@@ -271,11 +256,8 @@
 // Orderblock orders the block of statements *l onto a new list,
 // and then replaces *l with that list.
 func orderblock(l **NodeList) {
-	var order Order
-	var mark *NodeList
-
-	order = Order{}
-	mark = marktemp(&order)
+	order := Order{}
+	mark := marktemp(&order)
 	orderstmtlist(*l, &order)
 	cleantemp(mark, &order)
 	*l = order.out
@@ -284,18 +266,14 @@
 // Orderexprinplace orders the side effects in *np and
 // leaves them as the init list of the final *np.
 func orderexprinplace(np **Node, outer *Order) {
-	var n *Node
-	var lp **NodeList
-	var order Order
-
-	n = *np
-	order = Order{}
+	n := *np
+	order := Order{}
 	orderexpr(&n, &order)
 	addinit(&n, order.out)
 
 	// insert new temporaries from order
 	// at head of outer list.
-	lp = &order.temp
+	lp := &order.temp
 
 	for *lp != nil {
 		lp = &(*lp).Next
@@ -309,13 +287,9 @@
 // Orderstmtinplace orders the side effects of the single statement *np
 // and replaces it with the resulting statement list.
 func orderstmtinplace(np **Node) {
-	var n *Node
-	var order Order
-	var mark *NodeList
-
-	n = *np
-	order = Order{}
-	mark = marktemp(&order)
+	n := *np
+	order := Order{}
+	mark := marktemp(&order)
 	orderstmt(n, &order)
 	cleantemp(mark, &order)
 	*np = liststmt(order.out)
@@ -330,13 +304,11 @@
 // Ismulticall reports whether the list l is f() for a multi-value function.
 // Such an f() could appear as the lone argument to a multi-arg function.
 func ismulticall(l *NodeList) bool {
-	var n *Node
-
 	// one arg only
 	if l == nil || l.Next != nil {
 		return false
 	}
-	n = l.N
+	n := l.N
 
 	// must be call
 	switch n.Op {
@@ -356,26 +328,21 @@
 // Copyret emits t1, t2, ... = n, where n is a function call,
 // and then returns the list t1, t2, ....
 func copyret(n *Node, order *Order) *NodeList {
-	var t *Type
-	var tmp *Node
-	var as *Node
-	var l1 *NodeList
-	var l2 *NodeList
-	var tl Iter
-
 	if n.Type.Etype != TSTRUCT || n.Type.Funarg == 0 {
 		Fatal("copyret %v %d", Tconv(n.Type, 0), n.Left.Type.Outtuple)
 	}
 
-	l1 = nil
-	l2 = nil
-	for t = Structfirst(&tl, &n.Type); t != nil; t = structnext(&tl) {
+	l1 := (*NodeList)(nil)
+	l2 := (*NodeList)(nil)
+	var tl Iter
+	var tmp *Node
+	for t := Structfirst(&tl, &n.Type); t != nil; t = structnext(&tl) {
 		tmp = temp(t.Type)
 		l1 = list(l1, tmp)
 		l2 = list(l2, tmp)
 	}
 
-	as = Nod(OAS2, nil, nil)
+	as := Nod(OAS2, nil, nil)
 	as.List = l1
 	as.Rlist = list1(n)
 	typecheck(&as, Etop)
@@ -426,11 +393,6 @@
 // Ordermapassign also inserts these temporaries if needed for
 // calling writebarrierfat with a pointer to n->right.
 func ordermapassign(n *Node, order *Order) {
-	var m *Node
-	var a *Node
-	var l *NodeList
-	var post *NodeList
-
 	switch n.Op {
 	default:
 		Fatal("ordermapassign %v", Oconv(int(n.Op), 0))
@@ -440,9 +402,9 @@
 
 		// We call writebarrierfat only for values > 4 pointers long. See walk.c.
 		if (n.Left.Op == OINDEXMAP || (needwritebarrier(n.Left, n.Right) && n.Left.Type.Width > int64(4*Widthptr))) && !isaddrokay(n.Right) {
-			m = n.Left
+			m := n.Left
 			n.Left = ordertemp(m.Type, order, false)
-			a = Nod(OAS, m, n.Left)
+			a := Nod(OAS, m, n.Left)
 			typecheck(&a, Etop)
 			order.out = list(order.out, a)
 		}
@@ -451,8 +413,10 @@
 		OAS2DOTTYPE,
 		OAS2MAPR,
 		OAS2FUNC:
-		post = nil
-		for l = n.List; l != nil; l = l.Next {
+		post := (*NodeList)(nil)
+		var m *Node
+		var a *Node
+		for l := n.List; l != nil; l = l.Next {
 			if l.N.Op == OINDEXMAP {
 				m = l.N
 				if !istemp(m.Left) {
@@ -477,22 +441,11 @@
 // Temporaries created during the statement are cleaned
 // up using VARKILL instructions as possible.
 func orderstmt(n *Node, order *Order) {
-	var lno int
-	var l *NodeList
-	var t *NodeList
-	var t1 *NodeList
-	var r *Node
-	var tmp1 *Node
-	var tmp2 *Node
-	var np **Node
-	var ch *Type
-	var typ *Type
-
 	if n == nil {
 		return
 	}
 
-	lno = int(setlineno(n))
+	lno := int(setlineno(n))
 
 	orderinit(n, order)
 
@@ -511,7 +464,7 @@
 		OPRINTN,
 		ORECOVER,
 		ORECV:
-		t = marktemp(order)
+		t := marktemp(order)
 		orderexpr(&n.Left, order)
 		orderexpr(&n.Right, order)
 		orderexprlist(n.List, order)
@@ -534,11 +487,11 @@
 	// out map read from map write when l is
 	// a map index expression.
 	case OASOP:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexpr(&n.Left, order)
 		n.Left = ordersafeexpr(n.Left, order)
-		tmp1 = treecopy(n.Left)
+		tmp1 := treecopy(n.Left)
 		if tmp1.Op == OINDEXMAP {
 			tmp1.Etype = 0 // now an rvalue not an lvalue
 		}
@@ -554,10 +507,10 @@
 		// Special: make sure key is addressable,
 	// and make sure OINDEXMAP is not copied out.
 	case OAS2MAPR:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexprlist(n.List, order)
-		r = n.Rlist.N
+		r := n.Rlist.N
 		orderexpr(&r.Left, order)
 		orderexpr(&r.Right, order)
 
@@ -571,7 +524,7 @@
 
 		// Special: avoid copy of func call n->rlist->n.
 	case OAS2FUNC:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexprlist(n.List, order)
 		ordercall(n.Rlist.N, order)
@@ -582,17 +535,17 @@
 	// so that assertI2Tetc can take address of temporary.
 	// No temporary for blank assignment.
 	case OAS2DOTTYPE:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexprlist(n.List, order)
 		orderexpr(&n.Rlist.N.Left, order) // i in i.(T)
 		if isblank(n.List.N) {
 			order.out = list(order.out, n)
 		} else {
-			typ = n.Rlist.N.Type
-			tmp1 = ordertemp(typ, order, haspointers(typ))
+			typ := n.Rlist.N.Type
+			tmp1 := ordertemp(typ, order, haspointers(typ))
 			order.out = list(order.out, n)
-			r = Nod(OAS, n.List.N, tmp1)
+			r := Nod(OAS, n.List.N, tmp1)
 			typecheck(&r, Etop)
 			ordermapassign(r, order)
 			n.List = list(list1(tmp1), n.List.Next.N)
@@ -603,19 +556,20 @@
 		// Special: use temporary variables to hold result,
 	// so that chanrecv can take address of temporary.
 	case OAS2RECV:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexprlist(n.List, order)
 		orderexpr(&n.Rlist.N.Left, order) // arg to recv
-		ch = n.Rlist.N.Left.Type
-		tmp1 = ordertemp(ch.Type, order, haspointers(ch.Type))
+		ch := n.Rlist.N.Left.Type
+		tmp1 := ordertemp(ch.Type, order, haspointers(ch.Type))
+		var tmp2 *Node
 		if !isblank(n.List.Next.N) {
 			tmp2 = ordertemp(n.List.Next.N.Type, order, false)
 		} else {
 			tmp2 = ordertemp(Types[TBOOL], order, false)
 		}
 		order.out = list(order.out, n)
-		r = Nod(OAS, n.List.N, tmp1)
+		r := Nod(OAS, n.List.N, tmp1)
 		typecheck(&r, Etop)
 		ordermapassign(r, order)
 		r = Nod(OAS, n.List.Next.N, tmp2)
@@ -646,7 +600,7 @@
 	case OCALLFUNC,
 		OCALLINTER,
 		OCALLMETH:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		ordercall(n, order)
 		order.out = list(order.out, n)
@@ -655,7 +609,7 @@
 		// Special: order arguments to inner call but not call itself.
 	case ODEFER,
 		OPROC:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		switch n.Left.Op {
 		// Delete will take the address of the key.
@@ -664,8 +618,8 @@
 		case ODELETE:
 			orderexprlist(n.Left.List, order)
 
-			t1 = marktemp(order)
-			np = &n.Left.List.Next.N // map key
+			t1 := marktemp(order)
+			np := &n.Left.List.Next.N // map key
 			*np = ordercopyexpr(*np, (*np).Type, order, 0)
 			poptemp(t1, order)
 
@@ -677,7 +631,7 @@
 		cleantemp(t, order)
 
 	case ODELETE:
-		t = marktemp(order)
+		t := marktemp(order)
 		orderexpr(&n.List.N, order)
 		orderexpr(&n.List.Next.N, order)
 		orderaddrtemp(&n.List.Next.N, order) // map key
@@ -687,10 +641,10 @@
 		// Clean temporaries from condition evaluation at
 	// beginning of loop body and after for statement.
 	case OFOR:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexprinplace(&n.Ntest, order)
-		l = nil
+		l := (*NodeList)(nil)
 		cleantempnopop(t, order, &l)
 		n.Nbody = concat(l, n.Nbody)
 		orderblock(&n.Nbody)
@@ -701,10 +655,10 @@
 		// Clean temporaries from condition at
 	// beginning of both branches.
 	case OIF:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexprinplace(&n.Ntest, order)
-		l = nil
+		l := (*NodeList)(nil)
 		cleantempnopop(t, order, &l)
 		n.Nbody = concat(l, n.Nbody)
 		l = nil
@@ -718,7 +672,7 @@
 		// Special: argument will be converted to interface using convT2E
 	// so make sure it is an addressable temporary.
 	case OPANIC:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexpr(&n.Left, order)
 		if !Isinter(n.Left.Type) {
@@ -736,7 +690,7 @@
 	// which must make a copy to avoid seeing updates made during
 	// the range body. Ranging over an array value is uncommon though.
 	case ORANGE:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexpr(&n.Right, order)
 		switch n.Type.Etype {
@@ -761,7 +715,7 @@
 		// fall through
 		case TCHAN,
 			TSTRING:
-			r = n.Right
+			r := n.Right
 
 			if r.Type.Etype == TSTRING && r.Type != Types[TSTRING] {
 				r = Nod(OCONV, r, nil)
@@ -775,7 +729,7 @@
 		// TODO(rsc): Make tmp = literal expressions reuse tmp.
 		// For maps tmp is just one word so it hardly matters.
 		case TMAP:
-			r = n.Right
+			r := n.Right
 
 			n.Right = ordercopyexpr(r, r.Type, order, 0)
 
@@ -783,7 +737,7 @@
 			n.Alloc = ordertemp(Types[TUINT8], order, true)
 		}
 
-		for l = n.List; l != nil; l = l.Next {
+		for l := n.List; l != nil; l = l.Next {
 			orderexprinplace(&l.N, order)
 		}
 		orderblock(&n.Nbody)
@@ -804,9 +758,12 @@
 	// case (if p were nil, then the timing of the fault would
 	// give this away).
 	case OSELECT:
-		t = marktemp(order)
+		t := marktemp(order)
 
-		for l = n.List; l != nil; l = l.Next {
+		var tmp1 *Node
+		var tmp2 *Node
+		var r *Node
+		for l := n.List; l != nil; l = l.Next {
 			if l.N.Op != OXCASE {
 				Fatal("order select case %v", Oconv(int(l.N.Op), 0))
 			}
@@ -931,7 +888,7 @@
 		// Now that we have accumulated all the temporaries, clean them.
 		// Also insert any ninit queued during the previous loop.
 		// (The temporary cleaning must follow that ninit work.)
-		for l = n.List; l != nil; l = l.Next {
+		for l := n.List; l != nil; l = l.Next {
 			cleantempnopop(t, order, &l.N.Ninit)
 			l.N.Nbody = concat(l.N.Ninit, l.N.Nbody)
 			l.N.Ninit = nil
@@ -942,7 +899,7 @@
 
 		// Special: value being sent is passed as a pointer; make it addressable.
 	case OSEND:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexpr(&n.Left, order)
 		orderexpr(&n.Right, order)
@@ -958,10 +915,10 @@
 	// For now just clean all the temporaries at the end.
 	// In practice that's fine.
 	case OSWITCH:
-		t = marktemp(order)
+		t := marktemp(order)
 
 		orderexpr(&n.Ntest, order)
-		for l = n.List; l != nil; l = l.Next {
+		for l := n.List; l != nil; l = l.Next {
 			if l.N.Op != OXCASE {
 				Fatal("order switch case %v", Oconv(int(l.N.Op), 0))
 			}
@@ -994,20 +951,12 @@
 // Orderexpr orders a single expression, appending side
 // effects to order->out as needed.
 func orderexpr(np **Node, order *Order) {
-	var n *Node
-	var mark *NodeList
-	var l *NodeList
-	var t *Type
-	var lno int
-	var haslit bool
-	var hasbyte bool
-
-	n = *np
+	n := *np
 	if n == nil {
 		return
 	}
 
-	lno = int(setlineno(n))
+	lno := int(setlineno(n))
 	orderinit(n, order)
 
 	switch n.Op {
@@ -1024,7 +973,7 @@
 		orderexprlist(n.List, order)
 
 		if count(n.List) > 5 {
-			t = typ(TARRAY)
+			t := typ(TARRAY)
 			t.Bound = int64(count(n.List))
 			t.Type = Types[TSTRING]
 			n.Alloc = ordertemp(t, order, false)
@@ -1037,16 +986,16 @@
 		// Otherwise if all other arguments are empty strings,
 		// concatstrings will return the reference to the temp string
 		// to the caller.
-		hasbyte = false
+		hasbyte := false
 
-		haslit = false
-		for l = n.List; l != nil; l = l.Next {
+		haslit := false
+		for l := n.List; l != nil; l = l.Next {
 			hasbyte = hasbyte || l.N.Op == OARRAYBYTESTR
 			haslit = haslit || l.N.Op == OLITERAL && len(l.N.Val.U.Sval.S) != 0
 		}
 
 		if haslit && hasbyte {
-			for l = n.List; l != nil; l = l.Next {
+			for l := n.List; l != nil; l = l.Next {
 				if l.N.Op == OARRAYBYTESTR {
 					l.N.Op = OARRAYBYTESTRTMP
 				}
@@ -1105,13 +1054,13 @@
 
 	case OANDAND,
 		OOROR:
-		mark = marktemp(order)
+		mark := marktemp(order)
 		orderexpr(&n.Left, order)
 
 		// Clean temporaries from first branch at beginning of second.
 		// Leave them on the stack so that they can be killed in the outer
 		// context in case the short circuit is taken.
-		l = nil
+		l := (*NodeList)(nil)
 
 		cleantempnopop(mark, order, &l)
 		n.Right.Ninit = concat(l, n.Right.Ninit)
@@ -1168,7 +1117,7 @@
 		ONE:
 		orderexpr(&n.Left, order)
 		orderexpr(&n.Right, order)
-		t = n.Left.Type
+		t := n.Left.Type
 		if t.Etype == TSTRUCT || Isfixedarray(t) {
 			// for complex comparisons, we need both args to be
 			// addressable so we can pass them to the runtime.
diff --git a/src/cmd/internal/gc/pgen.go b/src/cmd/internal/gc/pgen.go
index c4c0dd4..cb6cb5b 100644
--- a/src/cmd/internal/gc/pgen.go
+++ b/src/cmd/internal/gc/pgen.go
@@ -20,13 +20,11 @@
 
 func makefuncdatasym(namefmt string, funcdatakind int64) *Sym {
 	var nod Node
-	var pnod *Node
-	var sym *Sym
 
 	namebuf = fmt.Sprintf(namefmt, makefuncdatasym_nsym)
 	makefuncdatasym_nsym++
-	sym = Lookup(namebuf)
-	pnod = newname(sym)
+	sym := Lookup(namebuf)
+	pnod := newname(sym)
 	pnod.Class = PEXTERN
 	Nodconst(&nod, Types[TINT32], funcdatakind)
 	Thearch.Gins(obj.AFUNCDATA, &nod, pnod)
@@ -115,9 +113,7 @@
 }
 
 func removevardef(firstp *obj.Prog) {
-	var p *obj.Prog
-
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		for p.Link != nil && (p.Link.As == obj.AVARDEF || p.Link.As == obj.AVARKILL) {
 			p.Link = p.Link.Link
 		}
@@ -130,41 +126,31 @@
 }
 
 func gcsymdup(s *Sym) {
-	var ls *obj.LSym
-	var lo uint64
-	var hi uint64
-
-	ls = Linksym(s)
+	ls := Linksym(s)
 	if len(ls.R) > 0 {
 		Fatal("cannot rosymdup %s with relocations", ls.Name)
 	}
 	var d MD5
 	md5reset(&d)
 	md5write(&d, ls.P, len(ls.P))
-	lo = md5sum(&d, &hi)
+	var hi uint64
+	lo := md5sum(&d, &hi)
 	ls.Name = fmt.Sprintf("gclocals·%016x%016x", lo, hi)
 	ls.Dupok = 1
 }
 
 func emitptrargsmap() {
-	var nptr int
-	var nbitmap int
-	var j int
-	var off int
-	var xoffset int64
-	var bv *Bvec
-	var sym *Sym
+	sym := Lookup(fmt.Sprintf("%s.args_stackmap", Curfn.Nname.Sym.Name))
 
-	sym = Lookup(fmt.Sprintf("%s.args_stackmap", Curfn.Nname.Sym.Name))
-
-	nptr = int(Curfn.Type.Argwid / int64(Widthptr))
-	bv = bvalloc(int32(nptr) * 2)
-	nbitmap = 1
+	nptr := int(Curfn.Type.Argwid / int64(Widthptr))
+	bv := bvalloc(int32(nptr) * 2)
+	nbitmap := 1
 	if Curfn.Type.Outtuple > 0 {
 		nbitmap = 2
 	}
-	off = duint32(sym, 0, uint32(nbitmap))
+	off := duint32(sym, 0, uint32(nbitmap))
 	off = duint32(sym, off, uint32(bv.n))
+	var xoffset int64
 	if Curfn.Type.Thistuple > 0 {
 		xoffset = 0
 		twobitwalktype1(getthisx(Curfn.Type), &xoffset, bv)
@@ -175,13 +161,13 @@
 		twobitwalktype1(getinargx(Curfn.Type), &xoffset, bv)
 	}
 
-	for j = 0; int32(j) < bv.n; j += 32 {
+	for j := 0; int32(j) < bv.n; j += 32 {
 		off = duint32(sym, off, bv.b[j/32])
 	}
 	if Curfn.Type.Outtuple > 0 {
 		xoffset = 0
 		twobitwalktype1(getoutargx(Curfn.Type), &xoffset, bv)
-		for j = 0; int32(j) < bv.n; j += 32 {
+		for j := 0; int32(j) < bv.n; j += 32 {
 			off = duint32(sym, off, bv.b[j/32])
 		}
 	}
@@ -198,9 +184,6 @@
 // the top of the stack and increasing in size.
 // Non-autos sort on offset.
 func cmpstackvar(a *Node, b *Node) int {
-	var ap int
-	var bp int
-
 	if a.Class != b.Class {
 		if a.Class == PAUTO {
 			return +1
@@ -222,8 +205,8 @@
 		return int(b.Used) - int(a.Used)
 	}
 
-	ap = bool2int(haspointers(a.Type))
-	bp = bool2int(haspointers(b.Type))
+	ap := bool2int(haspointers(a.Type))
+	bp := bool2int(haspointers(b.Type))
 	if ap != bp {
 		return bp - ap
 	}
@@ -246,10 +229,6 @@
 
 // TODO(lvd) find out where the PAUTO/OLITERAL nodes come from.
 func allocauto(ptxt *obj.Prog) {
-	var ll *NodeList
-	var n *Node
-	var w int64
-
 	Stksize = 0
 	stkptrsize = 0
 
@@ -258,7 +237,7 @@
 	}
 
 	// Mark the PAUTO's unused.
-	for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
+	for ll := Curfn.Dcl; ll != nil; ll = ll.Next {
 		if ll.N.Class == PAUTO {
 			ll.N.Used = 0
 		}
@@ -269,9 +248,9 @@
 	listsort(&Curfn.Dcl, cmpstackvar)
 
 	// Unused autos are at the end, chop 'em off.
-	ll = Curfn.Dcl
+	ll := Curfn.Dcl
 
-	n = ll.N
+	n := ll.N
 	if n.Class == PAUTO && n.Op == ONAME && n.Used == 0 {
 		// No locals used at all
 		Curfn.Dcl = nil
@@ -280,7 +259,7 @@
 		return
 	}
 
-	for ll = Curfn.Dcl; ll.Next != nil; ll = ll.Next {
+	for ll := Curfn.Dcl; ll.Next != nil; ll = ll.Next {
 		n = ll.Next.N
 		if n.Class == PAUTO && n.Op == ONAME && n.Used == 0 {
 			ll.Next = nil
@@ -290,7 +269,8 @@
 	}
 
 	// Reassign stack offsets of the locals that are still there.
-	for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
+	var w int64
+	for ll := Curfn.Dcl; ll != nil; ll = ll.Next {
 		n = ll.N
 		if n.Class != PAUTO || n.Op != ONAME {
 			continue
@@ -323,7 +303,7 @@
 	fixautoused(ptxt)
 
 	// The debug information needs accurate offsets on the symbols.
-	for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
+	for ll := Curfn.Dcl; ll != nil; ll = ll.Next {
 		if ll.N.Class != PAUTO || ll.N.Op != ONAME {
 			continue
 		}
@@ -341,10 +321,9 @@
 }
 
 func movelargefn(fn *Node) {
-	var l *NodeList
 	var n *Node
 
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		n = l.N
 		if n.Class == PAUTO && n.Type != nil && n.Type.Width > MaxStackVarSize {
 			addrescapes(n)
@@ -353,8 +332,6 @@
 }
 
 func Cgen_checknil(n *Node) {
-	var reg Node
-
 	if Disable_checknil != 0 {
 		return
 	}
@@ -366,6 +343,7 @@
 	}
 
 	if ((Thearch.Thechar == '5' || Thearch.Thechar == '9') && n.Op != OREGISTER) || n.Addable == 0 || n.Op == OLITERAL {
+		var reg Node
 		Thearch.Regalloc(&reg, Types[Tptr], n)
 		Thearch.Cgen(n, &reg)
 		Thearch.Gins(obj.ACHECKNIL, &reg, nil)
@@ -380,20 +358,6 @@
  * ggen.c
  */
 func compile(fn *Node) {
-	var pl *obj.Plist
-	var nod1 Node
-	var n *Node
-	var ptxt *obj.Prog
-	var p *obj.Prog
-	var lno int32
-	var t *Type
-	var save Iter
-	var oldstksize int64
-	var l *NodeList
-	var nam *Node
-	var gcargs *Sym
-	var gclocals *Sym
-
 	if Newproc == nil {
 		Newproc = Sysfunc("newproc")
 		Deferproc = Sysfunc("deferproc")
@@ -403,11 +367,20 @@
 		throwreturn = Sysfunc("throwreturn")
 	}
 
-	lno = setlineno(fn)
+	lno := setlineno(fn)
 
 	Curfn = fn
 	dowidth(Curfn.Type)
 
+	var oldstksize int64
+	var nod1 Node
+	var ptxt *obj.Prog
+	var pl *obj.Plist
+	var p *obj.Prog
+	var n *Node
+	var nam *Node
+	var gcargs *Sym
+	var gclocals *Sym
 	if fn.Nbody == nil {
 		if pure_go != 0 || strings.HasPrefix(fn.Nname.Sym.Name, "init.") {
 			Yyerror("missing function body", fn)
@@ -428,7 +401,8 @@
 
 	if Curfn.Type.Outnamed != 0 {
 		// add clearing of the output parameters
-		t = Structfirst(&save, Getoutarg(Curfn.Type))
+		var save Iter
+		t := Structfirst(&save, Getoutarg(Curfn.Type))
 
 		for t != nil {
 			if t.Nname != nil {
@@ -501,11 +475,11 @@
 	gcargs = makefuncdatasym("gcargs·%d", obj.FUNCDATA_ArgsPointerMaps)
 	gclocals = makefuncdatasym("gclocals·%d", obj.FUNCDATA_LocalsPointerMaps)
 
-	for t = Curfn.Paramfld; t != nil; t = t.Down {
+	for t := Curfn.Paramfld; t != nil; t = t.Down {
 		gtrack(tracksym(t.Type))
 	}
 
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		n = l.N
 		if n.Op != ONAME { // might be OTYPE or OLITERAL
 			continue
diff --git a/src/cmd/internal/gc/plive.go b/src/cmd/internal/gc/plive.go
index 73f6086..99654c5 100644
--- a/src/cmd/internal/gc/plive.go
+++ b/src/cmd/internal/gc/plive.go
@@ -61,9 +61,7 @@
 }
 
 func xmalloc(size uint32) interface{} {
-	var result interface{}
-
-	result = make([]byte, size)
+	result := (interface{})(make([]byte, size))
 	if result == nil {
 		Fatal("malloc failed")
 	}
@@ -72,12 +70,10 @@
 
 // Constructs a new basic block containing a single instruction.
 func newblock(prog *obj.Prog) *BasicBlock {
-	var result *BasicBlock
-
 	if prog == nil {
 		Fatal("newblock: prog cannot be nil")
 	}
-	result = new(BasicBlock)
+	result := new(BasicBlock)
 	result.rpo = -1
 	result.mark = UNVISITED
 	result.first = prog
@@ -111,9 +107,6 @@
 // stream.  Any control flow, such as branches or fall throughs, that target the
 // existing instruction are adjusted to target the new instruction.
 func splicebefore(lv *Liveness, bb *BasicBlock, prev *obj.Prog, curr *obj.Prog) {
-	var next *obj.Prog
-	var tmp obj.Prog
-
 	// There may be other instructions pointing at curr,
 	// and we want them to now point at prev. Instead of
 	// trying to find all such instructions, swap the contents
@@ -121,14 +114,14 @@
 	// The "opt" field is the backward link in the linked list.
 
 	// Overwrite curr's data with prev, but keep the list links.
-	tmp = *curr
+	tmp := *curr
 
 	*curr = *prev
 	curr.Opt = tmp.Opt
 	curr.Link = tmp.Link
 
 	// Overwrite prev (now next) with curr's old data.
-	next = prev
+	next := prev
 
 	*next = tmp
 	next.Opt = nil
@@ -151,27 +144,25 @@
 // A pretty printer for basic blocks.
 func printblock(bb *BasicBlock) {
 	var pred *BasicBlock
-	var succ *BasicBlock
-	var prog *obj.Prog
-	var i int
 
 	fmt.Printf("basic block %d\n", bb.rpo)
 	fmt.Printf("\tpred:")
-	for i = 0; i < len(bb.pred); i++ {
+	for i := 0; i < len(bb.pred); i++ {
 		pred = bb.pred[i]
 		fmt.Printf(" %d", pred.rpo)
 	}
 
 	fmt.Printf("\n")
 	fmt.Printf("\tsucc:")
-	for i = 0; i < len(bb.succ); i++ {
+	var succ *BasicBlock
+	for i := 0; i < len(bb.succ); i++ {
 		succ = bb.succ[i]
 		fmt.Printf(" %d", succ.rpo)
 	}
 
 	fmt.Printf("\n")
 	fmt.Printf("\tprog:\n")
-	for prog = bb.first; ; prog = prog.Link {
+	for prog := bb.first; ; prog = prog.Link {
 		fmt.Printf("\t\t%v\n", prog)
 		if prog == bb.last {
 			break
@@ -195,11 +186,8 @@
 // Collects and returns and array of Node*s for functions arguments and local
 // variables.
 func getvariables(fn *Node) []*Node {
-	var result []*Node
-	var ll *NodeList
-
-	result = make([]*Node, 0, 0)
-	for ll = fn.Dcl; ll != nil; ll = ll.Next {
+	result := make([]*Node, 0, 0)
+	for ll := fn.Dcl; ll != nil; ll = ll.Next {
 		if ll.N.Op == ONAME {
 			// In order for GODEBUG=gcdead=1 to work, each bitmap needs
 			// to contain information about all variables covered by the bitmap.
@@ -244,9 +232,8 @@
 // A pretty printer for control flow graphs.  Takes an array of BasicBlock*s.
 func printcfg(cfg []*BasicBlock) {
 	var bb *BasicBlock
-	var i int32
 
-	for i = 0; i < int32(len(cfg)); i++ {
+	for i := int32(0); i < int32(len(cfg)); i++ {
 		bb = cfg[i]
 		printblock(bb)
 	}
@@ -256,10 +243,9 @@
 // standard algorithm.  Unconnected blocks will not be affected.
 func reversepostorder(root *BasicBlock, rpo *int32) {
 	var bb *BasicBlock
-	var i int
 
 	root.mark = VISITED
-	for i = 0; i < len(root.succ); i++ {
+	for i := 0; i < len(root.succ); i++ {
 		bb = root.succ[i]
 		if bb.mark == UNVISITED {
 			reversepostorder(bb, rpo)
@@ -299,8 +285,6 @@
 var isselectcommcasecall_names [5]*obj.LSym
 
 func isselectcommcasecall(prog *obj.Prog) bool {
-	var i int32
-
 	if isselectcommcasecall_names[0] == nil {
 		isselectcommcasecall_names[0] = Linksym(Pkglookup("selectsend", Runtimepkg))
 		isselectcommcasecall_names[1] = Linksym(Pkglookup("selectrecv", Runtimepkg))
@@ -308,7 +292,7 @@
 		isselectcommcasecall_names[3] = Linksym(Pkglookup("selectdefault", Runtimepkg))
 	}
 
-	for i = 0; isselectcommcasecall_names[i] != nil; i++ {
+	for i := int32(0); isselectcommcasecall_names[i] != nil; i++ {
 		if iscall(prog, isselectcommcasecall_names[i]) {
 			return true
 		}
@@ -352,10 +336,9 @@
 // are implicit successors of the runtime·selectgo call node.  The goal of this
 // analysis is to add these missing edges to complete the control flow graph.
 func addselectgosucc(selectgo *BasicBlock) {
-	var pred *BasicBlock
 	var succ *BasicBlock
 
-	pred = selectgo
+	pred := selectgo
 	for {
 		if len(pred.pred) == 0 {
 			Fatal("selectgo does not have a newselect")
@@ -392,9 +375,8 @@
 // array of BasicBlock*s containing selectgo calls.
 func fixselectgo(selectgo []*BasicBlock) {
 	var bb *BasicBlock
-	var i int32
 
-	for i = 0; i < int32(len(selectgo)); i++ {
+	for i := int32(0); i < int32(len(selectgo)); i++ {
 		bb = selectgo[i]
 		addselectgosucc(bb)
 	}
@@ -406,33 +388,25 @@
 // array of BasicBlock*s in control flow graph form (basic blocks ordered by
 // their RPO number).
 func newcfg(firstp *obj.Prog) []*BasicBlock {
-	var p *obj.Prog
-	var prev *obj.Prog
-	var bb *BasicBlock
-	var cfg []*BasicBlock
-	var selectgo []*BasicBlock
-	var i int32
-	var rpo int32
-
 	// Reset the opt field of each prog to nil.  In the first and second
 	// passes, instructions that are labels temporarily use the opt field to
 	// point to their basic block.  In the third pass, the opt field reset
 	// to point to the predecessor of an instruction in its basic block.
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		p.Opt = nil
 	}
 
 	// Allocate an array to remember where we have seen selectgo calls.
 	// These blocks will be revisited to add successor control flow edges.
-	selectgo = make([]*BasicBlock, 0, 0)
+	selectgo := make([]*BasicBlock, 0, 0)
 
 	// Loop through all instructions identifying branch targets
 	// and fall-throughs and allocate basic blocks.
-	cfg = make([]*BasicBlock, 0, 0)
+	cfg := make([]*BasicBlock, 0, 0)
 
-	bb = newblock(firstp)
+	bb := newblock(firstp)
 	cfg = append(cfg, bb)
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		if p.To.Type == obj.TYPE_BRANCH {
 			if p.To.U.Branch == nil {
 				Fatal("prog branch to nil")
@@ -458,7 +432,8 @@
 	// Loop through all basic blocks maximally growing the list of
 	// contained instructions until a label is reached.  Add edges
 	// for branches and fall-through instructions.
-	for i = 0; i < int32(len(cfg)); i++ {
+	var p *obj.Prog
+	for i := int32(0); i < int32(len(cfg)); i++ {
 		bb = cfg[i]
 		for p = bb.last; p != nil; p = p.Link {
 			if p.Opt != nil && p != bb.last {
@@ -492,7 +467,8 @@
 
 	// Add back links so the instructions in a basic block can be traversed
 	// backward.  This is the final state of the instruction opt field.
-	for i = 0; i < int32(len(cfg)); i++ {
+	var prev *obj.Prog
+	for i := int32(0); i < int32(len(cfg)); i++ {
 		bb = cfg[i]
 		p = bb.first
 		prev = nil
@@ -513,13 +489,13 @@
 
 	// Find a depth-first order and assign a depth-first number to
 	// all basic blocks.
-	for i = 0; i < int32(len(cfg)); i++ {
+	for i := int32(0); i < int32(len(cfg)); i++ {
 		bb = cfg[i]
 		bb.mark = UNVISITED
 	}
 
 	bb = cfg[0]
-	rpo = int32(len(cfg))
+	rpo := int32(len(cfg))
 	reversepostorder(bb, &rpo)
 
 	// Sort the basic blocks by their depth first number.  The
@@ -544,20 +520,15 @@
 // Frees a control flow graph (an array of BasicBlock*s) and all of its leaf
 // data structures.
 func freecfg(cfg []*BasicBlock) {
-	var bb *BasicBlock
-	var bb0 *BasicBlock
-	var p *obj.Prog
-	var i int32
-	var n int32
-
-	n = int32(len(cfg))
+	n := int32(len(cfg))
 	if n > 0 {
-		bb0 = cfg[0]
-		for p = bb0.first; p != nil; p = p.Link {
+		bb0 := cfg[0]
+		for p := bb0.first; p != nil; p = p.Link {
 			p.Opt = nil
 		}
 
-		for i = 0; i < n; i++ {
+		var bb *BasicBlock
+		for i := int32(0); i < n; i++ {
 			bb = cfg[i]
 			freeblock(bb)
 		}
@@ -586,10 +557,6 @@
 // initialization.
 func progeffects(prog *obj.Prog, vars []*Node, uevar *Bvec, varkill *Bvec, avarinit *Bvec) {
 	var info ProgInfo
-	var from *obj.Addr
-	var to *obj.Addr
-	var node *Node
-	var i int32
 
 	bvresetall(uevar)
 	bvresetall(varkill)
@@ -607,7 +574,8 @@
 		// all the parameters for correctness, and similarly it must not
 		// read the out arguments - they won't be set until the new
 		// function runs.
-		for i = 0; i < int32(len(vars)); i++ {
+		var node *Node
+		for i := int32(0); i < int32(len(vars)); i++ {
 			node = vars[i]
 			switch node.Class &^ PHEAP {
 			case PPARAM:
@@ -634,7 +602,8 @@
 	if prog.As == obj.ATEXT {
 		// A text instruction marks the entry point to a function and
 		// the definition point of all in arguments.
-		for i = 0; i < int32(len(vars)); i++ {
+		var node *Node
+		for i := int32(0); i < int32(len(vars)); i++ {
 			node = vars[i]
 			switch node.Class &^ PHEAP {
 			case PPARAM:
@@ -649,7 +618,7 @@
 	}
 
 	if info.Flags&(LeftRead|LeftWrite|LeftAddr) != 0 {
-		from = &prog.From
+		from := &prog.From
 		if from.Node != nil && from.Sym != nil && ((from.Node).(*Node)).Curfn == Curfn {
 			switch ((from.Node).(*Node)).Class &^ PHEAP {
 			case PAUTO,
@@ -680,7 +649,7 @@
 
 Next:
 	if info.Flags&(RightRead|RightWrite|RightAddr) != 0 {
-		to = &prog.To
+		to := &prog.To
 		if to.Node != nil && to.Sym != nil && ((to.Node).(*Node)).Curfn == Curfn {
 			switch ((to.Node).(*Node)).Class &^ PHEAP {
 			case PAUTO,
@@ -729,18 +698,13 @@
 // liveness computation.  The cfg argument is an array of BasicBlock*s and the
 // vars argument is an array of Node*s.
 func newliveness(fn *Node, ptxt *obj.Prog, cfg []*BasicBlock, vars []*Node) *Liveness {
-	var result *Liveness
-	var i int32
-	var nblocks int32
-	var nvars int32
-
-	result = new(Liveness)
+	result := new(Liveness)
 	result.fn = fn
 	result.ptxt = ptxt
 	result.cfg = cfg
 	result.vars = vars
 
-	nblocks = int32(len(cfg))
+	nblocks := int32(len(cfg))
 	result.uevar = make([]*Bvec, nblocks)
 	result.varkill = make([]*Bvec, nblocks)
 	result.livein = make([]*Bvec, nblocks)
@@ -749,8 +713,8 @@
 	result.avarinitany = make([]*Bvec, nblocks)
 	result.avarinitall = make([]*Bvec, nblocks)
 
-	nvars = int32(len(vars))
-	for i = 0; i < nblocks; i++ {
+	nvars := int32(len(vars))
+	for i := int32(0); i < nblocks; i++ {
 		result.uevar[i] = bvalloc(nvars)
 		result.varkill[i] = bvalloc(nvars)
 		result.livein[i] = bvalloc(nvars)
@@ -767,19 +731,17 @@
 
 // Frees the liveness structure and all of its leaf data structures.
 func freeliveness(lv *Liveness) {
-	var i int32
-
 	if lv == nil {
 		Fatal("freeliveness: cannot free nil")
 	}
 
-	for i = 0; i < int32(len(lv.livepointers)); i++ {
+	for i := int32(0); i < int32(len(lv.livepointers)); i++ {
 	}
 
-	for i = 0; i < int32(len(lv.argslivepointers)); i++ {
+	for i := int32(0); i < int32(len(lv.argslivepointers)); i++ {
 	}
 
-	for i = 0; i < int32(len(lv.cfg)); i++ {
+	for i := int32(0); i < int32(len(lv.cfg)); i++ {
 	}
 }
 
@@ -798,14 +760,11 @@
 // addresses to avoid confusing the C like conventions used in the node variable
 // names.
 func printnode(node *Node) {
-	var p string
-	var a string
-
-	p = ""
+	p := ""
 	if haspointers(node.Type) {
 		p = "^"
 	}
-	a = ""
+	a := ""
 	if node.Addrtaken != 0 {
 		a = "@"
 	}
@@ -814,10 +773,8 @@
 
 // Pretty print a list of variables.  The vars argument is an array of Node*s.
 func printvars(name string, bv *Bvec, vars []*Node) {
-	var i int32
-
 	fmt.Printf("%s:", name)
-	for i = 0; i < int32(len(vars)); i++ {
+	for i := int32(0); i < int32(len(vars)); i++ {
 		if bvget(bv, i) != 0 {
 			printnode(vars[i])
 		}
@@ -829,16 +786,11 @@
 // analysis.
 func livenessprintblock(lv *Liveness, bb *BasicBlock) {
 	var pred *BasicBlock
-	var succ *BasicBlock
-	var prog *obj.Prog
-	var live *Bvec
-	var i int
-	var pos int32
 
 	fmt.Printf("basic block %d\n", bb.rpo)
 
 	fmt.Printf("\tpred:")
-	for i = 0; i < len(bb.pred); i++ {
+	for i := 0; i < len(bb.pred); i++ {
 		pred = bb.pred[i]
 		fmt.Printf(" %d", pred.rpo)
 	}
@@ -846,7 +798,8 @@
 	fmt.Printf("\n")
 
 	fmt.Printf("\tsucc:")
-	for i = 0; i < len(bb.succ); i++ {
+	var succ *BasicBlock
+	for i := 0; i < len(bb.succ); i++ {
 		succ = bb.succ[i]
 		fmt.Printf(" %d", succ.rpo)
 	}
@@ -862,7 +815,9 @@
 	printvars("\tavarinitall", lv.avarinitall[bb.rpo], []*Node(lv.vars))
 
 	fmt.Printf("\tprog:\n")
-	for prog = bb.first; ; prog = prog.Link {
+	var live *Bvec
+	var pos int32
+	for prog := bb.first; ; prog = prog.Link {
 		fmt.Printf("\t\t%v", prog)
 		if prog.As == obj.APCDATA && prog.From.Offset == obj.PCDATA_StackMapIndex {
 			pos = int32(prog.To.Offset)
@@ -882,18 +837,15 @@
 // liveness analysis.
 func livenessprintcfg(lv *Liveness) {
 	var bb *BasicBlock
-	var i int32
 
-	for i = 0; i < int32(len(lv.cfg)); i++ {
+	for i := int32(0); i < int32(len(lv.cfg)); i++ {
 		bb = lv.cfg[i]
 		livenessprintblock(lv, bb)
 	}
 }
 
 func checkauto(fn *Node, p *obj.Prog, n *Node) {
-	var l *NodeList
-
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		if l.N.Op == ONAME && l.N.Class == PAUTO && l.N == n {
 			return
 		}
@@ -905,21 +857,19 @@
 	}
 
 	fmt.Printf("checkauto %v: %v (%p; class=%d) not found in %v\n", Nconv(Curfn, 0), Nconv(n, 0), n, n.Class, p)
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		fmt.Printf("\t%v (%p; class=%d)\n", Nconv(l.N, 0), l.N, l.N.Class)
 	}
 	Yyerror("checkauto: invariant lost")
 }
 
 func checkparam(fn *Node, p *obj.Prog, n *Node) {
-	var l *NodeList
-	var a *Node
-	var class int
-
 	if isfunny(n) {
 		return
 	}
-	for l = fn.Dcl; l != nil; l = l.Next {
+	var a *Node
+	var class int
+	for l := fn.Dcl; l != nil; l = l.Next {
 		a = l.N
 		class = int(a.Class) &^ PHEAP
 		if a.Op == ONAME && (class == PPARAM || class == PPARAMOUT) && a == n {
@@ -928,7 +878,7 @@
 	}
 
 	fmt.Printf("checkparam %v: %v (%p; class=%d) not found in %v\n", Nconv(Curfn, 0), Nconv(n, 0), n, n.Class, p)
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		fmt.Printf("\t%v (%p; class=%d)\n", Nconv(l.N, 0), l.N, l.N.Class)
 	}
 	Yyerror("checkparam: invariant lost")
@@ -955,13 +905,11 @@
 // nodes and there are special cases to skip over that stuff.  The analysis will
 // fail if this invariant blindly changes.
 func checkptxt(fn *Node, firstp *obj.Prog) {
-	var p *obj.Prog
-
 	if debuglive == 0 {
 		return
 	}
 
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		if false {
 			fmt.Printf("analyzing '%v'\n", p)
 		}
@@ -976,11 +924,6 @@
 // the same type t. On https://rsc.googlecode.com/hg/testdata/slow.go, twobitwalktype1
 // accounts for 40% of the 6g execution time.
 func twobitwalktype1(t *Type, xoffset *int64, bv *Bvec) {
-	var fieldoffset int64
-	var i int64
-	var o int64
-	var t1 *Type
-
 	if t.Align > 0 && *xoffset&int64(t.Align-1) != 0 {
 		Fatal("twobitwalktype1: invalid initial alignment, %v", Tconv(t, 0))
 	}
@@ -1002,7 +945,7 @@
 		TFLOAT64,
 		TCOMPLEX64,
 		TCOMPLEX128:
-		for i = 0; i < t.Width; i++ {
+		for i := int64(0); i < t.Width; i++ {
 			bvset(bv, int32(((*xoffset+i)/int64(Widthptr))*obj.BitsPerPointer)) // 1 = live scalar (BitsScalar)
 		}
 
@@ -1053,14 +996,15 @@
 			bvset(bv, int32((*xoffset/int64(Widthptr))*obj.BitsPerPointer+1)) // 2 = live ptr in first slot (BitsPointer)
 			*xoffset += t.Width
 		} else {
-			for i = 0; i < t.Bound; i++ {
+			for i := int64(0); i < t.Bound; i++ {
 				twobitwalktype1(t.Type, xoffset, bv)
 			}
 		}
 
 	case TSTRUCT:
-		o = 0
-		for t1 = t.Type; t1 != nil; t1 = t1.Down {
+		o := int64(0)
+		var fieldoffset int64
+		for t1 := t.Type; t1 != nil; t1 = t1.Down {
 			fieldoffset = t1.Width
 			*xoffset += fieldoffset - o
 			twobitwalktype1(t1.Type, xoffset, bv)
@@ -1089,12 +1033,9 @@
 // argument is an array of Node*s.
 func twobitlivepointermap(lv *Liveness, liveout *Bvec, vars []*Node, args *Bvec, locals *Bvec) {
 	var node *Node
-	var thisargtype *Type
-	var inargtype *Type
 	var xoffset int64
-	var i int32
 
-	for i = 0; ; i++ {
+	for i := int32(0); ; i++ {
 		i = int32(bvnext(liveout, i))
 		if i < 0 {
 			break
@@ -1116,14 +1057,14 @@
 	// If the receiver or arguments are unnamed, they will be omitted
 	// from the list above. Preserve those values - even though they are unused -
 	// in order to keep their addresses live for use in stack traces.
-	thisargtype = getthisx(lv.fn.Type)
+	thisargtype := getthisx(lv.fn.Type)
 
 	if thisargtype != nil {
 		xoffset = 0
 		twobitwalktype1(thisargtype, &xoffset, args)
 	}
 
-	inargtype = getinargx(lv.fn.Type)
+	inargtype := getinargx(lv.fn.Type)
 	if inargtype != nil {
 		xoffset = 0
 		twobitwalktype1(inargtype, &xoffset, args)
@@ -1132,9 +1073,7 @@
 
 // Construct a disembodied instruction.
 func unlinkedprog(as int) *obj.Prog {
-	var p *obj.Prog
-
-	p = Ctxt.NewProg()
+	p := Ctxt.NewProg()
 	Clearp(p)
 	p.As = int16(as)
 	return p
@@ -1145,11 +1084,10 @@
 func newpcdataprog(prog *obj.Prog, index int32) *obj.Prog {
 	var from Node
 	var to Node
-	var pcdata *obj.Prog
 
 	Nodconst(&from, Types[TINT32], obj.PCDATA_StackMapIndex)
 	Nodconst(&to, Types[TINT32], int64(index))
-	pcdata = unlinkedprog(obj.APCDATA)
+	pcdata := unlinkedprog(obj.APCDATA)
 	pcdata.Lineno = prog.Lineno
 	Naddr(&from, &pcdata.From, 0)
 	Naddr(&to, &pcdata.To, 0)
@@ -1167,18 +1105,13 @@
 // block
 func livenessprologue(lv *Liveness) {
 	var bb *BasicBlock
-	var uevar *Bvec
-	var varkill *Bvec
-	var avarinit *Bvec
 	var p *obj.Prog
-	var i int32
-	var nvars int32
 
-	nvars = int32(len(lv.vars))
-	uevar = bvalloc(nvars)
-	varkill = bvalloc(nvars)
-	avarinit = bvalloc(nvars)
-	for i = 0; i < int32(len(lv.cfg)); i++ {
+	nvars := int32(len(lv.vars))
+	uevar := bvalloc(nvars)
+	varkill := bvalloc(nvars)
+	avarinit := bvalloc(nvars)
+	for i := int32(0); i < int32(len(lv.cfg)); i++ {
 		bb = lv.cfg[i]
 
 		// Walk the block instructions backward and update the block
@@ -1214,29 +1147,20 @@
 // Solve the liveness dataflow equations.
 func livenesssolve(lv *Liveness) {
 	var bb *BasicBlock
-	var succ *BasicBlock
-	var pred *BasicBlock
-	var newlivein *Bvec
-	var newliveout *Bvec
-	var any *Bvec
-	var all *Bvec
 	var rpo int32
-	var i int32
-	var j int32
-	var change int32
 
 	// These temporary bitvectors exist to avoid successive allocations and
 	// frees within the loop.
-	newlivein = bvalloc(int32(len(lv.vars)))
+	newlivein := bvalloc(int32(len(lv.vars)))
 
-	newliveout = bvalloc(int32(len(lv.vars)))
-	any = bvalloc(int32(len(lv.vars)))
-	all = bvalloc(int32(len(lv.vars)))
+	newliveout := bvalloc(int32(len(lv.vars)))
+	any := bvalloc(int32(len(lv.vars)))
+	all := bvalloc(int32(len(lv.vars)))
 
 	// Push avarinitall, avarinitany forward.
 	// avarinitall says the addressed var is initialized along all paths reaching the block exit.
 	// avarinitany says the addressed var is initialized along some path reaching the block exit.
-	for i = 0; i < int32(len(lv.cfg)); i++ {
+	for i := int32(0); i < int32(len(lv.cfg)); i++ {
 		bb = lv.cfg[i]
 		rpo = int32(bb.rpo)
 		if i == 0 {
@@ -1249,7 +1173,10 @@
 		bvcopy(lv.avarinitany[rpo], lv.avarinit[rpo])
 	}
 
-	change = 1
+	change := int32(1)
+	var j int32
+	var i int32
+	var pred *BasicBlock
 	for change != 0 {
 		change = 0
 		for i = 0; i < int32(len(lv.cfg)); i++ {
@@ -1289,6 +1216,7 @@
 	// so low that it hardly seems to be worth the complexity.
 	change = 1
 
+	var succ *BasicBlock
 	for change != 0 {
 		change = 0
 
@@ -1328,19 +1256,17 @@
 // This function is slow but it is only used for generating debug prints.
 // Check whether n is marked live in args/locals.
 func islive(n *Node, args *Bvec, locals *Bvec) bool {
-	var i int
-
 	switch n.Class {
 	case PPARAM,
 		PPARAMOUT:
-		for i = 0; int64(i) < n.Type.Width/int64(Widthptr)*obj.BitsPerPointer; i++ {
+		for i := 0; int64(i) < n.Type.Width/int64(Widthptr)*obj.BitsPerPointer; i++ {
 			if bvget(args, int32(n.Xoffset/int64(Widthptr)*obj.BitsPerPointer+int64(i))) != 0 {
 				return true
 			}
 		}
 
 	case PAUTO:
-		for i = 0; int64(i) < n.Type.Width/int64(Widthptr)*obj.BitsPerPointer; i++ {
+		for i := 0; int64(i) < n.Type.Width/int64(Widthptr)*obj.BitsPerPointer; i++ {
 			if bvget(locals, int32((n.Xoffset+stkptrsize)/int64(Widthptr)*obj.BitsPerPointer+int64(i))) != 0 {
 				return true
 			}
@@ -1355,44 +1281,28 @@
 func livenessepilogue(lv *Liveness) {
 	var bb *BasicBlock
 	var pred *BasicBlock
-	var ambig *Bvec
-	var livein *Bvec
-	var liveout *Bvec
-	var uevar *Bvec
-	var varkill *Bvec
 	var args *Bvec
 	var locals *Bvec
-	var avarinit *Bvec
-	var any *Bvec
-	var all *Bvec
 	var n *Node
 	var p *obj.Prog
-	var next *obj.Prog
-	var i int32
 	var j int32
-	var numlive int32
-	var startmsg int32
-	var nmsg int32
-	var nvars int32
 	var pos int32
 	var xoffset int64
-	var msg []string
-	var fmt_ string
 
-	nvars = int32(len(lv.vars))
-	livein = bvalloc(nvars)
-	liveout = bvalloc(nvars)
-	uevar = bvalloc(nvars)
-	varkill = bvalloc(nvars)
-	avarinit = bvalloc(nvars)
-	any = bvalloc(nvars)
-	all = bvalloc(nvars)
-	ambig = bvalloc(localswords() * obj.BitsPerPointer)
-	msg = nil
-	nmsg = 0
-	startmsg = 0
+	nvars := int32(len(lv.vars))
+	livein := bvalloc(nvars)
+	liveout := bvalloc(nvars)
+	uevar := bvalloc(nvars)
+	varkill := bvalloc(nvars)
+	avarinit := bvalloc(nvars)
+	any := bvalloc(nvars)
+	all := bvalloc(nvars)
+	ambig := bvalloc(localswords() * obj.BitsPerPointer)
+	msg := []string(nil)
+	nmsg := int32(0)
+	startmsg := int32(0)
 
-	for i = 0; i < int32(len(lv.cfg)); i++ {
+	for i := int32(0); i < int32(len(lv.cfg)); i++ {
 		bb = lv.cfg[i]
 
 		// Compute avarinitany and avarinitall for entry to block.
@@ -1481,7 +1391,10 @@
 		bb.lastbitmapindex = len(lv.livepointers) - 1
 	}
 
-	for i = 0; i < int32(len(lv.cfg)); i++ {
+	var fmt_ string
+	var next *obj.Prog
+	var numlive int32
+	for i := int32(0); i < int32(len(lv.cfg)); i++ {
 		bb = lv.cfg[i]
 
 		if debuglive >= 1 && Curfn.Nname.Sym.Name != "init" && Curfn.Nname.Sym.Name[0] != '.' {
@@ -1627,12 +1540,10 @@
 )
 
 func hashbitmap(h uint32, bv *Bvec) uint32 {
-	var i int
-	var n int
 	var w uint32
 
-	n = int((bv.n + 31) / 32)
-	for i = 0; i < n; i++ {
+	n := int((bv.n + 31) / 32)
+	for i := 0; i < n; i++ {
 		w = bv.b[i]
 		h = (h * Hp) ^ (w & 0xff)
 		h = (h * Hp) ^ ((w >> 8) & 0xff)
@@ -1658,45 +1569,37 @@
 // PCDATA tables cost about 100k. So for now we keep using a single index for
 // both bitmap lists.
 func livenesscompact(lv *Liveness) {
-	var table []int
-	var remap []int
-	var i int
-	var j int
-	var n int
-	var tablesize int
-	var uniq int
-	var h uint32
-	var local *Bvec
-	var arg *Bvec
-	var jlocal *Bvec
-	var jarg *Bvec
-	var p *obj.Prog
-
 	// Linear probing hash table of bitmaps seen so far.
 	// The hash table has 4n entries to keep the linear
 	// scan short. An entry of -1 indicates an empty slot.
-	n = len(lv.livepointers)
+	n := len(lv.livepointers)
 
-	tablesize = 4 * n
-	table = make([]int, tablesize)
+	tablesize := 4 * n
+	table := make([]int, tablesize)
 	for i := range table {
 		table[i] = -1
 	}
 
 	// remap[i] = the new index of the old bit vector #i.
-	remap = make([]int, n)
+	remap := make([]int, n)
 
 	for i := range remap {
 		remap[i] = -1
 	}
-	uniq = 0 // unique tables found so far
+	uniq := 0 // unique tables found so far
 
 	// Consider bit vectors in turn.
 	// If new, assign next number using uniq,
 	// record in remap, record in lv->livepointers and lv->argslivepointers
 	// under the new index, and add entry to hash table.
 	// If already seen, record earlier index in remap and free bitmaps.
-	for i = 0; i < n; i++ {
+	var jarg *Bvec
+	var j int
+	var h uint32
+	var arg *Bvec
+	var jlocal *Bvec
+	var local *Bvec
+	for i := 0; i < n; i++ {
 		local = lv.livepointers[i]
 		arg = lv.argslivepointers[i]
 		h = hashbitmap(hashbitmap(H0, local), arg) % uint32(tablesize)
@@ -1732,13 +1635,14 @@
 	// we don't need anymore. Clear the pointers later in the
 	// array so that we can tell where the coalesced bitmaps stop
 	// and so that we don't double-free when cleaning up.
-	for j = uniq; j < n; j++ {
+	for j := uniq; j < n; j++ {
 		lv.livepointers[j] = nil
 		lv.argslivepointers[j] = nil
 	}
 
 	// Rewrite PCDATA instructions to use new numbering.
-	for p = lv.ptxt; p != nil; p = p.Link {
+	var i int
+	for p := lv.ptxt; p != nil; p = p.Link {
 		if p.As == obj.APCDATA && p.From.Offset == obj.PCDATA_StackMapIndex {
 			i = int(p.To.Offset)
 			if i >= 0 {
@@ -1749,12 +1653,10 @@
 }
 
 func printbitset(printed int, name string, vars []*Node, bits *Bvec) int {
-	var i int
-	var started int
 	var n *Node
 
-	started = 0
-	for i = 0; i < len(vars); i++ {
+	started := 0
+	for i := 0; i < len(vars); i++ {
 		if bvget(bits, int32(i)) == 0 {
 			continue
 		}
@@ -1782,27 +1684,22 @@
 // This format synthesizes the information used during the multiple passes
 // into a single presentation.
 func livenessprintdebug(lv *Liveness) {
-	var i int
 	var j int
-	var pcdata int
 	var printed int
 	var bb *BasicBlock
 	var p *obj.Prog
-	var uevar *Bvec
-	var varkill *Bvec
-	var avarinit *Bvec
 	var args *Bvec
 	var locals *Bvec
 	var n *Node
 
 	fmt.Printf("liveness: %s\n", Curfn.Nname.Sym.Name)
 
-	uevar = bvalloc(int32(len(lv.vars)))
-	varkill = bvalloc(int32(len(lv.vars)))
-	avarinit = bvalloc(int32(len(lv.vars)))
+	uevar := bvalloc(int32(len(lv.vars)))
+	varkill := bvalloc(int32(len(lv.vars)))
+	avarinit := bvalloc(int32(len(lv.vars)))
 
-	pcdata = 0
-	for i = 0; i < len(lv.cfg); i++ {
+	pcdata := 0
+	for i := 0; i < len(lv.cfg); i++ {
 		if i > 0 {
 			fmt.Printf("\n")
 		}
@@ -1898,17 +1795,14 @@
 // words that are followed are the raw bitmap words.  The arr argument is an
 // array of Node*s.
 func twobitwritesymbol(arr []*Bvec, sym *Sym) {
-	var bv *Bvec
-	var off int
 	var i int
 	var j int
-	var n int
 	var word uint32
 
-	n = len(arr)
-	off = 0
+	n := len(arr)
+	off := 0
 	off += 4 // number of bitmaps, to fill in later
-	bv = arr[0]
+	bv := arr[0]
 	off = duint32(sym, off, uint32(bv.n)) // number of bits in each bitmap
 	for i = 0; i < n; i++ {
 		// bitmap words
@@ -1944,14 +1838,8 @@
 // the liveness of pointer variables in the function, and emits a runtime data
 // structure read by the garbage collector.
 func liveness(fn *Node, firstp *obj.Prog, argssym *Sym, livesym *Sym) {
-	var cfg []*BasicBlock
-	var vars []*Node
-	var lv *Liveness
-	var debugdelta int
-	var l *NodeList
-
 	// Change name to dump debugging information only for a specific function.
-	debugdelta = 0
+	debugdelta := 0
 
 	if Curfn.Nname.Sym.Name == "!" {
 		debugdelta = 2
@@ -1966,13 +1854,13 @@
 	checkptxt(fn, firstp)
 
 	// Construct the global liveness state.
-	cfg = newcfg(firstp)
+	cfg := newcfg(firstp)
 
 	if debuglive >= 3 {
 		printcfg([]*BasicBlock(cfg))
 	}
-	vars = getvariables(fn)
-	lv = newliveness(fn, firstp, cfg, vars)
+	vars := getvariables(fn)
+	lv := newliveness(fn, firstp, cfg, vars)
 
 	// Run the dataflow framework.
 	livenessprologue(lv)
@@ -2000,7 +1888,7 @@
 	twobitwritesymbol(lv.argslivepointers, argssym)
 
 	// Free everything.
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		if l.N != nil {
 			l.N.Opt = nil
 		}
diff --git a/src/cmd/internal/gc/popt.go b/src/cmd/internal/gc/popt.go
index 8a3601b..756f8eb 100644
--- a/src/cmd/internal/gc/popt.go
+++ b/src/cmd/internal/gc/popt.go
@@ -180,9 +180,6 @@
 var noreturn_symlist [10]*Sym
 
 func Noreturn(p *obj.Prog) bool {
-	var s *Sym
-	var i int
-
 	if noreturn_symlist[0] == nil {
 		noreturn_symlist[0] = Pkglookup("panicindex", Runtimepkg)
 		noreturn_symlist[1] = Pkglookup("panicslice", Runtimepkg)
@@ -197,11 +194,11 @@
 	if p.To.Node == nil {
 		return false
 	}
-	s = ((p.To.Node).(*Node)).Sym
+	s := ((p.To.Node).(*Node)).Sym
 	if s == nil {
 		return false
 	}
-	for i = 0; noreturn_symlist[i] != nil; i++ {
+	for i := 0; noreturn_symlist[i] != nil; i++ {
 		if s == noreturn_symlist[i] {
 			return true
 		}
@@ -219,9 +216,7 @@
 
 /* what instruction does a JMP to p eventually land on? */
 func chasejmp(p *obj.Prog, jmploop *int) *obj.Prog {
-	var n int
-
-	n = 0
+	n := 0
 	for p != nil && p.As == obj.AJMP && p.To.Type == obj.TYPE_BRANCH {
 		n++
 		if n > 10 {
@@ -244,9 +239,7 @@
 
 /* mark all code reachable from firstp as alive */
 func mark(firstp *obj.Prog) {
-	var p *obj.Prog
-
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		if p.Opt != dead {
 			break
 		}
@@ -261,18 +254,14 @@
 }
 
 func fixjmp(firstp *obj.Prog) {
-	var jmploop int
-	var p *obj.Prog
-	var last *obj.Prog
-
 	if Debug['R'] != 0 && Debug['v'] != 0 {
 		fmt.Printf("\nfixjmp\n")
 	}
 
 	// pass 1: resolve jump to jump, mark all code as dead.
-	jmploop = 0
+	jmploop := 0
 
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		if Debug['R'] != 0 && Debug['v'] != 0 {
 			fmt.Printf("%v\n", p)
 		}
@@ -294,9 +283,9 @@
 	mark(firstp)
 
 	// pass 3: delete dead code (mostly JMPs).
-	last = nil
+	last := (*obj.Prog)(nil)
 
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		if p.Opt == dead {
 			if p.Link == nil && p.As == obj.ARET && last != nil && last.As != obj.ARET {
 				// This is the final ARET, and the code so far doesn't have one.
@@ -326,8 +315,8 @@
 	// pass 4: elide JMP to next instruction.
 	// only safe if there are no jumps to JMPs anymore.
 	if jmploop == 0 {
-		last = nil
-		for p = firstp; p != nil; p = p.Link {
+		last := (*obj.Prog)(nil)
+		for p := firstp; p != nil; p = p.Link {
 			if p.As == obj.AJMP && p.To.Type == obj.TYPE_BRANCH && p.To.U.Branch == p.Link {
 				if Debug['R'] != 0 && Debug['v'] != 0 {
 					fmt.Printf("del %v\n", p)
@@ -346,7 +335,7 @@
 
 	if Debug['R'] != 0 && Debug['v'] != 0 {
 		fmt.Printf("\n")
-		for p = firstp; p != nil; p = p.Link {
+		for p := firstp; p != nil; p = p.Link {
 			fmt.Printf("%v\n", p)
 		}
 		fmt.Printf("\n")
@@ -374,20 +363,12 @@
 // If size == 0, f->data will be nil.
 
 func Flowstart(firstp *obj.Prog, newData func() interface{}) *Graph {
-	var id int
-	var nf int
-	var f *Flow
-	var f1 *Flow
-	var start *Flow
-	var last *Flow
-	var graph *Graph
-	var p *obj.Prog
 	var info ProgInfo
 
 	// Count and mark instructions to annotate.
-	nf = 0
+	nf := 0
 
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		p.Opt = nil // should be already, but just in case
 		Thearch.Proginfo(&info, p)
 		if info.Flags&Skip != 0 {
@@ -407,11 +388,12 @@
 	}
 
 	// Allocate annotations and assign to instructions.
-	graph = new(Graph)
+	graph := new(Graph)
 	ff := make([]Flow, nf)
-	start = &ff[0]
-	id = 0
-	for p = firstp; p != nil; p = p.Link {
+	start := &ff[0]
+	id := 0
+	var last *Flow
+	for p := firstp; p != nil; p = p.Link {
 		if p.Opt == nil {
 			continue
 		}
@@ -431,7 +413,9 @@
 	}
 
 	// Fill in pred/succ information.
-	for f = start; f != nil; f = f.Link {
+	var f1 *Flow
+	var p *obj.Prog
+	for f := start; f != nil; f = f.Link {
 		p = f.Prog
 		Thearch.Proginfo(&info, p)
 		if info.Flags&Break == 0 {
@@ -465,9 +449,7 @@
 }
 
 func Flowend(graph *Graph) {
-	var f *Flow
-
-	for f = graph.Start; f != nil; f = f.Link {
+	for f := graph.Start; f != nil; f = f.Link {
 		f.Prog.Opt = nil
 	}
 }
@@ -488,10 +470,8 @@
  *	recursively, all preds with a greater rpo number are in the loop
  */
 func postorder(r *Flow, rpo2r []*Flow, n int32) int32 {
-	var r1 *Flow
-
 	r.Rpo = 1
-	r1 = r.S1
+	r1 := r.S1
 	if r1 != nil && r1.Rpo == 0 {
 		n = postorder(r1, rpo2r, n)
 	}
@@ -505,11 +485,10 @@
 }
 
 func rpolca(idom []int32, rpo1 int32, rpo2 int32) int32 {
-	var t int32
-
 	if rpo1 == -1 {
 		return rpo2
 	}
+	var t int32
 	for rpo1 != rpo2 {
 		if rpo1 > rpo2 {
 			t = rpo2
@@ -537,9 +516,7 @@
 }
 
 func loophead(idom []int32, r *Flow) bool {
-	var src int32
-
-	src = r.Rpo
+	src := r.Rpo
 	if r.P1 != nil && doms(idom, src, r.P1.Rpo) {
 		return true
 	}
@@ -566,40 +543,34 @@
 }
 
 func flowrpo(g *Graph) {
-	var r1 *Flow
-	var i int32
-	var d int32
-	var me int32
-	var nr int32
-	var idom []int32
-	var rpo2r []*Flow
-
 	g.Rpo = make([]*Flow, g.Num)
-	idom = make([]int32, g.Num)
+	idom := make([]int32, g.Num)
 
-	for r1 = g.Start; r1 != nil; r1 = r1.Link {
+	for r1 := g.Start; r1 != nil; r1 = r1.Link {
 		r1.Active = 0
 	}
 
-	rpo2r = g.Rpo
-	d = postorder(g.Start, rpo2r, 0)
-	nr = int32(g.Num)
+	rpo2r := g.Rpo
+	d := postorder(g.Start, rpo2r, 0)
+	nr := int32(g.Num)
 	if d > nr {
 		Fatal("too many reg nodes %d %d", d, nr)
 	}
 	nr = d
-	for i = 0; i < nr/2; i++ {
+	var r1 *Flow
+	for i := int32(0); i < nr/2; i++ {
 		r1 = rpo2r[i]
 		rpo2r[i] = rpo2r[nr-1-i]
 		rpo2r[nr-1-i] = r1
 	}
 
-	for i = 0; i < nr; i++ {
+	for i := int32(0); i < nr; i++ {
 		rpo2r[i].Rpo = i
 	}
 
 	idom[0] = 0
-	for i = 0; i < nr; i++ {
+	var me int32
+	for i := int32(0); i < nr; i++ {
 		r1 = rpo2r[i]
 		me = r1.Rpo
 		d = -1
@@ -617,7 +588,7 @@
 		idom[i] = d
 	}
 
-	for i = 0; i < nr; i++ {
+	for i := int32(0); i < nr; i++ {
 		r1 = rpo2r[i]
 		r1.Loop++
 		if r1.P2 != nil && loophead(idom, r1) {
@@ -625,15 +596,13 @@
 		}
 	}
 
-	for r1 = g.Start; r1 != nil; r1 = r1.Link {
+	for r1 := g.Start; r1 != nil; r1 = r1.Link {
 		r1.Active = 0
 	}
 }
 
 func Uniqp(r *Flow) *Flow {
-	var r1 *Flow
-
-	r1 = r.P1
+	r1 := r.P1
 	if r1 == nil {
 		r1 = r.P2
 		if r1 == nil || r1.P2link != nil {
@@ -646,9 +615,7 @@
 }
 
 func Uniqs(r *Flow) *Flow {
-	var r1 *Flow
-
-	r1 = r.S1
+	r1 := r.S1
 	if r1 == nil {
 		r1 = r.S2
 		if r1 == nil {
@@ -691,11 +658,8 @@
 }
 
 func (x startcmp) Less(i, j int) bool {
-	var a *TempVar
-	var b *TempVar
-
-	a = x[i]
-	b = x[j]
+	a := x[i]
+	b := x[j]
 
 	if a.start < b.start {
 		return true
@@ -723,48 +687,28 @@
 }
 
 func mergetemp(firstp *obj.Prog) {
-	var i int
-	var j int
-	var nvar int
-	var ninuse int
-	var nfree int
-	var nkill int
-	var var_ []TempVar
-	var v *TempVar
-	var v1 *TempVar
-	var bystart []*TempVar
-	var inuse []*TempVar
-	var f *Flow
-	var l *NodeList
-	var lp **NodeList
-	var n *Node
-	var p *obj.Prog
-	var p1 *obj.Prog
-	var t *Type
-	var info ProgInfo
-	var info1 ProgInfo
-	var gen int32
-	var g *Graph
 	const (
 		debugmerge = 1
 	)
 
-	g = Flowstart(firstp, nil)
+	g := Flowstart(firstp, nil)
 	if g == nil {
 		return
 	}
 
 	// Build list of all mergeable variables.
-	nvar = 0
-	for l = Curfn.Dcl; l != nil; l = l.Next {
+	nvar := 0
+	for l := Curfn.Dcl; l != nil; l = l.Next {
 		if canmerge(l.N) {
 			nvar++
 		}
 	}
 
-	var_ = make([]TempVar, nvar)
+	var_ := make([]TempVar, nvar)
 	nvar = 0
-	for l = Curfn.Dcl; l != nil; l = l.Next {
+	var n *Node
+	var v *TempVar
+	for l := Curfn.Dcl; l != nil; l = l.Next {
 		n = l.N
 		if canmerge(n) {
 			v = &var_[nvar]
@@ -778,7 +722,9 @@
 	// We assume that the earliest reference to a temporary is its definition.
 	// This is not true of variables in general but our temporaries are all
 	// single-use (that's why we have so many!).
-	for f = g.Start; f != nil; f = f.Link {
+	var p *obj.Prog
+	var info ProgInfo
+	for f := g.Start; f != nil; f = f.Link {
 		p = f.Prog
 		Thearch.Proginfo(&info, p)
 
@@ -812,10 +758,13 @@
 		Dumpit("before", g.Start, 0)
 	}
 
-	nkill = 0
+	nkill := 0
 
 	// Special case.
-	for i = 0; i < len(var_); i++ {
+	var p1 *obj.Prog
+	var info1 ProgInfo
+	var f *Flow
+	for i := 0; i < len(var_); i++ {
 		v = &var_[i]
 		if v.addr != 0 {
 			continue
@@ -868,9 +817,9 @@
 	// Traverse live range of each variable to set start, end.
 	// Each flood uses a new value of gen so that we don't have
 	// to clear all the r->active words after each variable.
-	gen = 0
+	gen := int32(0)
 
-	for i = 0; i < len(var_); i++ {
+	for i := 0; i < len(var_); i++ {
 		v = &var_[i]
 		gen++
 		for f = v.use; f != nil; f = f.Data.(*Flow) {
@@ -885,9 +834,9 @@
 	}
 
 	// Sort variables by start.
-	bystart = make([]*TempVar, len(var_))
+	bystart := make([]*TempVar, len(var_))
 
-	for i = 0; i < len(var_); i++ {
+	for i := 0; i < len(var_); i++ {
 		bystart[i] = &var_[i]
 	}
 	sort.Sort(startcmp(bystart[:len(var_)]))
@@ -898,11 +847,14 @@
 	// In theory we should use a sorted tree so that insertions are
 	// guaranteed O(log n) and then the loop is guaranteed O(n log n).
 	// In practice, it doesn't really matter.
-	inuse = make([]*TempVar, len(var_))
+	inuse := make([]*TempVar, len(var_))
 
-	ninuse = 0
-	nfree = len(var_)
-	for i = 0; i < len(var_); i++ {
+	ninuse := 0
+	nfree := len(var_)
+	var t *Type
+	var v1 *TempVar
+	var j int
+	for i := 0; i < len(var_); i++ {
 		v = bystart[i]
 		if debugmerge > 0 && Debug['v'] != 0 {
 			fmt.Printf("consider %v: removed=%d\n", Nconv(v.node, obj.FmtSharp), v.removed)
@@ -965,7 +917,8 @@
 
 	if debugmerge > 0 && Debug['v'] != 0 {
 		fmt.Printf("%v [%d - %d]\n", Sconv(Curfn.Nname.Sym, 0), len(var_), nkill)
-		for i = 0; i < len(var_); i++ {
+		var v *TempVar
+		for i := 0; i < len(var_); i++ {
 			v = &var_[i]
 			fmt.Printf("var %v %v %d-%d", Nconv(v.node, obj.FmtSharp), Tconv(v.node.Type, 0), v.start, v.end)
 			if v.addr != 0 {
@@ -989,7 +942,7 @@
 	}
 
 	// Update node references to use merged temporaries.
-	for f = g.Start; f != nil; f = f.Link {
+	for f := g.Start; f != nil; f = f.Link {
 		p = f.Prog
 		n, _ = p.From.Node.(*Node)
 		if n != nil {
@@ -1008,7 +961,8 @@
 	}
 
 	// Delete merged nodes from declaration list.
-	for lp = &Curfn.Dcl; ; {
+	var l *NodeList
+	for lp := &Curfn.Dcl; ; {
 		l = *lp
 		if l == nil {
 			break
@@ -1026,7 +980,7 @@
 	}
 
 	// Clear aux structures.
-	for i = 0; i < len(var_); i++ {
+	for i := 0; i < len(var_); i++ {
 		var_[i].node.Opt = nil
 	}
 
@@ -1036,8 +990,6 @@
 func mergewalk(v *TempVar, f0 *Flow, gen uint32) {
 	var p *obj.Prog
 	var f1 *Flow
-	var f *Flow
-	var f2 *Flow
 
 	for f1 = f0; f1 != nil; f1 = f1.P1 {
 		if uint32(f1.Active) == gen {
@@ -1054,7 +1006,8 @@
 		}
 	}
 
-	for f = f0; f != f1; f = f.P1 {
+	var f2 *Flow
+	for f := f0; f != f1; f = f.P1 {
 		for f2 = f.P2; f2 != nil; f2 = f2.P2link {
 			mergewalk(v, f2, gen)
 		}
@@ -1064,7 +1017,6 @@
 func varkillwalk(v *TempVar, f0 *Flow, gen uint32) {
 	var p *obj.Prog
 	var f1 *Flow
-	var f *Flow
 
 	for f1 = f0; f1 != nil; f1 = f1.S1 {
 		if uint32(f1.Active) == gen {
@@ -1083,7 +1035,7 @@
 		}
 	}
 
-	for f = f0; f != f1; f = f.S1 {
+	for f := f0; f != f1; f = f.S1 {
 		varkillwalk(v, f.S2, gen)
 	}
 }
@@ -1107,13 +1059,7 @@
 var killed int // f->data is either nil or &killed
 
 func nilopt(firstp *obj.Prog) {
-	var f *Flow
-	var p *obj.Prog
-	var g *Graph
-	var ncheck int
-	var nkill int
-
-	g = Flowstart(firstp, nil)
+	g := Flowstart(firstp, nil)
 	if g == nil {
 		return
 	}
@@ -1122,9 +1068,10 @@
 		Dumpit("nilopt", g.Start, 0)
 	}
 
-	ncheck = 0
-	nkill = 0
-	for f = g.Start; f != nil; f = f.Link {
+	ncheck := 0
+	nkill := 0
+	var p *obj.Prog
+	for f := g.Start; f != nil; f = f.Link {
 		p = f.Prog
 		if p.As != obj.ACHECKNIL || !Thearch.Regtyp(&p.From) {
 			continue
@@ -1155,7 +1102,7 @@
 		}
 	}
 
-	for f = g.Start; f != nil; f = f.Link {
+	for f := g.Start; f != nil; f = f.Link {
 		if f.Data != nil {
 			nkill++
 			Thearch.Excise(f)
@@ -1172,9 +1119,8 @@
 func nilwalkback(fcheck *Flow) {
 	var p *obj.Prog
 	var info ProgInfo
-	var f *Flow
 
-	for f = fcheck; f != nil; f = Uniqp(f) {
+	for f := fcheck; f != nil; f = Uniqp(f) {
 		p = f.Prog
 		Thearch.Proginfo(&info, p)
 		if (info.Flags&RightWrite != 0) && Thearch.Sameaddr(&p.To, &fcheck.Prog.From) {
@@ -1231,8 +1177,6 @@
 		nilwalkback(fcheck, f2, gen);
 */
 func nilwalkfwd(fcheck *Flow) {
-	var f *Flow
-	var last *Flow
 	var p *obj.Prog
 	var info ProgInfo
 
@@ -1243,9 +1187,9 @@
 	// avoid problems like:
 	//	_ = *x // should panic
 	//	for {} // no writes but infinite loop may be considered visible
-	last = nil
+	last := (*Flow)(nil)
 
-	for f = Uniqs(fcheck); f != nil; f = Uniqs(f) {
+	for f := Uniqs(fcheck); f != nil; f = Uniqs(f) {
 		p = f.Prog
 		Thearch.Proginfo(&info, p)
 
diff --git a/src/cmd/internal/gc/racewalk.go b/src/cmd/internal/gc/racewalk.go
index 582f6b4..3619fed 100644
--- a/src/cmd/internal/gc/racewalk.go
+++ b/src/cmd/internal/gc/racewalk.go
@@ -31,10 +31,8 @@
 var noinst_pkgs = []string{"sync", "sync/atomic"}
 
 func ispkgin(pkgs []string) bool {
-	var i int
-
 	if myimportpath != "" {
-		for i = 0; i < len(pkgs); i++ {
+		for i := 0; i < len(pkgs); i++ {
 			if myimportpath == pkgs[i] {
 				return true
 			}
@@ -54,10 +52,6 @@
 }
 
 func racewalk(fn *Node) {
-	var nd *Node
-	var nodpc *Node
-	var s string
-
 	if ispkgin(omit_pkgs) || isforkfunc(fn) {
 		return
 	}
@@ -72,18 +66,18 @@
 	// nodpc is the PC of the caller as extracted by
 	// getcallerpc. We use -widthptr(FP) for x86.
 	// BUG: this will not work on arm.
-	nodpc = Nod(OXXX, nil, nil)
+	nodpc := Nod(OXXX, nil, nil)
 
 	*nodpc = *nodfp
 	nodpc.Type = Types[TUINTPTR]
 	nodpc.Xoffset = int64(-Widthptr)
-	nd = mkcall("racefuncenter", nil, nil, nodpc)
+	nd := mkcall("racefuncenter", nil, nil, nodpc)
 	fn.Enter = concat(list1(nd), fn.Enter)
 	nd = mkcall("racefuncexit", nil, nil)
 	fn.Exit = list(fn.Exit, nd)
 
 	if Debug['W'] != 0 {
-		s = fmt.Sprintf("after racewalk %v", Sconv(fn.Nname.Sym, 0))
+		s := fmt.Sprintf("after racewalk %v", Sconv(fn.Nname.Sym, 0))
 		dumplist(s, fn.Nbody)
 		s = fmt.Sprintf("enter %v", Sconv(fn.Nname.Sym, 0))
 		dumplist(s, fn.Enter)
@@ -110,12 +104,7 @@
 // walks the tree and adds calls to the
 // instrumentation code to top-level (statement) nodes' init
 func racewalknode(np **Node, init **NodeList, wr int, skip int) {
-	var n *Node
-	var n1 *Node
-	var l *NodeList
-	var fini *NodeList
-
-	n = *np
+	n := *np
 
 	if n == nil {
 		return
@@ -132,7 +121,7 @@
 		// If init == &n->ninit and n->ninit is non-nil,
 		// racewalknode might append it to itself.
 		// nil it out and handle it separately before putting it back.
-		l = n.Ninit
+		l := n.Ninit
 
 		n.Ninit = nil
 		racewalklist(l, nil)
@@ -174,7 +163,7 @@
 			OCALLINTER:
 			racewalknode(&n.List.N, &n.List.N.Ninit, 0, 0)
 
-			fini = nil
+			fini := (*NodeList)(nil)
 			racewalklist(n.List.Next, &fini)
 			n.List = concat(n.List, fini)
 
@@ -204,6 +193,7 @@
 		if n.Left.Sym != nil && n.Left.Sym.Pkg == Runtimepkg && (strings.HasPrefix(n.Left.Sym.Name, "writebarrier") || n.Left.Sym.Name == "typedmemmove") {
 			// Find the dst argument.
 			// The list can be reordered, so it's not necessary just the first or the second element.
+			var l *NodeList
 			for l = n.List; l != nil; l = l.Next {
 				if n.Left.Sym.Name == "typedmemmove" {
 					if l.N.Left.Xoffset == int64(Widthptr) {
@@ -263,7 +253,7 @@
 		OCAP:
 		racewalknode(&n.Left, init, 0, 0)
 		if Istype(n.Left.Type, TMAP) {
-			n1 = Nod(OCONVNOP, n.Left, nil)
+			n1 := Nod(OCONVNOP, n.Left, nil)
 			n1.Type = Ptrto(Types[TUINT8])
 			n1 = Nod(OIND, n1, nil)
 			typecheck(&n1, Erv)
@@ -495,15 +485,7 @@
 }
 
 func callinstr(np **Node, init **NodeList, wr int, skip int) bool {
-	var name string
-	var f *Node
-	var b *Node
-	var n *Node
-	var t *Type
-	var class int
-	var hascalls int
-
-	n = *np
+	n := *np
 
 	//print("callinstr for %+N [ %O ] etype=%E class=%d\n",
 	//	  n, n->op, n->type ? n->type->etype : -1, n->class);
@@ -511,25 +493,25 @@
 	if skip != 0 || n.Type == nil || n.Type.Etype >= TIDEAL {
 		return false
 	}
-	t = n.Type
+	t := n.Type
 	if isartificial(n) {
 		return false
 	}
 
-	b = outervalue(n)
+	b := outervalue(n)
 
 	// it skips e.g. stores to ... parameter array
 	if isartificial(b) {
 		return false
 	}
-	class = int(b.Class)
+	class := int(b.Class)
 
 	// BUG: we _may_ want to instrument PAUTO sometimes
 	// e.g. if we've got a local variable/method receiver
 	// that has got a pointer inside. Whether it points to
 	// the heap or not is impossible to know at compile time
 	if (class&PHEAP != 0) || class == PPARAMREF || class == PEXTERN || b.Op == OINDEX || b.Op == ODOTPTR || b.Op == OIND {
-		hascalls = 0
+		hascalls := 0
 		foreach(n, hascallspred, &hascalls)
 		if hascalls != 0 {
 			n = detachexpr(n, init)
@@ -538,14 +520,15 @@
 
 		n = treecopy(n)
 		makeaddable(n)
+		var f *Node
 		if t.Etype == TSTRUCT || Isfixedarray(t) {
-			name = "racereadrange"
+			name := "racereadrange"
 			if wr != 0 {
 				name = "racewriterange"
 			}
 			f = mkcall(name, nil, init, uintptraddr(n), Nodintconst(t.Width))
 		} else {
-			name = "raceread"
+			name := "raceread"
 			if wr != 0 {
 				name = "racewrite"
 			}
@@ -592,9 +575,7 @@
 }
 
 func uintptraddr(n *Node) *Node {
-	var r *Node
-
-	r = Nod(OADDR, n, nil)
+	r := Nod(OADDR, n, nil)
 	r.Bounded = true
 	r = conv(r, Types[TUNSAFEPTR])
 	r = conv(r, Types[TUINTPTR])
@@ -602,18 +583,13 @@
 }
 
 func detachexpr(n *Node, init **NodeList) *Node {
-	var addr *Node
-	var as *Node
-	var ind *Node
-	var l *Node
-
-	addr = Nod(OADDR, n, nil)
-	l = temp(Ptrto(n.Type))
-	as = Nod(OAS, l, addr)
+	addr := Nod(OADDR, n, nil)
+	l := temp(Ptrto(n.Type))
+	as := Nod(OAS, l, addr)
 	typecheck(&as, Etop)
 	walkexpr(&as, init)
 	*init = list(*init, as)
-	ind = Nod(OIND, l, nil)
+	ind := Nod(OIND, l, nil)
 	typecheck(&ind, Erv)
 	walkexpr(&ind, init)
 	return ind
@@ -656,13 +632,11 @@
 // appendinit is like addinit in subr.c
 // but appends rather than prepends.
 func appendinit(np **Node, init *NodeList) {
-	var n *Node
-
 	if init == nil {
 		return
 	}
 
-	n = *np
+	n := *np
 	switch n.Op {
 	// There may be multiple refs to this node;
 	// introduce OCONVNOP to hold init list.
diff --git a/src/cmd/internal/gc/range.go b/src/cmd/internal/gc/range.go
index bb30bcf..616c859 100644
--- a/src/cmd/internal/gc/range.go
+++ b/src/cmd/internal/gc/range.go
@@ -12,12 +12,10 @@
 func typecheckrange(n *Node) {
 	var toomany int
 	var why string
-	var t *Type
 	var t1 *Type
 	var t2 *Type
 	var v1 *Node
 	var v2 *Node
-	var ll *NodeList
 
 	// Typechecking order is important here:
 	// 0. first typecheck range expression (slice/map/chan),
@@ -31,13 +29,13 @@
 
 	typecheck(&n.Right, Erv)
 
-	t = n.Right.Type
+	t := n.Right.Type
 	if t == nil {
 		goto out
 	}
 
 	// delicate little dance.  see typecheckas2
-	for ll = n.List; ll != nil; ll = ll.Next {
+	for ll := n.List; ll != nil; ll = ll.Next {
 		if ll.N.Defn != n {
 			typecheck(&ll.N, Erv|Easgn)
 		}
@@ -125,7 +123,7 @@
 out:
 	n.Typecheck = 1
 
-	for ll = n.List; ll != nil; ll = ll.Next {
+	for ll := n.List; ll != nil; ll = ll.Next {
 		if ll.N.Typecheck == 0 {
 			typecheck(&ll.N, Erv|Easgn)
 		}
@@ -137,40 +135,17 @@
 }
 
 func walkrange(n *Node) {
-	var ohv1 *Node
-	var hv1 *Node // hidden (old) val 1, 2 // hidden aggregate, iterator // hidden len, pointer // hidden bool // not hidden aggregate, val 1, 2
-	var hv2 *Node
-	var ha *Node
-	var hit *Node
-	var hn *Node
-	var hp *Node
-	var hb *Node
-	var a *Node
-	var v1 *Node
-	var v2 *Node
-	var fn *Node
-	var tmp *Node
-	var keyname *Node
-	var valname *Node
-	var key *Node
-	var val *Node
-	var body *NodeList
-	var init *NodeList
-	var th *Type
-	var t *Type
-	var lno int
+	t := n.Type
+	init := (*NodeList)(nil)
 
-	t = n.Type
-	init = nil
+	a := n.Right
+	lno := int(setlineno(a))
 
-	a = n.Right
-	lno = int(setlineno(a))
-
-	v1 = nil
+	v1 := (*Node)(nil)
 	if n.List != nil {
 		v1 = n.List.N
 	}
-	v2 = nil
+	v2 := (*Node)(nil)
 	if n.List != nil && n.List.Next != nil && !isblank(n.List.Next.N) {
 		v2 = n.List.Next.N
 	}
@@ -179,8 +154,9 @@
 	// to avoid erroneous processing by racewalk.
 	n.List = nil
 
-	hv2 = nil
+	hv2 := (*Node)(nil)
 
+	var body *NodeList
 	switch t.Etype {
 	default:
 		Fatal("walkrange")
@@ -202,7 +178,7 @@
 						if n.Nbody != nil {
 							if n.Nbody.N != nil { // at least one statement in body
 								if n.Nbody.Next == nil { // at most one statement in body
-									tmp = n.Nbody.N // first statement of body
+									tmp := n.Nbody.N // first statement of body
 									if tmp.Op == OAS {
 										if tmp.Left.Op == OINDEX {
 											if samesafeexpr(tmp.Left.Left, a) {
@@ -223,9 +199,9 @@
 															n.Nincr = nil
 
 															// hp = &a[0]
-															hp = temp(Ptrto(Types[TUINT8]))
+															hp := temp(Ptrto(Types[TUINT8]))
 
-															tmp = Nod(OINDEX, a, Nodintconst(0))
+															tmp := Nod(OINDEX, a, Nodintconst(0))
 															tmp.Bounded = true
 															tmp = Nod(OADDR, tmp, nil)
 															tmp = Nod(OCONVNOP, tmp, nil)
@@ -233,7 +209,7 @@
 															n.Nbody = list(n.Nbody, Nod(OAS, hp, tmp))
 
 															// hn = len(a) * sizeof(elem(a))
-															hn = temp(Types[TUINTPTR])
+															hn := temp(Types[TUINTPTR])
 
 															tmp = Nod(OLEN, a, nil)
 															tmp = Nod(OMUL, tmp, Nodintconst(t.Type.Width))
@@ -241,7 +217,7 @@
 															n.Nbody = list(n.Nbody, Nod(OAS, hn, tmp))
 
 															// memclr(hp, hn)
-															fn = mkcall("memclr", nil, nil, hp, hn)
+															fn := mkcall("memclr", nil, nil, hp, hn)
 
 															n.Nbody = list(n.Nbody, fn)
 
@@ -270,17 +246,17 @@
 		}
 
 		// orderstmt arranged for a copy of the array/slice variable if needed.
-		ha = a
+		ha := a
 
-		hv1 = temp(Types[TINT])
-		hn = temp(Types[TINT])
-		hp = nil
+		hv1 := temp(Types[TINT])
+		hn := temp(Types[TINT])
+		hp := (*Node)(nil)
 
 		init = list(init, Nod(OAS, hv1, nil))
 		init = list(init, Nod(OAS, hn, Nod(OLEN, ha, nil)))
 		if v2 != nil {
 			hp = temp(Ptrto(n.Type.Type))
-			tmp = Nod(OINDEX, ha, Nodintconst(0))
+			tmp := Nod(OINDEX, ha, Nodintconst(0))
 			tmp.Bounded = true
 			init = list(init, Nod(OAS, hp, Nod(OADDR, tmp, nil)))
 		}
@@ -292,7 +268,7 @@
 		} else if v2 == nil {
 			body = list1(Nod(OAS, v1, hv1))
 		} else {
-			a = Nod(OAS2, nil, nil)
+			a := Nod(OAS2, nil, nil)
 			a.List = list(list1(v1), v2)
 			a.Rlist = list(list1(hv1), Nod(OIND, hp, nil))
 			body = list1(a)
@@ -305,7 +281,7 @@
 			// Advancing during the increment ensures that the pointer p only points
 			// pass the end of the array during the final "p++; i++; if(i >= len(x)) break;",
 			// after which p is dead, so it cannot confuse the collector.
-			tmp = Nod(OADD, hp, Nodintconst(t.Type.Width))
+			tmp := Nod(OADD, hp, Nodintconst(t.Type.Width))
 
 			tmp.Type = hp.Type
 			tmp.Typecheck = 1
@@ -319,16 +295,16 @@
 		// orderstmt allocated the iterator for us.
 	// we only use a once, so no copy needed.
 	case TMAP:
-		ha = a
+		ha := a
 
-		th = hiter(t)
-		hit = n.Alloc
+		th := hiter(t)
+		hit := n.Alloc
 		hit.Type = th
 		n.Left = nil
-		keyname = newname(th.Type.Sym)      // depends on layout of iterator struct.  See reflect.c:hiter
-		valname = newname(th.Type.Down.Sym) // ditto
+		keyname := newname(th.Type.Sym)      // depends on layout of iterator struct.  See reflect.c:hiter
+		valname := newname(th.Type.Down.Sym) // ditto
 
-		fn = syslook("mapiterinit", 1)
+		fn := syslook("mapiterinit", 1)
 
 		argtype(fn, t.Down)
 		argtype(fn, t.Type)
@@ -340,16 +316,16 @@
 		argtype(fn, th)
 		n.Nincr = mkcall1(fn, nil, nil, Nod(OADDR, hit, nil))
 
-		key = Nod(ODOT, hit, keyname)
+		key := Nod(ODOT, hit, keyname)
 		key = Nod(OIND, key, nil)
 		if v1 == nil {
 			body = nil
 		} else if v2 == nil {
 			body = list1(Nod(OAS, v1, key))
 		} else {
-			val = Nod(ODOT, hit, valname)
+			val := Nod(ODOT, hit, valname)
 			val = Nod(OIND, val, nil)
-			a = Nod(OAS2, nil, nil)
+			a := Nod(OAS2, nil, nil)
 			a.List = list(list1(v1), v2)
 			a.Rlist = list(list1(key), val)
 			body = list1(a)
@@ -357,19 +333,19 @@
 
 		// orderstmt arranged for a copy of the channel variable.
 	case TCHAN:
-		ha = a
+		ha := a
 
 		n.Ntest = nil
 
-		hv1 = temp(t.Type)
+		hv1 := temp(t.Type)
 		hv1.Typecheck = 1
 		if haspointers(t.Type) {
 			init = list(init, Nod(OAS, hv1, nil))
 		}
-		hb = temp(Types[TBOOL])
+		hb := temp(Types[TBOOL])
 
 		n.Ntest = Nod(ONE, hb, Nodbool(false))
-		a = Nod(OAS2RECV, nil, nil)
+		a := Nod(OAS2RECV, nil, nil)
 		a.Typecheck = 1
 		a.List = list(list1(hv1), hb)
 		a.Rlist = list1(Nod(ORECV, ha, nil))
@@ -382,20 +358,21 @@
 
 		// orderstmt arranged for a copy of the string variable.
 	case TSTRING:
-		ha = a
+		ha := a
 
-		ohv1 = temp(Types[TINT])
+		ohv1 := temp(Types[TINT])
 
-		hv1 = temp(Types[TINT])
+		hv1 := temp(Types[TINT])
 		init = list(init, Nod(OAS, hv1, nil))
 
+		var a *Node
 		if v2 == nil {
 			a = Nod(OAS, hv1, mkcall("stringiter", Types[TINT], nil, ha, hv1))
 		} else {
 			hv2 = temp(runetype)
 			a = Nod(OAS2, nil, nil)
 			a.List = list(list1(hv1), hv2)
-			fn = syslook("stringiter2", 0)
+			fn := syslook("stringiter2", 0)
 			a.Rlist = list1(mkcall1(fn, getoutargx(fn.Type), nil, ha, hv1))
 		}
 
diff --git a/src/cmd/internal/gc/reflect.go b/src/cmd/internal/gc/reflect.go
index ee08040..6059e35 100644
--- a/src/cmd/internal/gc/reflect.go
+++ b/src/cmd/internal/gc/reflect.go
@@ -15,9 +15,7 @@
 var signatlist *NodeList
 
 func sigcmp(a *Sig, b *Sig) int {
-	var i int
-
-	i = stringsCompare(a.name, b.name)
+	i := stringsCompare(a.name, b.name)
 	if i != 0 {
 		return i
 	}
@@ -34,16 +32,12 @@
 }
 
 func lsort(l *Sig, f func(*Sig, *Sig) int) *Sig {
-	var l1 *Sig
-	var l2 *Sig
-	var le *Sig
-
 	if l == nil || l.link == nil {
 		return l
 	}
 
-	l1 = l
-	l2 = l
+	l1 := l
+	l2 := l
 	for {
 		l2 = l2.link
 		if l2 == nil {
@@ -70,7 +64,7 @@
 		l2 = l2.link
 	}
 
-	le = l
+	le := l
 
 	for {
 		if l1 == nil {
@@ -121,9 +115,7 @@
 )
 
 func makefield(name string, t *Type) *Type {
-	var f *Type
-
-	f = typ(TFIELD)
+	f := typ(TFIELD)
 	f.Type = t
 	f.Sym = new(Sym)
 	f.Sym.Name = name
@@ -131,20 +123,13 @@
 }
 
 func mapbucket(t *Type) *Type {
-	var keytype *Type
-	var valtype *Type
-	var bucket *Type
-	var arr *Type
-	var field [4]*Type
-	var n int32
-
 	if t.Bucket != nil {
 		return t.Bucket
 	}
 
-	bucket = typ(TSTRUCT)
-	keytype = t.Down
-	valtype = t.Type
+	bucket := typ(TSTRUCT)
+	keytype := t.Down
+	valtype := t.Type
 	dowidth(keytype)
 	dowidth(valtype)
 	if keytype.Width > MAXKEYSIZE {
@@ -155,10 +140,11 @@
 	}
 
 	// The first field is: uint8 topbits[BUCKETSIZE].
-	arr = typ(TARRAY)
+	arr := typ(TARRAY)
 
 	arr.Type = Types[TUINT8]
 	arr.Bound = BUCKETSIZE
+	var field [4]*Type
 	field[0] = makefield("topbits", arr)
 	arr = typ(TARRAY)
 	arr.Type = keytype
@@ -175,7 +161,7 @@
 
 	bucket.Local = t.Local
 	bucket.Type = field[0]
-	for n = 0; n < int32(len(field)-1); n++ {
+	for n := int32(0); n < int32(len(field)-1); n++ {
 		field[n].Down = field[n+1]
 	}
 	field[len(field)-1].Down = nil
@@ -201,16 +187,12 @@
 // Builds a type representing a Hmap structure for the given map type.
 // Make sure this stays in sync with ../../runtime/hashmap.go!
 func hmap(t *Type) *Type {
-	var h *Type
-	var bucket *Type
-	var field [8]*Type
-	var n int32
-
 	if t.Hmap != nil {
 		return t.Hmap
 	}
 
-	bucket = mapbucket(t)
+	bucket := mapbucket(t)
+	var field [8]*Type
 	field[0] = makefield("count", Types[TINT])
 	field[1] = makefield("flags", Types[TUINT8])
 	field[2] = makefield("B", Types[TUINT8])
@@ -220,11 +202,11 @@
 	field[6] = makefield("nevacuate", Types[TUINTPTR])
 	field[7] = makefield("overflow", Types[TUNSAFEPTR])
 
-	h = typ(TSTRUCT)
+	h := typ(TSTRUCT)
 	h.Noalg = 1
 	h.Local = t.Local
 	h.Type = field[0]
-	for n = 0; n < int32(len(field)-1); n++ {
+	for n := int32(0); n < int32(len(field)-1); n++ {
 		field[n].Down = field[n+1]
 	}
 	field[len(field)-1].Down = nil
@@ -235,10 +217,6 @@
 }
 
 func hiter(t *Type) *Type {
-	var n int32
-	var field [12]*Type
-	var i *Type
-
 	if t.Hiter != nil {
 		return t.Hiter
 	}
@@ -259,6 +237,7 @@
 	//    checkBucket uintptr
 	// }
 	// must match ../../runtime/hashmap.c:hash_iter.
+	var field [12]*Type
 	field[0] = makefield("key", Ptrto(t.Down))
 
 	field[1] = makefield("val", Ptrto(t.Type))
@@ -274,11 +253,11 @@
 	field[11] = makefield("checkBucket", Types[TUINTPTR])
 
 	// build iterator struct holding the above fields
-	i = typ(TSTRUCT)
+	i := typ(TSTRUCT)
 
 	i.Noalg = 1
 	i.Type = field[0]
-	for n = 0; n < int32(len(field)-1); n++ {
+	for n := int32(0); n < int32(len(field)-1); n++ {
 		field[n].Down = field[n+1]
 	}
 	field[len(field)-1].Down = nil
@@ -296,33 +275,29 @@
  * return function type, receiver as first argument (or not).
  */
 func methodfunc(f *Type, receiver *Type) *Type {
-	var in *NodeList
-	var out *NodeList
-	var d *Node
-	var t *Type
-
-	in = nil
+	in := (*NodeList)(nil)
 	if receiver != nil {
-		d = Nod(ODCLFIELD, nil, nil)
+		d := Nod(ODCLFIELD, nil, nil)
 		d.Type = receiver
 		in = list(in, d)
 	}
 
-	for t = getinargx(f).Type; t != nil; t = t.Down {
+	var d *Node
+	for t := getinargx(f).Type; t != nil; t = t.Down {
 		d = Nod(ODCLFIELD, nil, nil)
 		d.Type = t.Type
 		d.Isddd = t.Isddd
 		in = list(in, d)
 	}
 
-	out = nil
-	for t = getoutargx(f).Type; t != nil; t = t.Down {
+	out := (*NodeList)(nil)
+	for t := getoutargx(f).Type; t != nil; t = t.Down {
 		d = Nod(ODCLFIELD, nil, nil)
 		d.Type = t.Type
 		out = list(out, d)
 	}
 
-	t = functype(nil, in, out)
+	t := functype(nil, in, out)
 	if f.Nname != nil {
 		// Link to name of original method function.
 		t.Nname = f.Nname
@@ -336,16 +311,8 @@
  * generates stub functions as needed.
  */
 func methods(t *Type) *Sig {
-	var f *Type
-	var mt *Type
-	var it *Type
-	var this *Type
-	var a *Sig
-	var b *Sig
-	var method *Sym
-
 	// method type
-	mt = methtype(t, 0)
+	mt := methtype(t, 0)
 
 	if mt == nil {
 		return nil
@@ -353,7 +320,7 @@
 	expandmeth(mt)
 
 	// type stored in interface word
-	it = t
+	it := t
 
 	if !isdirectiface(it) {
 		it = Ptrto(t)
@@ -361,9 +328,12 @@
 
 	// make list of methods for t,
 	// generating code if necessary.
-	a = nil
+	a := (*Sig)(nil)
 
-	for f = mt.Xmethod; f != nil; f = f.Down {
+	var this *Type
+	var b *Sig
+	var method *Sym
+	for f := mt.Xmethod; f != nil; f = f.Down {
 		if f.Etype != TFIELD {
 			Fatal("methods: not field %v", Tconv(f, 0))
 		}
@@ -439,15 +409,12 @@
  */
 func imethods(t *Type) *Sig {
 	var a *Sig
-	var all *Sig
-	var last *Sig
-	var f *Type
 	var method *Sym
 	var isym *Sym
 
-	all = nil
-	last = nil
-	for f = t.Type; f != nil; f = f.Down {
+	all := (*Sig)(nil)
+	last := (*Sig)(nil)
+	for f := t.Type; f != nil; f = f.Down {
 		if f.Etype != TFIELD {
 			Fatal("imethods: not field")
 		}
@@ -501,9 +468,6 @@
 var dimportpath_gopkg *Pkg
 
 func dimportpath(p *Pkg) {
-	var nam string
-	var n *Node
-
 	if p.Pathsym != nil {
 		return
 	}
@@ -513,9 +477,9 @@
 		dimportpath_gopkg.Name = "go"
 	}
 
-	nam = fmt.Sprintf("importpath.%s.", p.Prefix)
+	nam := fmt.Sprintf("importpath.%s.", p.Prefix)
 
-	n = Nod(ONAME, nil, nil)
+	n := Nod(ONAME, nil, nil)
 	n.Sym = Pkglookup(nam, dimportpath_gopkg)
 
 	n.Class = PEXTERN
@@ -552,13 +516,7 @@
  * ../../runtime/type.go:/uncommonType
  */
 func dextratype(sym *Sym, off int, t *Type, ptroff int) int {
-	var ot int
-	var n int
-	var s *Sym
-	var a *Sig
-	var m *Sig
-
-	m = methods(t)
+	m := methods(t)
 	if t.Sym == nil && m == nil {
 		return off
 	}
@@ -568,14 +526,14 @@
 
 	dsymptr(sym, ptroff, sym, off)
 
-	n = 0
-	for a = m; a != nil; a = a.link {
+	n := 0
+	for a := m; a != nil; a = a.link {
 		dtypesym(a.type_)
 		n++
 	}
 
-	ot = off
-	s = sym
+	ot := off
+	s := sym
 	if t.Sym != nil {
 		ot = dgostringptr(s, ot, t.Sym.Name)
 		if t != Types[t.Etype] && t != errortype {
@@ -595,7 +553,7 @@
 	ot = duintxx(s, ot, uint64(n), Widthint)
 
 	// methods
-	for a = m; a != nil; a = a.link {
+	for a := m; a != nil; a = a.link {
 		// method
 		// ../../runtime/type.go:/method
 		ot = dgostringptr(s, ot, a.name)
@@ -648,13 +606,11 @@
 }
 
 func haspointers(t *Type) bool {
-	var t1 *Type
-	var ret bool
-
 	if t.Haspointers != 0 {
 		return t.Haspointers-1 != 0
 	}
 
+	var ret bool
 	switch t.Etype {
 	case TINT,
 		TUINT,
@@ -689,7 +645,7 @@
 
 	case TSTRUCT:
 		ret = false
-		for t1 = t.Type; t1 != nil; t1 = t1.Down {
+		for t1 := t.Type; t1 != nil; t1 = t1.Down {
 			if haspointers(t1.Type) {
 				ret = true
 				break
@@ -721,36 +677,22 @@
 var dcommontype_algarray *Sym
 
 func dcommontype(s *Sym, ot int, t *Type) int {
-	var i int
-	var alg int
-	var sizeofAlg int
-	var gcprog bool
-	var sptr *Sym
-	var algsym *Sym
-	var zero *Sym
-	var gcprog0 *Sym
-	var gcprog1 *Sym
-	var sbits *Sym
-	var gcmask [16]uint8
-	var x1 uint64
-	var x2 uint64
-	var p string
-
 	if ot != 0 {
 		Fatal("dcommontype %d", ot)
 	}
 
-	sizeofAlg = 2 * Widthptr
+	sizeofAlg := 2 * Widthptr
 	if dcommontype_algarray == nil {
 		dcommontype_algarray = Pkglookup("algarray", Runtimepkg)
 	}
 	dowidth(t)
-	alg = algtype(t)
-	algsym = nil
+	alg := algtype(t)
+	algsym := (*Sym)(nil)
 	if alg < 0 || alg == AMEM {
 		algsym = dalgsym(t)
 	}
 
+	var sptr *Sym
 	if t.Sym != nil && Isptr[t.Etype] == 0 {
 		sptr = dtypesym(Ptrto(t))
 	} else {
@@ -762,7 +704,7 @@
 	// might be returned by a runtime call (map access return value,
 	// 2-arg type cast) declares the size of the zerovalue it needs.
 	// The linker magically takes the max of all the sizes.
-	zero = Pkglookup("zerovalue", Runtimepkg)
+	zero := Pkglookup("zerovalue", Runtimepkg)
 
 	// We use size 0 here so we get the pointer to the zero value,
 	// but don't allocate space for the zero value unless we need it.
@@ -791,7 +733,7 @@
 	ot = duint8(s, ot, 0) // unused
 
 	// runtime (and common sense) expects alignment to be a power of two.
-	i = int(t.Align)
+	i := int(t.Align)
 
 	if i == 0 {
 		i = 1
@@ -802,7 +744,7 @@
 	ot = duint8(s, ot, t.Align) // align
 	ot = duint8(s, ot, t.Align) // fieldAlign
 
-	gcprog = usegcprog(t)
+	gcprog := usegcprog(t)
 
 	i = kinds[t.Etype]
 	if t.Etype == TARRAY && t.Bound < 0 {
@@ -826,6 +768,8 @@
 
 	// gc
 	if gcprog {
+		var gcprog1 *Sym
+		var gcprog0 *Sym
 		gengcprog(t, &gcprog0, &gcprog1)
 		if gcprog0 != nil {
 			ot = dsymptr(s, ot, gcprog0, 0)
@@ -834,25 +778,27 @@
 		}
 		ot = dsymptr(s, ot, gcprog1, 0)
 	} else {
+		var gcmask [16]uint8
 		gengcmask(t, gcmask[:])
-		x1 = 0
-		for i = 0; i < 8; i++ {
+		x1 := uint64(0)
+		for i := 0; i < 8; i++ {
 			x1 = x1<<8 | uint64(gcmask[i])
 		}
+		var p string
 		if Widthptr == 4 {
 			p = fmt.Sprintf("gcbits.0x%016x", x1)
 		} else {
-			x2 = 0
-			for i = 0; i < 8; i++ {
+			x2 := uint64(0)
+			for i := 0; i < 8; i++ {
 				x2 = x2<<8 | uint64(gcmask[i+8])
 			}
 			p = fmt.Sprintf("gcbits.0x%016x%016x", x1, x2)
 		}
 
-		sbits = Pkglookup(p, Runtimepkg)
+		sbits := Pkglookup(p, Runtimepkg)
 		if sbits.Flags&SymUniq == 0 {
 			sbits.Flags |= SymUniq
-			for i = 0; i < 2*Widthptr; i++ {
+			for i := 0; i < 2*Widthptr; i++ {
 				duint8(sbits, i, gcmask[i])
 			}
 			ggloblsym(sbits, 2*int32(Widthptr), obj.DUPOK|obj.RODATA)
@@ -862,7 +808,7 @@
 		ot = duintptr(s, ot, 0)
 	}
 
-	p = fmt.Sprintf("%v", Tconv(t, obj.FmtLeft|obj.FmtUnsigned))
+	p := fmt.Sprintf("%v", Tconv(t, obj.FmtLeft|obj.FmtUnsigned))
 
 	//print("dcommontype: %s\n", p);
 	ot = dgostringptr(s, ot, p) // string
@@ -879,11 +825,8 @@
 }
 
 func typesym(t *Type) *Sym {
-	var p string
-	var s *Sym
-
-	p = fmt.Sprintf("%v", Tconv(t, obj.FmtLeft))
-	s = Pkglookup(p, typepkg)
+	p := fmt.Sprintf("%v", Tconv(t, obj.FmtLeft))
+	s := Pkglookup(p, typepkg)
 
 	//print("typesym: %s -> %+S\n", p, s);
 
@@ -891,19 +834,13 @@
 }
 
 func tracksym(t *Type) *Sym {
-	var p string
-	var s *Sym
-
-	p = fmt.Sprintf("%v.%s", Tconv(t.Outer, obj.FmtLeft), t.Sym.Name)
-	s = Pkglookup(p, trackpkg)
+	p := fmt.Sprintf("%v.%s", Tconv(t.Outer, obj.FmtLeft), t.Sym.Name)
+	s := Pkglookup(p, trackpkg)
 
 	return s
 }
 
 func typelinksym(t *Type) *Sym {
-	var p string
-	var s *Sym
-
 	// %-uT is what the generated Type's string field says.
 	// It uses (ambiguous) package names instead of import paths.
 	// %-T is the complete, unambiguous type name.
@@ -912,9 +849,9 @@
 	// disambiguate. The names are a little long but they are
 	// discarded by the linker and do not end up in the symbol
 	// table of the final binary.
-	p = fmt.Sprintf("%v/%v", Tconv(t, obj.FmtLeft|obj.FmtUnsigned), Tconv(t, obj.FmtLeft))
+	p := fmt.Sprintf("%v/%v", Tconv(t, obj.FmtLeft|obj.FmtUnsigned), Tconv(t, obj.FmtLeft))
 
-	s = Pkglookup(p, typelinkpkg)
+	s := Pkglookup(p, typelinkpkg)
 
 	//print("typelinksym: %s -> %+S\n", p, s);
 
@@ -922,11 +859,8 @@
 }
 
 func typesymprefix(prefix string, t *Type) *Sym {
-	var p string
-	var s *Sym
-
-	p = fmt.Sprintf("%s.%v", prefix, Tconv(t, obj.FmtLeft))
-	s = Pkglookup(p, typepkg)
+	p := fmt.Sprintf("%s.%v", prefix, Tconv(t, obj.FmtLeft))
+	s := Pkglookup(p, typepkg)
 
 	//print("algsym: %s -> %+S\n", p, s);
 
@@ -934,15 +868,12 @@
 }
 
 func typenamesym(t *Type) *Sym {
-	var s *Sym
-	var n *Node
-
 	if t == nil || (Isptr[t.Etype] != 0 && t.Type == nil) || isideal(t) {
 		Fatal("typename %v", Tconv(t, 0))
 	}
-	s = typesym(t)
+	s := typesym(t)
 	if s.Def == nil {
-		n = Nod(ONAME, nil, nil)
+		n := Nod(ONAME, nil, nil)
 		n.Sym = s
 		n.Type = Types[TUINT8]
 		n.Addable = 1
@@ -959,11 +890,8 @@
 }
 
 func typename(t *Type) *Node {
-	var s *Sym
-	var n *Node
-
-	s = typenamesym(t)
-	n = Nod(OADDR, s.Def, nil)
+	s := typenamesym(t)
+	n := Nod(OADDR, s.Def, nil)
 	n.Type = Ptrto(s.Def.Type)
 	n.Addable = 1
 	n.Ullman = 2
@@ -972,11 +900,8 @@
 }
 
 func weaktypesym(t *Type) *Sym {
-	var p string
-	var s *Sym
-
-	p = fmt.Sprintf("%v", Tconv(t, obj.FmtLeft))
-	s = Pkglookup(p, weaktypepkg)
+	p := fmt.Sprintf("%v", Tconv(t, obj.FmtLeft))
+	s := Pkglookup(p, weaktypepkg)
 
 	//print("weaktypesym: %s -> %+S\n", p, s);
 
@@ -988,7 +913,6 @@
  * That is, if x==x for all x of type t.
  */
 func isreflexive(t *Type) bool {
-	var t1 *Type
 	switch t.Etype {
 	case TBOOL,
 		TINT,
@@ -1023,7 +947,7 @@
 		return isreflexive(t.Type)
 
 	case TSTRUCT:
-		for t1 = t.Type; t1 != nil; t1 = t1.Down {
+		for t1 := t.Type; t1 != nil; t1 = t1.Down {
 			if !isreflexive(t1.Type) {
 				return false
 			}
@@ -1038,22 +962,8 @@
 }
 
 func dtypesym(t *Type) *Sym {
-	var ot int
-	var xt int
 	var n int
-	var isddd int
-	var dupok int
-	var s *Sym
-	var s1 *Sym
-	var s2 *Sym
-	var s3 *Sym
-	var s4 *Sym
-	var slink *Sym
-	var a *Sig
-	var m *Sig
 	var t1 *Type
-	var tbase *Type
-	var t2 *Type
 
 	// Replace byte, rune aliases with real type.
 	// They've been separate internally to make error messages
@@ -1066,7 +976,7 @@
 		Fatal("dtypesym %v", Tconv(t, 0))
 	}
 
-	s = typesym(t)
+	s := typesym(t)
 	if s.Flags&SymSiggen != 0 {
 		return s
 	}
@@ -1075,12 +985,12 @@
 	// special case (look for runtime below):
 	// when compiling package runtime,
 	// emit the type structures for int, float, etc.
-	tbase = t
+	tbase := t
 
 	if Isptr[t.Etype] != 0 && t.Sym == nil && t.Type.Sym != nil {
 		tbase = t.Type
 	}
-	dupok = 0
+	dupok := 0
 	if tbase.Sym == nil {
 		dupok = obj.DUPOK
 	}
@@ -1098,8 +1008,8 @@
 	}
 
 ok:
-	ot = 0
-	xt = 0
+	ot := 0
+	xt := 0
 	switch t.Etype {
 	default:
 		ot = dcommontype(s, ot, t)
@@ -1108,12 +1018,12 @@
 	case TARRAY:
 		if t.Bound >= 0 {
 			// ../../runtime/type.go:/ArrayType
-			s1 = dtypesym(t.Type)
+			s1 := dtypesym(t.Type)
 
-			t2 = typ(TARRAY)
+			t2 := typ(TARRAY)
 			t2.Type = t.Type
 			t2.Bound = -1 // slice
-			s2 = dtypesym(t2)
+			s2 := dtypesym(t2)
 			ot = dcommontype(s, ot, t)
 			xt = ot - 3*Widthptr
 			ot = dsymptr(s, ot, s1, 0)
@@ -1121,7 +1031,7 @@
 			ot = duintptr(s, ot, uint64(t.Bound))
 		} else {
 			// ../../runtime/type.go:/SliceType
-			s1 = dtypesym(t.Type)
+			s1 := dtypesym(t.Type)
 
 			ot = dcommontype(s, ot, t)
 			xt = ot - 3*Widthptr
@@ -1130,7 +1040,7 @@
 
 		// ../../runtime/type.go:/ChanType
 	case TCHAN:
-		s1 = dtypesym(t.Type)
+		s1 := dtypesym(t.Type)
 
 		ot = dcommontype(s, ot, t)
 		xt = ot - 3*Widthptr
@@ -1141,7 +1051,7 @@
 		for t1 = getthisx(t).Type; t1 != nil; t1 = t1.Down {
 			dtypesym(t1.Type)
 		}
-		isddd = 0
+		isddd := 0
 		for t1 = getinargx(t).Type; t1 != nil; t1 = t1.Down {
 			isddd = int(t1.Isddd)
 			dtypesym(t1.Type)
@@ -1178,9 +1088,9 @@
 		}
 
 	case TINTER:
-		m = imethods(t)
+		m := imethods(t)
 		n = 0
-		for a = m; a != nil; a = a.link {
+		for a := m; a != nil; a = a.link {
 			dtypesym(a.type_)
 			n++
 		}
@@ -1192,7 +1102,7 @@
 		ot = dsymptr(s, ot, s, ot+Widthptr+2*Widthint)
 		ot = duintxx(s, ot, uint64(n), Widthint)
 		ot = duintxx(s, ot, uint64(n), Widthint)
-		for a = m; a != nil; a = a.link {
+		for a := m; a != nil; a = a.link {
 			// ../../runtime/type.go:/imethod
 			ot = dgostringptr(s, ot, a.name)
 
@@ -1202,11 +1112,11 @@
 
 		// ../../runtime/type.go:/MapType
 	case TMAP:
-		s1 = dtypesym(t.Down)
+		s1 := dtypesym(t.Down)
 
-		s2 = dtypesym(t.Type)
-		s3 = dtypesym(mapbucket(t))
-		s4 = dtypesym(hmap(t))
+		s2 := dtypesym(t.Type)
+		s3 := dtypesym(mapbucket(t))
+		s4 := dtypesym(hmap(t))
 		ot = dcommontype(s, ot, t)
 		xt = ot - 3*Widthptr
 		ot = dsymptr(s, ot, s1, 0)
@@ -1242,7 +1152,7 @@
 		}
 
 		// ../../runtime/type.go:/PtrType
-		s1 = dtypesym(t.Type)
+		s1 := dtypesym(t.Type)
 
 		ot = dcommontype(s, ot, t)
 		xt = ot - 3*Widthptr
@@ -1300,7 +1210,7 @@
 		case TARRAY,
 			TCHAN,
 			TMAP:
-			slink = typelinksym(t)
+			slink := typelinksym(t)
 			dsymptr(slink, 0, s, 0)
 			ggloblsym(slink, int32(Widthptr), int8(dupok|obj.RODATA))
 		}
@@ -1310,14 +1220,10 @@
 }
 
 func dumptypestructs() {
-	var i int
-	var l *NodeList
 	var n *Node
-	var t *Type
-	var p *Pkg
 
 	// copy types from externdcl list to signatlist
-	for l = externdcl; l != nil; l = l.Next {
+	for l := externdcl; l != nil; l = l.Next {
 		n = l.N
 		if n.Op != OTYPE {
 			continue
@@ -1326,7 +1232,8 @@
 	}
 
 	// process signatlist
-	for l = signatlist; l != nil; l = l.Next {
+	var t *Type
+	for l := signatlist; l != nil; l = l.Next {
 		n = l.N
 		if n.Op != OTYPE {
 			continue
@@ -1339,7 +1246,8 @@
 	}
 
 	// generate import strings for imported packages
-	for i = 0; i < len(phash); i++ {
+	var p *Pkg
+	for i := 0; i < len(phash); i++ {
 		for p = phash[i]; p != nil; p = p.Link {
 			if p.Direct != 0 {
 				dimportpath(p)
@@ -1354,7 +1262,7 @@
 	// another possible choice would be package main,
 	// but using runtime means fewer copies in .6 files.
 	if compiling_runtime != 0 {
-		for i = 1; i <= TBOOL; i++ {
+		for i := 1; i <= TBOOL; i++ {
 			dtypesym(Ptrto(Types[i]))
 		}
 		dtypesym(Ptrto(Types[TSTRING]))
@@ -1377,20 +1285,16 @@
 }
 
 func dalgsym(t *Type) *Sym {
-	var ot int
 	var s *Sym
-	var hash *Sym
 	var hashfunc *Sym
-	var eq *Sym
 	var eqfunc *Sym
-	var p string
 
 	// dalgsym is only called for a type that needs an algorithm table,
 	// which implies that the type is comparable (or else it would use ANOEQ).
 
 	if algtype(t) == AMEM {
 		// we use one algorithm table for all AMEM types of a given size
-		p = fmt.Sprintf(".alg%d", t.Width)
+		p := fmt.Sprintf(".alg%d", t.Width)
 
 		s = Pkglookup(p, typepkg)
 
@@ -1404,7 +1308,7 @@
 
 		hashfunc = Pkglookup(p, typepkg)
 
-		ot = 0
+		ot := 0
 		ot = dsymptr(hashfunc, ot, Pkglookup("memhash_varlen", Runtimepkg), 0)
 		ot = duintxx(hashfunc, ot, uint64(t.Width), Widthptr) // size encoded in closure
 		ggloblsym(hashfunc, int32(ot), obj.DUPOK|obj.RODATA)
@@ -1422,8 +1326,8 @@
 		// generate an alg table specific to this type
 		s = typesymprefix(".alg", t)
 
-		hash = typesymprefix(".hash", t)
-		eq = typesymprefix(".eq", t)
+		hash := typesymprefix(".hash", t)
+		eq := typesymprefix(".eq", t)
 		hashfunc = typesymprefix(".hashfunc", t)
 		eqfunc = typesymprefix(".eqfunc", t)
 
@@ -1439,7 +1343,7 @@
 	}
 
 	// ../../runtime/alg.go:/typeAlg
-	ot = 0
+	ot := 0
 
 	ot = dsymptr(s, ot, hashfunc, 0)
 	ot = dsymptr(s, ot, eqfunc, 0)
@@ -1448,9 +1352,6 @@
 }
 
 func usegcprog(t *Type) bool {
-	var size int64
-	var nptr int64
-
 	if !haspointers(t) {
 		return false
 	}
@@ -1459,9 +1360,9 @@
 	}
 
 	// Calculate size of the unrolled GC mask.
-	nptr = (t.Width + int64(Widthptr) - 1) / int64(Widthptr)
+	nptr := (t.Width + int64(Widthptr) - 1) / int64(Widthptr)
 
-	size = nptr
+	size := nptr
 	if size%2 != 0 {
 		size *= 2 // repeated
 	}
@@ -1478,16 +1379,7 @@
 
 // Generates sparse GC bitmask (4 bits per word).
 func gengcmask(t *Type, gcmask []byte) {
-	var vec *Bvec
-	var xoffset int64
-	var nptr int64
-	var i int64
-	var j int64
-	var half bool
-	var bits uint8
-	var pos []byte
-
-	for i = 0; i < 16; i++ {
+	for i := int64(0); i < 16; i++ {
 		gcmask[i] = 0
 	}
 	if !haspointers(t) {
@@ -1495,21 +1387,23 @@
 	}
 
 	// Generate compact mask as stacks use.
-	xoffset = 0
+	xoffset := int64(0)
 
-	vec = bvalloc(2 * int32(Widthptr) * 8)
+	vec := bvalloc(2 * int32(Widthptr) * 8)
 	twobitwalktype1(t, &xoffset, vec)
 
 	// Unfold the mask for the GC bitmap format:
 	// 4 bits per word, 2 high bits encode pointer info.
-	pos = gcmask
+	pos := gcmask
 
-	nptr = (t.Width + int64(Widthptr) - 1) / int64(Widthptr)
-	half = false
+	nptr := (t.Width + int64(Widthptr) - 1) / int64(Widthptr)
+	half := false
 
 	// If number of words is odd, repeat the mask.
 	// This makes simpler handling of arrays in runtime.
-	for j = 0; j <= (nptr % 2); j++ {
+	var i int64
+	var bits uint8
+	for j := int64(0); j <= (nptr % 2); j++ {
 		for i = 0; i < nptr; i++ {
 			bits = uint8(bvget(vec, int32(i*obj.BitsPerPointer)) | bvget(vec, int32(i*obj.BitsPerPointer+1))<<1)
 
@@ -1553,16 +1447,13 @@
 
 // Emits insData block from g->data.
 func proggendataflush(g *ProgGen) {
-	var i int32
-	var s int32
-
 	if g.datasize == 0 {
 		return
 	}
 	proggenemit(g, obj.InsData)
 	proggenemit(g, uint8(g.datasize))
-	s = (g.datasize + obj.PointersPerByte - 1) / obj.PointersPerByte
-	for i = 0; i < s; i++ {
+	s := (g.datasize + obj.PointersPerByte - 1) / obj.PointersPerByte
+	for i := int32(0); i < s; i++ {
 		proggenemit(g, g.data[i])
 	}
 	g.datasize = 0
@@ -1579,9 +1470,7 @@
 
 // Skip v bytes due to alignment, etc.
 func proggenskip(g *ProgGen, off int64, v int64) {
-	var i int64
-
-	for i = off; i < off+v; i++ {
+	for i := off; i < off+v; i++ {
 		if (i % int64(Widthptr)) == 0 {
 			proggendata(g, obj.BitsScalar)
 		}
@@ -1612,16 +1501,8 @@
 
 // Generates GC program for large types.
 func gengcprog(t *Type, pgc0 **Sym, pgc1 **Sym) {
-	var gc0 *Sym
-	var gc1 *Sym
-	var nptr int64
-	var size int64
-	var ot int64
-	var xoffset int64
-	var g ProgGen
-
-	nptr = (t.Width + int64(Widthptr) - 1) / int64(Widthptr)
-	size = nptr
+	nptr := (t.Width + int64(Widthptr) - 1) / int64(Widthptr)
+	size := nptr
 	if size%2 != 0 {
 		size *= 2 // repeated twice
 	}
@@ -1633,30 +1514,25 @@
 
 	// Don't generate it if it's too large, runtime will unroll directly into GC bitmap.
 	if size <= obj.MaxGCMask {
-		gc0 = typesymprefix(".gc", t)
+		gc0 := typesymprefix(".gc", t)
 		ggloblsym(gc0, int32(size), obj.DUPOK|obj.NOPTR)
 		*pgc0 = gc0
 	}
 
 	// program in RODATA
-	gc1 = typesymprefix(".gcprog", t)
+	gc1 := typesymprefix(".gcprog", t)
 
+	var g ProgGen
 	proggeninit(&g, gc1)
-	xoffset = 0
+	xoffset := int64(0)
 	gengcprog1(&g, t, &xoffset)
-	ot = proggenfini(&g)
+	ot := proggenfini(&g)
 	ggloblsym(gc1, int32(ot), obj.DUPOK|obj.RODATA)
 	*pgc1 = gc1
 }
 
 // Recursively walks type t and writes GC program into g.
 func gengcprog1(g *ProgGen, t *Type, xoffset *int64) {
-	var fieldoffset int64
-	var i int64
-	var o int64
-	var n int64
-	var t1 *Type
-
 	switch t.Etype {
 	case TINT8,
 		TUINT8,
@@ -1704,16 +1580,16 @@
 			proggendata(g, obj.BitsScalar)
 			proggendata(g, obj.BitsScalar)
 		} else {
-			t1 = t.Type
+			t1 := t.Type
 			if t1.Width == 0 {
 			}
 			// ignore
 			if t.Bound <= 1 || t.Bound*t1.Width < int64(32*Widthptr) {
-				for i = 0; i < t.Bound; i++ {
+				for i := int64(0); i < t.Bound; i++ {
 					gengcprog1(g, t1, xoffset)
 				}
 			} else if !haspointers(t1) {
-				n = t.Width
+				n := t.Width
 				n -= -*xoffset & (int64(Widthptr) - 1) // skip to next ptr boundary
 				proggenarray(g, (n+int64(Widthptr)-1)/int64(Widthptr))
 				proggendata(g, obj.BitsScalar)
@@ -1728,8 +1604,9 @@
 		}
 
 	case TSTRUCT:
-		o = 0
-		for t1 = t.Type; t1 != nil; t1 = t1.Down {
+		o := int64(0)
+		var fieldoffset int64
+		for t1 := t.Type; t1 != nil; t1 = t1.Down {
 			fieldoffset = t1.Width
 			proggenskip(g, *xoffset, fieldoffset-o)
 			*xoffset += fieldoffset - o
diff --git a/src/cmd/internal/gc/reg.go b/src/cmd/internal/gc/reg.go
index 37a394c..42a65da 100644
--- a/src/cmd/internal/gc/reg.go
+++ b/src/cmd/internal/gc/reg.go
@@ -51,11 +51,8 @@
 }
 
 func (x rcmp) Less(i, j int) bool {
-	var p1 *Rgn
-	var p2 *Rgn
-
-	p1 = &x[i]
-	p2 = &x[j]
+	p1 := &x[i]
+	p2 := &x[j]
 	if p1.cost != p2.cost {
 		return int(p2.cost)-int(p1.cost) < 0
 	}
@@ -96,7 +93,6 @@
 
 func walkvardef(n *Node, f *Flow, active int) {
 	var f1 *Flow
-	var f2 *Flow
 	var bn int
 	var v *Var
 
@@ -118,7 +114,7 @@
 		}
 	}
 
-	for f2 = f; f2 != f1; f2 = f2.S1 {
+	for f2 := f; f2 != f1; f2 = f2.S1 {
 		if f2.S2 != nil {
 			walkvardef(n, f2.S2, active)
 		}
@@ -130,23 +126,18 @@
  * just after r
  */
 func addmove(r *Flow, bn int, rn int, f int) {
-	var p *obj.Prog
-	var p1 *obj.Prog
-	var a *obj.Addr
-	var v *Var
-
-	p1 = Ctxt.NewProg()
+	p1 := Ctxt.NewProg()
 	Clearp(p1)
 	p1.Pc = 9999
 
-	p = r.Prog
+	p := r.Prog
 	p1.Link = p.Link
 	p.Link = p1
 	p1.Lineno = p.Lineno
 
-	v = &var_[bn:][0]
+	v := &var_[bn:][0]
 
-	a = &p1.To
+	a := &p1.To
 	a.Offset = v.offset
 	a.Etype = uint8(v.etype)
 	a.Type = obj.TYPE_MEM
@@ -183,11 +174,8 @@
 }
 
 func overlap_reg(o1 int64, w1 int, o2 int64, w2 int) bool {
-	var t1 int64
-	var t2 int64
-
-	t1 = o1 + int64(w1)
-	t2 = o2 + int64(w2)
+	t1 := o1 + int64(w1)
+	t2 := o2 + int64(w2)
 
 	if t1 <= o2 || t2 <= o1 {
 		return false
@@ -201,10 +189,8 @@
 	var i int
 	var n int
 	var et int
-	var z int
 	var flag int
 	var w int64
-	var regu uint64
 	var o int64
 	var bit Bits
 	var node *Node
@@ -222,16 +208,17 @@
 
 	switch a.Type {
 	default:
-		regu = Thearch.Doregbits(int(a.Reg)) | Thearch.RtoB(int(a.Reg)) // TODO: Use RtoB
+		regu := Thearch.Doregbits(int(a.Reg)) | Thearch.RtoB(int(a.Reg)) // TODO: Use RtoB
 		if regu == 0 {
 			goto none
 		}
-		bit = zbits
+		bit := zbits
 		bit.b[0] = regu
 		return bit
 
 		// TODO(rsc): Remove special case here.
 	case obj.TYPE_ADDR:
+		var bit Bits
 		if Thearch.Thechar == '9' || Thearch.Thechar == '5' {
 			goto memcase
 		}
@@ -285,7 +272,7 @@
 	}
 
 	flag = 0
-	for i = 0; i < nvar; i++ {
+	for i := 0; i < nvar; i++ {
 		v = &var_[i:][0]
 		if v.node == node && int(v.name) == n {
 			if v.offset == o {
@@ -324,7 +311,8 @@
 		// having its address taken, so that we keep the whole thing
 		// live at all calls. otherwise we might optimize away part of
 		// a variable but not all of it.
-		for i = 0; i < nvar; i++ {
+		var v *Var
+		for i := 0; i < nvar; i++ {
 			v = &var_[i:][0]
 			if v.node == node {
 				v.addr = 1
@@ -355,23 +343,23 @@
 
 	bit = blsh(uint(i))
 	if n == obj.NAME_EXTERN || n == obj.NAME_STATIC {
-		for z = 0; z < BITS; z++ {
+		for z := 0; z < BITS; z++ {
 			externs.b[z] |= bit.b[z]
 		}
 	}
 	if n == obj.NAME_PARAM {
-		for z = 0; z < BITS; z++ {
+		for z := 0; z < BITS; z++ {
 			params.b[z] |= bit.b[z]
 		}
 	}
 
 	if node.Class == PPARAM {
-		for z = 0; z < BITS; z++ {
+		for z := 0; z < BITS; z++ {
 			ivar.b[z] |= bit.b[z]
 		}
 	}
 	if node.Class == PPARAMOUT {
-		for z = 0; z < BITS; z++ {
+		for z := 0; z < BITS; z++ {
 			ovar.b[z] |= bit.b[z]
 		}
 	}
@@ -420,8 +408,6 @@
 
 func prop(f *Flow, ref Bits, cal Bits) {
 	var f1 *Flow
-	var f2 *Flow
-	var r *Reg
 	var r1 *Reg
 	var z int
 	var i int
@@ -533,6 +519,8 @@
 		f1.Active = 1
 	}
 
+	var r *Reg
+	var f2 *Flow
 	for ; f != f1; f = f.P1 {
 		r = f.Data.(*Reg)
 		for f2 = f.P2; f2 != nil; f2 = f2.P2link {
@@ -542,11 +530,10 @@
 }
 
 func synch(f *Flow, dif Bits) {
-	var f1 *Flow
 	var r1 *Reg
 	var z int
 
-	for f1 = f; f1 != nil; f1 = f1.S1 {
+	for f1 := f; f1 != nil; f1 = f1.S1 {
 		r1 = f1.Data.(*Reg)
 		for z = 0; z < BITS; z++ {
 			dif.b[z] = dif.b[z]&^(^r1.refbehind.b[z]&r1.refahead.b[z]) | r1.set.b[z] | r1.regdiff.b[z]
@@ -570,10 +557,7 @@
 }
 
 func allreg(b uint64, r *Rgn) uint64 {
-	var v *Var
-	var i int
-
-	v = &var_[r.varno:][0]
+	v := &var_[r.varno:][0]
 	r.regno = 0
 	switch v.etype {
 	default:
@@ -593,7 +577,7 @@
 		TBOOL,
 		TPTR32,
 		TPTR64:
-		i = Thearch.BtoR(^b)
+		i := Thearch.BtoR(^b)
 		if i != 0 && r.cost > 0 {
 			r.regno = int16(i)
 			return Thearch.RtoB(i)
@@ -601,7 +585,7 @@
 
 	case TFLOAT32,
 		TFLOAT64:
-		i = Thearch.BtoF(^b)
+		i := Thearch.BtoF(^b)
 		if i != 0 && r.cost > 0 {
 			r.regno = int16(i)
 			return Thearch.FtoB(i)
@@ -620,18 +604,14 @@
 }
 
 func paint1(f *Flow, bn int) {
-	var f1 *Flow
-	var r *Reg
-	var r1 *Reg
-	var z int
-	var bb uint64
-
-	z = bn / 64
-	bb = 1 << uint(bn%64)
-	r = f.Data.(*Reg)
+	z := bn / 64
+	bb := uint64(1 << uint(bn%64))
+	r := f.Data.(*Reg)
 	if r.act.b[z]&bb != 0 {
 		return
 	}
+	var f1 *Flow
+	var r1 *Reg
 	for {
 		if r.refbehind.b[z]&bb == 0 {
 			break
@@ -703,20 +683,15 @@
 }
 
 func paint2(f *Flow, bn int, depth int) uint64 {
-	var f1 *Flow
-	var r *Reg
-	var r1 *Reg
-	var z int
-	var bb uint64
-	var vreg uint64
-
-	z = bn / 64
-	bb = 1 << uint(bn%64)
-	vreg = regbits
-	r = f.Data.(*Reg)
+	z := bn / 64
+	bb := uint64(1 << uint(bn%64))
+	vreg := regbits
+	r := f.Data.(*Reg)
 	if r.act.b[z]&bb == 0 {
 		return vreg
 	}
+	var r1 *Reg
+	var f1 *Flow
 	for {
 		if r.refbehind.b[z]&bb == 0 {
 			break
@@ -779,19 +754,14 @@
 }
 
 func paint3(f *Flow, bn int, rb uint64, rn int) {
-	var f1 *Flow
-	var r *Reg
-	var r1 *Reg
-	var p *obj.Prog
-	var z int
-	var bb uint64
-
-	z = bn / 64
-	bb = 1 << uint(bn%64)
-	r = f.Data.(*Reg)
+	z := bn / 64
+	bb := uint64(1 << uint(bn%64))
+	r := f.Data.(*Reg)
 	if r.act.b[z]&bb != 0 {
 		return
 	}
+	var r1 *Reg
+	var f1 *Flow
 	for {
 		if r.refbehind.b[z]&bb == 0 {
 			break
@@ -814,6 +784,7 @@
 	if LOAD(r, z)&^(r.set.b[z]&^(r.use1.b[z]|r.use2.b[z]))&bb != 0 {
 		addmove(f, bn, rn, 0)
 	}
+	var p *obj.Prog
 	for {
 		r.act.b[z] |= bb
 		p = f.Prog
@@ -886,14 +857,11 @@
 }
 
 func dumpone(f *Flow, isreg int) {
-	var z int
-	var bit Bits
-	var r *Reg
-
 	fmt.Printf("%d:%v", f.Loop, f.Prog)
 	if isreg != 0 {
-		r = f.Data.(*Reg)
-		for z = 0; z < BITS; z++ {
+		r := f.Data.(*Reg)
+		var bit Bits
+		for z := 0; z < BITS; z++ {
 			bit.b[z] = r.set.b[z] | r.use1.b[z] | r.use2.b[z] | r.refbehind.b[z] | r.refahead.b[z] | r.calbehind.b[z] | r.calahead.b[z] | r.regdiff.b[z] | r.act.b[z] | 0
 		}
 		if bany(&bit) {
@@ -932,11 +900,10 @@
 }
 
 func Dumpit(str string, r0 *Flow, isreg int) {
-	var r *Flow
 	var r1 *Flow
 
 	fmt.Printf("\n%s\n", str)
-	for r = r0; r != nil; r = r.Link {
+	for r := r0; r != nil; r = r.Link {
 		dumpone(r, isreg)
 		r1 = r.P2
 		if r1 != nil {
@@ -967,23 +934,6 @@
 }
 
 func regopt(firstp *obj.Prog) {
-	var f *Flow
-	var f1 *Flow
-	var r *Reg
-	var p *obj.Prog
-	var g *Graph
-	var info ProgInfo
-	var i int
-	var z int
-	var active int
-	var vreg uint64
-	var usedreg uint64
-	var mask uint64
-	var nreg int
-	var regnames []string
-	var bit Bits
-	var rgp *Rgn
-
 	if first != 0 {
 		first = 0
 	}
@@ -995,13 +945,14 @@
 	 * than in generated c code.  define pseudo-variables for
 	 * registers, so we have complete register usage information.
 	 */
-	regnames = Thearch.Regnames(&nreg)
+	var nreg int
+	regnames := Thearch.Regnames(&nreg)
 
 	nvar = nreg
-	for i = 0; i < nreg; i++ {
+	for i := 0; i < nreg; i++ {
 		var_[i] = Var{}
 	}
-	for i = 0; i < nreg; i++ {
+	for i := 0; i < nreg; i++ {
 		if regnodes[i] == nil {
 			regnodes[i] = newname(Lookup(regnames[i]))
 		}
@@ -1022,10 +973,10 @@
 	 * allocate pcs
 	 * find use and set of variables
 	 */
-	g = Flowstart(firstp, func() interface{} { return new(Reg) })
+	g := Flowstart(firstp, func() interface{} { return new(Reg) })
 
 	if g == nil {
-		for i = 0; i < nvar; i++ {
+		for i := 0; i < nvar; i++ {
 			var_[i].node.Opt = nil
 		}
 		return
@@ -1033,7 +984,12 @@
 
 	firstf = g.Start
 
-	for f = firstf; f != nil; f = f.Link {
+	var r *Reg
+	var info ProgInfo
+	var p *obj.Prog
+	var bit Bits
+	var z int
+	for f := firstf; f != nil; f = f.Link {
 		p = f.Prog
 		if p.As == obj.AVARDEF || p.As == obj.AVARKILL {
 			continue
@@ -1097,9 +1053,8 @@
 		}
 	}
 
-	for i = 0; i < nvar; i++ {
-		var v *Var
-		v = &var_[i:][0]
+	for i := 0; i < nvar; i++ {
+		v := &var_[i:][0]
 		if v.addr != 0 {
 			bit = blsh(uint(i))
 			for z = 0; z < BITS; z++ {
@@ -1133,15 +1088,15 @@
 	 * (r->act will be reused in pass 5 for something else,
 	 * but we'll be done with it by then.)
 	 */
-	active = 0
+	active := 0
 
-	for f = firstf; f != nil; f = f.Link {
+	for f := firstf; f != nil; f = f.Link {
 		f.Active = 0
 		r = f.Data.(*Reg)
 		r.act = zbits
 	}
 
-	for f = firstf; f != nil; f = f.Link {
+	for f := firstf; f != nil; f = f.Link {
 		p = f.Prog
 		if p.As == obj.AVARDEF && Isfat(((p.To.Node).(*Node)).Type) && ((p.To.Node).(*Node)).Opt != nil {
 			active++
@@ -1154,6 +1109,9 @@
 	 * iterate propagating usage
 	 * 	back until flow graph is complete
 	 */
+	var f1 *Flow
+	var i int
+	var f *Flow
 loop1:
 	change = 0
 
@@ -1213,8 +1171,8 @@
 	 * pass 4.5
 	 * move register pseudo-variables into regu.
 	 */
-	mask = (1 << uint(nreg)) - 1
-	for f = firstf; f != nil; f = f.Link {
+	mask := uint64((1 << uint(nreg)) - 1)
+	for f := firstf; f != nil; f = f.Link {
 		r = f.Data.(*Reg)
 		r.regu = (r.refbehind.b[0] | r.set.b[0]) & mask
 		r.set.b[0] &^= mask
@@ -1240,8 +1198,8 @@
 	f = firstf
 
 	if f != nil {
-		r = f.Data.(*Reg)
-		for z = 0; z < BITS; z++ {
+		r := f.Data.(*Reg)
+		for z := 0; z < BITS; z++ {
 			bit.b[z] = (r.refahead.b[z] | r.calahead.b[z]) &^ (externs.b[z] | params.b[z] | addrs.b[z] | consts.b[z])
 		}
 		if bany(&bit) && f.Refset == 0 {
@@ -1253,11 +1211,12 @@
 		}
 	}
 
-	for f = firstf; f != nil; f = f.Link {
+	for f := firstf; f != nil; f = f.Link {
 		(f.Data.(*Reg)).act = zbits
 	}
 	nregion = 0
-	for f = firstf; f != nil; f = f.Link {
+	var rgp *Rgn
+	for f := firstf; f != nil; f = f.Link {
 		r = f.Data.(*Reg)
 		for z = 0; z < BITS; z++ {
 			bit.b[z] = r.set.b[z] &^ (r.refahead.b[z] | r.calahead.b[z] | addrs.b[z])
@@ -1311,7 +1270,9 @@
 	if Debug['R'] != 0 && Debug['v'] != 0 {
 		fmt.Printf("\nregisterizing\n")
 	}
-	for i = 0; i < nregion; i++ {
+	var usedreg uint64
+	var vreg uint64
+	for i := 0; i < nregion; i++ {
 		rgp = &region[i]
 		if Debug['R'] != 0 && Debug['v'] != 0 {
 			fmt.Printf("region %d: cost %d varno %d enter %d\n", i, rgp.cost, rgp.varno, rgp.enter.Prog.Pc)
@@ -1321,9 +1282,7 @@
 		vreg = allreg(usedreg, rgp)
 		if rgp.regno != 0 {
 			if Debug['R'] != 0 && Debug['v'] != 0 {
-				var v *Var
-
-				v = &var_[rgp.varno:][0]
+				v := &var_[rgp.varno:][0]
 				fmt.Printf("registerize %v+%d (bit=%2d et=%v) in %v usedreg=%#x vreg=%#x\n", Nconv(v.node, 0), v.offset, rgp.varno, Econv(int(v.etype), 0), Ctxt.Rconv(int(rgp.regno)), usedreg, vreg)
 			}
 
@@ -1334,7 +1293,7 @@
 	/*
 	 * free aux structures. peep allocates new ones.
 	 */
-	for i = 0; i < nvar; i++ {
+	for i := 0; i < nvar; i++ {
 		var_[i].node.Opt = nil
 	}
 	Flowend(g)
@@ -1342,7 +1301,7 @@
 
 	if Debug['R'] != 0 && Debug['v'] != 0 {
 		// Rebuild flow graph, since we inserted instructions
-		g = Flowstart(firstp, nil)
+		g := Flowstart(firstp, nil)
 
 		firstf = g.Start
 		Dumpit("pass6", firstf, 0)
@@ -1361,7 +1320,7 @@
 	/*
 	 * eliminate nops
 	 */
-	for p = firstp; p != nil; p = p.Link {
+	for p := firstp; p != nil; p = p.Link {
 		for p.Link != nil && p.Link.As == obj.ANOP {
 			p.Link = p.Link.Link
 		}
diff --git a/src/cmd/internal/gc/select.go b/src/cmd/internal/gc/select.go
index ab7a144..ca6a21d 100644
--- a/src/cmd/internal/gc/select.go
+++ b/src/cmd/internal/gc/select.go
@@ -10,16 +10,12 @@
 func typecheckselect(sel *Node) {
 	var ncase *Node
 	var n *Node
-	var def *Node
-	var l *NodeList
-	var lno int
-	var count int
 
-	def = nil
-	lno = int(setlineno(sel))
-	count = 0
+	def := (*Node)(nil)
+	lno := int(setlineno(sel))
+	count := 0
 	typechecklist(sel.Ninit, Etop)
-	for l = sel.List; l != nil; l = l.Next {
+	for l := sel.List; l != nil; l = l.Next {
 		count++
 		ncase = l.N
 		setlineno(ncase)
@@ -94,27 +90,20 @@
 }
 
 func walkselect(sel *Node) {
-	var lno int
-	var i int
-	var n *Node
-	var r *Node
-	var a *Node
-	var var_ *Node
-	var selv *Node
-	var cas *Node
-	var dflt *Node
-	var ch *Node
-	var l *NodeList
-	var init *NodeList
-
 	if sel.List == nil && sel.Xoffset != 0 {
 		Fatal("double walkselect") // already rewrote
 	}
 
-	lno = int(setlineno(sel))
-	i = count(sel.List)
+	lno := int(setlineno(sel))
+	i := count(sel.List)
 
 	// optimization: zero-case select
+	var init *NodeList
+	var r *Node
+	var n *Node
+	var var_ *Node
+	var selv *Node
+	var cas *Node
 	if i == 0 {
 		sel.Nbody = list1(mkcall("block", nil, nil))
 		goto out
@@ -124,13 +113,14 @@
 	// TODO(rsc): Reenable optimization once order.c can handle it.
 	// golang.org/issue/7672.
 	if i == 1 {
-		cas = sel.List.N
+		cas := sel.List.N
 		setlineno(cas)
-		l = cas.Ninit
+		l := cas.Ninit
 		if cas.Left != nil { // not default:
-			n = cas.Left
+			n := cas.Left
 			l = concat(l, n.Ninit)
 			n.Ninit = nil
+			var ch *Node
 			switch n.Op {
 			default:
 				Fatal("select %v", Oconv(int(n.Op), 0))
@@ -167,7 +157,7 @@
 			}
 
 			// if ch == nil { block() }; n;
-			a = Nod(OIF, nil, nil)
+			a := Nod(OIF, nil, nil)
 
 			a.Ntest = Nod(OEQ, ch, nodnil())
 			a.Nbody = list1(mkcall("block", nil, &l))
@@ -183,7 +173,7 @@
 
 	// convert case value arguments to addresses.
 	// this rewrite is used by both the general code and the next optimization.
-	for l = sel.List; l != nil; l = l.Next {
+	for l := sel.List; l != nil; l = l.Next {
 		cas = l.N
 		setlineno(cas)
 		n = cas.Left
@@ -216,6 +206,8 @@
 
 	// optimization: two-case select but one is default: single non-blocking op.
 	if i == 2 && (sel.List.N.Left == nil || sel.List.Next.N.Left == nil) {
+		var cas *Node
+		var dflt *Node
 		if sel.List.N.Left == nil {
 			cas = sel.List.Next.N
 			dflt = sel.List.N
@@ -224,9 +216,9 @@
 			cas = sel.List.N
 		}
 
-		n = cas.Left
+		n := cas.Left
 		setlineno(n)
-		r = Nod(OIF, nil, nil)
+		r := Nod(OIF, nil, nil)
 		r.Ninit = cas.Ninit
 		switch n.Op {
 		default:
@@ -234,7 +226,7 @@
 
 			// if selectnbsend(c, v) { body } else { default body }
 		case OSEND:
-			ch = n.Left
+			ch := n.Left
 
 			r.Ntest = mkcall1(chanfn("selectnbsend", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), ch, n.Right)
 
@@ -243,7 +235,7 @@
 			r = Nod(OIF, nil, nil)
 
 			r.Ninit = cas.Ninit
-			ch = n.Right.Left
+			ch := n.Right.Left
 			r.Ntest = mkcall1(chanfn("selectnbrecv", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, ch)
 
 			// if c != nil && selectnbrecv2(&v, c) { body } else { default body }
@@ -251,7 +243,7 @@
 			r = Nod(OIF, nil, nil)
 
 			r.Ninit = cas.Ninit
-			ch = n.Right.Left
+			ch := n.Right.Left
 			r.Ntest = mkcall1(chanfn("selectnbrecv2", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, n.Ntest, ch)
 		}
 
@@ -278,7 +270,7 @@
 	init = list(init, r)
 
 	// register cases
-	for l = sel.List; l != nil; l = l.Next {
+	for l := sel.List; l != nil; l = l.Next {
 		cas = l.N
 		setlineno(cas)
 		n = cas.Left
@@ -334,14 +326,9 @@
 
 // Keep in sync with src/runtime/chan.h.
 func selecttype(size int32) *Type {
-	var sel *Node
-	var sudog *Node
-	var scase *Node
-	var arr *Node
-
 	// TODO(dvyukov): it's possible to generate SudoG and Scase only once
 	// and then cache; and also cache Select per size.
-	sudog = Nod(OTSTRUCT, nil, nil)
+	sudog := Nod(OTSTRUCT, nil, nil)
 
 	sudog.List = list(sudog.List, Nod(ODCLFIELD, newname(Lookup("g")), typenod(Ptrto(Types[TUINT8]))))
 	sudog.List = list(sudog.List, Nod(ODCLFIELD, newname(Lookup("selectdone")), typenod(Ptrto(Types[TUINT8]))))
@@ -355,7 +342,7 @@
 	sudog.Type.Noalg = 1
 	sudog.Type.Local = 1
 
-	scase = Nod(OTSTRUCT, nil, nil)
+	scase := Nod(OTSTRUCT, nil, nil)
 	scase.List = list(scase.List, Nod(ODCLFIELD, newname(Lookup("elem")), typenod(Ptrto(Types[TUINT8]))))
 	scase.List = list(scase.List, Nod(ODCLFIELD, newname(Lookup("chan")), typenod(Ptrto(Types[TUINT8]))))
 	scase.List = list(scase.List, Nod(ODCLFIELD, newname(Lookup("pc")), typenod(Types[TUINTPTR])))
@@ -367,12 +354,12 @@
 	scase.Type.Noalg = 1
 	scase.Type.Local = 1
 
-	sel = Nod(OTSTRUCT, nil, nil)
+	sel := Nod(OTSTRUCT, nil, nil)
 	sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("tcase")), typenod(Types[TUINT16])))
 	sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("ncase")), typenod(Types[TUINT16])))
 	sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("pollorder")), typenod(Ptrto(Types[TUINT8]))))
 	sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("lockorder")), typenod(Ptrto(Types[TUINT8]))))
-	arr = Nod(OTARRAY, Nodintconst(int64(size)), scase)
+	arr := Nod(OTARRAY, Nodintconst(int64(size)), scase)
 	sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("scase")), arr))
 	arr = Nod(OTARRAY, Nodintconst(int64(size)), typenod(Ptrto(Types[TUINT8])))
 	sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("lockorderarr")), arr))
diff --git a/src/cmd/internal/gc/sinit.go b/src/cmd/internal/gc/sinit.go
index 57422b4..ca8db418 100644
--- a/src/cmd/internal/gc/sinit.go
+++ b/src/cmd/internal/gc/sinit.go
@@ -23,15 +23,12 @@
 // init1 walks the AST starting at n, and accumulates in out
 // the list of definitions needing init code in dependency order.
 func init1(n *Node, out **NodeList) {
-	var l *NodeList
-	var nv *Node
-
 	if n == nil {
 		return
 	}
 	init1(n.Left, out)
 	init1(n.Right, out)
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		init1(l.N, out)
 	}
 
@@ -72,12 +69,13 @@
 		// Conversely, if there exists an initialization cycle involving
 		// a variable in the program, the tree walk will reach a cycle
 		// involving that variable.
+		var nv *Node
 		if n.Class != PFUNC {
 			nv = n
 			goto foundinitloop
 		}
 
-		for l = initlist; l.N != n; l = l.Next {
+		for l := initlist; l.N != n; l = l.Next {
 			if l.N.Class != PFUNC {
 				nv = l.N
 				goto foundinitloop
@@ -103,13 +101,14 @@
 		fmt.Printf("%v: initialization loop:\n", nv.Line())
 
 		// Build back pointers in initlist.
-		for l = initlist; l != nil; l = l.Next {
+		for l := initlist; l != nil; l = l.Next {
 			if l.Next != nil {
 				l.Next.End = l
 			}
 		}
 
 		// Print nv -> ... -> n1 -> n.
+		var l *NodeList
 		for l = initlist; l.N != nv; l = l.Next {
 		}
 		for ; l != nil; l = l.End {
@@ -129,7 +128,7 @@
 	// reached a new unvisited node.
 	n.Initorder = InitPending
 
-	l = new(NodeList)
+	l := new(NodeList)
 	if l == nil {
 		Flusherrors()
 		Yyerror("out of memory")
@@ -181,7 +180,7 @@
 				break
 			}
 			n.Defn.Initorder = InitDone
-			for l = n.Defn.Rlist; l != nil; l = l.Next {
+			for l := n.Defn.Rlist; l != nil; l = l.Next {
 				init1(l.N, out)
 			}
 			if Debug['%'] != 0 {
@@ -261,11 +260,8 @@
 // declarations and outputs the corresponding list of statements
 // to include in the init() function body.
 func initfix(l *NodeList) *NodeList {
-	var lout *NodeList
-	var lno int
-
-	lout = nil
-	lno = int(lineno)
+	lout := (*NodeList)(nil)
+	lno := int(lineno)
 	initreorder(l, &lout)
 	lineno = int32(lno)
 	return lout
@@ -276,31 +272,19 @@
  * into DATA statements if at all possible.
  */
 func staticinit(n *Node, out **NodeList) bool {
-	var l *Node
-	var r *Node
-
 	if n.Op != ONAME || n.Class != PEXTERN || n.Defn == nil || n.Defn.Op != OAS {
 		Fatal("staticinit")
 	}
 
 	lineno = n.Lineno
-	l = n.Defn.Left
-	r = n.Defn.Right
+	l := n.Defn.Left
+	r := n.Defn.Right
 	return staticassign(l, r, out)
 }
 
 // like staticassign but we are copying an already
 // initialized value r.
 func staticcopy(l *Node, r *Node, out **NodeList) bool {
-	var i int
-	var e *InitEntry
-	var p *InitPlan
-	var a *Node
-	var ll *Node
-	var rr *Node
-	var orig *Node
-	var n1 Node
-
 	if r.Op != ONAME || r.Class != PEXTERN || r.Sym.Pkg != localpkg {
 		return false
 	}
@@ -310,7 +294,7 @@
 	if r.Defn.Op != OAS {
 		return false
 	}
-	orig = r
+	orig := r
 	r = r.Defn.Right
 
 	switch r.Op {
@@ -353,9 +337,9 @@
 	case OARRAYLIT:
 		if Isslice(r.Type) {
 			// copy slice
-			a = r.Nname
+			a := r.Nname
 
-			n1 = *l
+			n1 := *l
 			n1.Xoffset = l.Xoffset + int64(Array_array)
 			gdata(&n1, Nod(OADDR, a, nil), Widthptr)
 			n1.Xoffset = l.Xoffset + int64(Array_nel)
@@ -368,10 +352,13 @@
 
 		// fall through
 	case OSTRUCTLIT:
-		p = r.Initplan
+		p := r.Initplan
 
-		n1 = *l
-		for i = 0; i < len(p.E); i++ {
+		n1 := *l
+		var e *InitEntry
+		var ll *Node
+		var rr *Node
+		for i := 0; i < len(p.E); i++ {
 			e = &p.E[i]
 			n1.Xoffset = l.Xoffset + e.Xoffset
 			n1.Type = e.Expr.Type
@@ -402,14 +389,7 @@
 }
 
 func staticassign(l *Node, r *Node, out **NodeList) bool {
-	var a *Node
 	var n1 Node
-	var nam Node
-	var ta *Type
-	var p *InitPlan
-	var e *InitEntry
-	var i int
-	var sval *Strlit
 
 	switch r.Op {
 	//dump("not static", r);
@@ -429,8 +409,9 @@
 		return true
 
 	case OADDR:
+		var nam Node
 		if stataddr(&nam, r.Left) {
-			n1 = *r
+			n1 := *r
 			n1.Left = &nam
 			gdata(l, &n1, int(l.Type.Width))
 			return true
@@ -447,7 +428,7 @@
 		case OARRAYLIT,
 			OMAPLIT,
 			OSTRUCTLIT:
-			a = staticname(r.Left.Type, 1)
+			a := staticname(r.Left.Type, 1)
 
 			r.Nname = a
 			gdata(l, Nod(OADDR, a, nil), int(l.Type.Width))
@@ -461,7 +442,7 @@
 
 	case OSTRARRAYBYTE:
 		if l.Class == PEXTERN && r.Left.Op == OLITERAL {
-			sval = r.Left.Val.U.Sval
+			sval := r.Left.Val.U.Sval
 			slicebytes(l, sval.S, len(sval.S))
 			return true
 		}
@@ -470,11 +451,11 @@
 		initplan(r)
 		if Isslice(r.Type) {
 			// Init slice.
-			ta = typ(TARRAY)
+			ta := typ(TARRAY)
 
 			ta.Type = r.Type.Type
 			ta.Bound = Mpgetfix(r.Right.Val.U.Xval)
-			a = staticname(ta, 1)
+			a := staticname(ta, 1)
 			r.Nname = a
 			n1 = *l
 			n1.Xoffset = l.Xoffset + int64(Array_array)
@@ -493,9 +474,11 @@
 	case OSTRUCTLIT:
 		initplan(r)
 
-		p = r.Initplan
+		p := r.Initplan
 		n1 = *l
-		for i = 0; i < len(p.E); i++ {
+		var e *InitEntry
+		var a *Node
+		for i := 0; i < len(p.E); i++ {
 			e = &p.E[i]
 			n1.Xoffset = l.Xoffset + e.Xoffset
 			n1.Type = e.Expr.Type
@@ -529,11 +512,9 @@
  * part of the composite literal.
  */
 func staticname(t *Type, ctxt int) *Node {
-	var n *Node
-
 	namebuf = fmt.Sprintf("statictmp_%.4d", statuniqgen)
 	statuniqgen++
-	n = newname(Lookup(namebuf))
+	n := newname(Lookup(namebuf))
 	if ctxt == 0 {
 		n.Readonly = 1
 	}
@@ -570,9 +551,7 @@
 }
 
 func litas(l *Node, r *Node, init **NodeList) {
-	var a *Node
-
-	a = Nod(OAS, l, r)
+	a := Nod(OAS, l, r)
 	typecheck(&a, Etop)
 	walkexpr(&a, init)
 	*init = list(*init, a)
@@ -584,11 +563,7 @@
 )
 
 func getdyn(n *Node, top int) int {
-	var nl *NodeList
-	var value *Node
-	var mode int
-
-	mode = 0
+	mode := 0
 	switch n.Op {
 	default:
 		if isliteral(n) {
@@ -606,7 +581,8 @@
 		break
 	}
 
-	for nl = n.List; nl != nil; nl = nl.Next {
+	var value *Node
+	for nl := n.List; nl != nil; nl = nl.Next {
 		value = nl.N.Right
 		mode |= getdyn(value, 0)
 		if mode == MODEDYNAM|MODECONST {
@@ -620,11 +596,10 @@
 func structlit(ctxt int, pass int, n *Node, var_ *Node, init **NodeList) {
 	var r *Node
 	var a *Node
-	var nl *NodeList
 	var index *Node
 	var value *Node
 
-	for nl = n.List; nl != nil; nl = nl.Next {
+	for nl := n.List; nl != nil; nl = nl.Next {
 		r = nl.N
 		if r.Op != OKEY {
 			Fatal("structlit: rhs not OKEY: %v", Nconv(r, 0))
@@ -688,11 +663,10 @@
 func arraylit(ctxt int, pass int, n *Node, var_ *Node, init **NodeList) {
 	var r *Node
 	var a *Node
-	var l *NodeList
 	var index *Node
 	var value *Node
 
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		r = l.N
 		if r.Op != OKEY {
 			Fatal("arraylit: rhs not OKEY: %v", Nconv(r, 0))
@@ -754,18 +728,8 @@
 }
 
 func slicelit(ctxt int, n *Node, var_ *Node, init **NodeList) {
-	var r *Node
-	var a *Node
-	var l *NodeList
-	var t *Type
-	var vstat *Node
-	var vauto *Node
-	var index *Node
-	var value *Node
-	var mode int
-
 	// make an array type
-	t = shallow(n.Type)
+	t := shallow(n.Type)
 
 	t.Bound = Mpgetfix(n.Right.Val.U.Xval)
 	t.Width = 0
@@ -775,13 +739,13 @@
 
 	if ctxt != 0 {
 		// put everything into static array
-		vstat = staticname(t, ctxt)
+		vstat := staticname(t, ctxt)
 
 		arraylit(ctxt, 1, n, vstat, init)
 		arraylit(ctxt, 2, n, vstat, init)
 
 		// copy static to slice
-		a = Nod(OSLICE, vstat, Nod(OKEY, nil, nil))
+		a := Nod(OSLICE, vstat, Nod(OKEY, nil, nil))
 
 		a = Nod(OAS, var_, a)
 		typecheck(&a, Etop)
@@ -811,18 +775,19 @@
 
 	// if the literal contains constants,
 	// make static initialized array (1),(2)
-	vstat = nil
+	vstat := (*Node)(nil)
 
-	mode = getdyn(n, 1)
+	mode := getdyn(n, 1)
 	if mode&MODECONST != 0 {
 		vstat = staticname(t, ctxt)
 		arraylit(ctxt, 1, n, vstat, init)
 	}
 
 	// make new auto *array (3 declare)
-	vauto = temp(Ptrto(t))
+	vauto := temp(Ptrto(t))
 
 	// set auto to point at new temp or heap (3 assign)
+	var a *Node
 	if n.Alloc != nil {
 		// temp allocated during order.c for dddarg
 		n.Alloc.Type = t
@@ -873,7 +838,10 @@
 	*init = list(*init, a)
 
 	// put dynamics into slice (6)
-	for l = n.List; l != nil; l = l.Next {
+	var value *Node
+	var r *Node
+	var index *Node
+	for l := n.List; l != nil; l = l.Next {
 		r = l.N
 		if r.Op != OKEY {
 			Fatal("slicelit: rhs not OKEY: %v", Nconv(r, 0))
@@ -914,35 +882,22 @@
 
 func maplit(ctxt int, n *Node, var_ *Node, init **NodeList) {
 	var r *Node
-	var a *Node
-	var l *NodeList
-	var nerr int
-	var b int64
-	var t *Type
-	var tk *Type
-	var tv *Type
-	var t1 *Type
-	var vstat *Node
 	var index *Node
 	var value *Node
-	var key *Node
-	var val *Node
-	var syma *Sym
-	var symb *Sym
 
 	ctxt = 0
 
 	// make the map var
-	nerr = nerrors
+	nerr := nerrors
 
-	a = Nod(OMAKE, nil, nil)
+	a := Nod(OMAKE, nil, nil)
 	a.List = list1(typenod(n.Type))
 	litas(var_, a, init)
 
 	// count the initializers
-	b = 0
+	b := int64(0)
 
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		r = l.N
 
 		if r.Op != OKEY {
@@ -958,18 +913,18 @@
 
 	if b != 0 {
 		// build type [count]struct { a Tindex, b Tvalue }
-		t = n.Type
+		t := n.Type
 
-		tk = t.Down
-		tv = t.Type
+		tk := t.Down
+		tv := t.Type
 
-		symb = Lookup("b")
+		symb := Lookup("b")
 		t = typ(TFIELD)
 		t.Type = tv
 		t.Sym = symb
 
-		syma = Lookup("a")
-		t1 = t
+		syma := Lookup("a")
+		t1 := t
 		t = typ(TFIELD)
 		t.Type = tk
 		t.Sym = syma
@@ -987,10 +942,13 @@
 		dowidth(t)
 
 		// make and initialize static array
-		vstat = staticname(t, ctxt)
+		vstat := staticname(t, ctxt)
 
-		b = 0
-		for l = n.List; l != nil; l = l.Next {
+		b := int64(0)
+		var index *Node
+		var r *Node
+		var value *Node
+		for l := n.List; l != nil; l = l.Next {
 			r = l.N
 
 			if r.Op != OKEY {
@@ -1056,10 +1014,10 @@
 	}
 
 	// put in dynamic entries one-at-a-time
-	key = nil
+	key := (*Node)(nil)
 
-	val = nil
-	for l = n.List; l != nil; l = l.Next {
+	val := (*Node)(nil)
+	for l := n.List; l != nil; l = l.Next {
 		r = l.N
 
 		if r.Op != OKEY {
@@ -1109,12 +1067,7 @@
 }
 
 func anylit(ctxt int, n *Node, var_ *Node, init **NodeList) {
-	var t *Type
-	var a *Node
-	var vstat *Node
-	var r *Node
-
-	t = n.Type
+	t := n.Type
 	switch n.Op {
 	default:
 		Fatal("anylit: not lit")
@@ -1124,6 +1077,7 @@
 			Fatal("anylit: not ptr")
 		}
 
+		var r *Node
 		if n.Right != nil {
 			r = Nod(OADDR, n.Right, nil)
 			typecheck(&r, Erv)
@@ -1135,7 +1089,7 @@
 		}
 
 		walkexpr(&r, init)
-		a = Nod(OAS, var_, r)
+		a := Nod(OAS, var_, r)
 
 		typecheck(&a, Etop)
 		*init = list(*init, a)
@@ -1152,12 +1106,12 @@
 		if simplename(var_) && count(n.List) > 4 {
 			if ctxt == 0 {
 				// lay out static data
-				vstat = staticname(t, ctxt)
+				vstat := staticname(t, ctxt)
 
 				structlit(ctxt, 1, n, vstat, init)
 
 				// copy static to var
-				a = Nod(OAS, var_, vstat)
+				a := Nod(OAS, var_, vstat)
 
 				typecheck(&a, Etop)
 				walkexpr(&a, init)
@@ -1176,7 +1130,7 @@
 
 		// initialize of not completely specified
 		if simplename(var_) || count(n.List) < structcount(t) {
-			a = Nod(OAS, var_, nil)
+			a := Nod(OAS, var_, nil)
 			typecheck(&a, Etop)
 			walkexpr(&a, init)
 			*init = list(*init, a)
@@ -1196,12 +1150,12 @@
 		if simplename(var_) && count(n.List) > 4 {
 			if ctxt == 0 {
 				// lay out static data
-				vstat = staticname(t, ctxt)
+				vstat := staticname(t, ctxt)
 
 				arraylit(1, 1, n, vstat, init)
 
 				// copy static to automatic
-				a = Nod(OAS, var_, vstat)
+				a := Nod(OAS, var_, vstat)
 
 				typecheck(&a, Etop)
 				walkexpr(&a, init)
@@ -1220,7 +1174,7 @@
 
 		// initialize of not completely specified
 		if simplename(var_) || int64(count(n.List)) < t.Bound {
-			a = Nod(OAS, var_, nil)
+			a := Nod(OAS, var_, nil)
 			typecheck(&a, Etop)
 			walkexpr(&a, init)
 			*init = list(*init, a)
@@ -1289,8 +1243,6 @@
 }
 
 func stataddr(nam *Node, n *Node) bool {
-	var l int
-
 	if n == nil {
 		goto no
 	}
@@ -1315,7 +1267,7 @@
 		if !stataddr(nam, n.Left) {
 			break
 		}
-		l = getlit(n.Right)
+		l := getlit(n.Right)
 		if l < 0 {
 			break
 		}
@@ -1334,21 +1286,18 @@
 }
 
 func initplan(n *Node) {
-	var p *InitPlan
-	var a *Node
-	var l *NodeList
-
 	if n.Initplan != nil {
 		return
 	}
-	p = new(InitPlan)
+	p := new(InitPlan)
 	n.Initplan = p
 	switch n.Op {
 	default:
 		Fatal("initplan")
 
 	case OARRAYLIT:
-		for l = n.List; l != nil; l = l.Next {
+		var a *Node
+		for l := n.List; l != nil; l = l.Next {
 			a = l.N
 			if a.Op != OKEY || !Smallintconst(a.Left) {
 				Fatal("initplan arraylit")
@@ -1357,7 +1306,8 @@
 		}
 
 	case OSTRUCTLIT:
-		for l = n.List; l != nil; l = l.Next {
+		var a *Node
+		for l := n.List; l != nil; l = l.Next {
 			a = l.N
 			if a.Op != OKEY || a.Left.Type == nil {
 				Fatal("initplan structlit")
@@ -1366,7 +1316,8 @@
 		}
 
 	case OMAPLIT:
-		for l = n.List; l != nil; l = l.Next {
+		var a *Node
+		for l := n.List; l != nil; l = l.Next {
 			a = l.N
 			if a.Op != OKEY {
 				Fatal("initplan maplit")
@@ -1377,10 +1328,6 @@
 }
 
 func addvalue(p *InitPlan, xoffset int64, key *Node, n *Node) {
-	var i int
-	var q *InitPlan
-	var e *InitEntry
-
 	// special case: zero can be dropped entirely
 	if iszero(n) {
 		p.Zero += n.Type.Width
@@ -1390,8 +1337,9 @@
 	// special case: inline struct and array (not slice) literals
 	if isvaluelit(n) {
 		initplan(n)
-		q = n.Initplan
-		for i = 0; i < len(q.E); i++ {
+		q := n.Initplan
+		var e *InitEntry
+		for i := 0; i < len(q.E); i++ {
 			e = entry(p)
 			*e = q.E[i]
 			e.Xoffset += xoffset
@@ -1407,14 +1355,12 @@
 		p.Expr += n.Type.Width
 	}
 
-	e = entry(p)
+	e := entry(p)
 	e.Xoffset = xoffset
 	e.Expr = n
 }
 
 func iszero(n *Node) bool {
-	var l *NodeList
-
 	switch n.Op {
 	case OLITERAL:
 		switch n.Val.Ctype {
@@ -1450,7 +1396,7 @@
 
 		// fall through
 	case OSTRUCTLIT:
-		for l = n.List; l != nil; l = l.Next {
+		for l := n.List; l != nil; l = l.Next {
 			if !iszero(l.N.Right) {
 				return false
 			}
@@ -1483,6 +1429,7 @@
 	nr = n.Right
 	nl = n.Left
 	if nr == nil {
+		var nam Node
 		if !stataddr(&nam, nl) {
 			goto no
 		}
diff --git a/src/cmd/internal/gc/subr.go b/src/cmd/internal/gc/subr.go
index dba7dc3..f7c07584 100644
--- a/src/cmd/internal/gc/subr.go
+++ b/src/cmd/internal/gc/subr.go
@@ -44,12 +44,10 @@
 }
 
 func adderrorname(n *Node) {
-	var old string
-
 	if n.Op != ODOT {
 		return
 	}
-	old = fmt.Sprintf("%v: undefined: %v\n", n.Line(), Nconv(n.Left, 0))
+	old := fmt.Sprintf("%v: undefined: %v\n", n.Line(), Nconv(n.Left, 0))
 	if len(errors) > 0 && int32(errors[len(errors)-1].lineno) == n.Lineno && errors[len(errors)-1].msg == old {
 		errors[len(errors)-1].msg = fmt.Sprintf("%v: undefined: %v in %v\n", n.Line(), Nconv(n.Left, 0), Nconv(n, 0))
 	}
@@ -74,11 +72,8 @@
 }
 
 func (x errcmp) Less(i, j int) bool {
-	var a *Error
-	var b *Error
-
-	a = &x[i]
-	b = &x[j]
+	a := &x[i]
+	b := &x[j]
 	if a.lineno != b.lineno {
 		return a.lineno-b.lineno < 0
 	}
@@ -89,14 +84,12 @@
 }
 
 func Flusherrors() {
-	var i int
-
 	obj.Bflush(&bstdout)
 	if len(errors) == 0 {
 		return
 	}
 	sort.Sort(errcmp(errors[:len(errors)]))
-	for i = 0; i < len(errors); i++ {
+	for i := 0; i < len(errors); i++ {
 		if i == 0 || errors[i].msg != errors[i-1].msg {
 			fmt.Printf("%s", errors[i].msg)
 		}
@@ -134,8 +127,6 @@
 var yyerror_lastsyntax int
 
 func Yyerror(fmt_ string, args ...interface{}) {
-	var i int
-
 	if fmt_ == "%s" && len(args) == 1 && args[0] == "syntax error" {
 		nsyntaxerrors++
 	}
@@ -169,7 +160,7 @@
 		}
 
 		// look for parse state-specific errors in list (see go.errors).
-		for i = 0; i < len(yymsg); i++ {
+		for i := 0; i < len(yymsg); i++ {
 			if yymsg[i].yystate == yystate && yymsg[i].yychar == yychar_subr {
 				yyerrorl(int(lexlineno), "syntax error: %s", yymsg[i].msg)
 				return
@@ -204,7 +195,6 @@
 }
 
 func Warn(fmt_ string, args ...interface{}) {
-
 	adderr(parserline(), fmt_, args)
 
 	hcrash()
@@ -218,7 +208,6 @@
 }
 
 func Fatal(fmt_ string, args ...interface{}) {
-
 	Flusherrors()
 
 	fmt.Printf("%v: internal compiler error: ", Ctxt.Line(int(lineno)))
@@ -259,9 +248,7 @@
 }
 
 func setlineno(n *Node) int32 {
-	var lno int32
-
-	lno = lineno
+	lno := lineno
 	if n != nil {
 		switch n.Op {
 		case ONAME,
@@ -285,10 +272,9 @@
 }
 
 func stringhash(p string) uint32 {
-	var h uint32
 	var c int
 
-	h = 0
+	h := uint32(0)
 	for {
 		c, p = intstarstringplusplus(p)
 		if c == 0 {
@@ -312,13 +298,9 @@
 }
 
 func Pkglookup(name string, pkg *Pkg) *Sym {
-	var s *Sym
-	var h uint32
-	var c int
-
-	h = stringhash(name) % NHASH
-	c = int(name[0])
-	for s = hash[h]; s != nil; s = s.Link {
+	h := stringhash(name) % NHASH
+	c := int(name[0])
+	for s := hash[h]; s != nil; s = s.Link {
 		if int(s.Name[0]) != c || s.Pkg != pkg {
 			continue
 		}
@@ -327,7 +309,7 @@
 		}
 	}
 
-	s = new(Sym)
+	s := new(Sym)
 	s.Name = name
 
 	s.Pkg = pkg
@@ -351,12 +333,10 @@
 func importdot(opkg *Pkg, pack *Node) {
 	var s *Sym
 	var s1 *Sym
-	var h uint32
-	var n int
 	var pkgerror string
 
-	n = 0
-	for h = 0; h < NHASH; h++ {
+	n := 0
+	for h := uint32(0); h < NHASH; h++ {
 		for s = hash[h]; s != nil; s = s.Link {
 			if s.Pkg != opkg {
 				continue
@@ -389,14 +369,11 @@
 }
 
 func gethunk() {
-	var h string
-	var nh int32
-
-	nh = NHUNK
+	nh := int32(NHUNK)
 	if thunk >= 10*NHUNK {
 		nh = 10 * NHUNK
 	}
-	h = string(make([]byte, nh))
+	h := string(make([]byte, nh))
 	if h == "" {
 		Flusherrors()
 		Yyerror("out of memory")
@@ -409,9 +386,7 @@
 }
 
 func Nod(op int, nleft *Node, nright *Node) *Node {
-	var n *Node
-
-	n = new(Node)
+	n := new(Node)
 	n.Op = uint8(op)
 	n.Left = nleft
 	n.Right = nright
@@ -423,12 +398,10 @@
 }
 
 func saveorignode(n *Node) {
-	var norig *Node
-
 	if n.Orig != nil {
 		return
 	}
-	norig = Nod(int(n.Op), nil, nil)
+	norig := Nod(int(n.Op), nil, nil)
 	*norig = *n
 	n.Orig = norig
 }
@@ -447,10 +420,6 @@
 }
 
 func algtype1(t *Type, bad **Type) int {
-	var a int
-	var ret int
-	var t1 *Type
-
 	if bad != nil {
 		*bad = nil
 	}
@@ -523,7 +492,7 @@
 			return ANOEQ
 		}
 
-		a = algtype1(t.Type, bad)
+		a := algtype1(t.Type, bad)
 		if a == ANOEQ || a == AMEM {
 			if a == ANOEQ && bad != nil {
 				*bad = t
@@ -539,8 +508,9 @@
 			return algtype1(t.Type.Type, bad)
 		}
 
-		ret = AMEM
-		for t1 = t.Type; t1 != nil; t1 = t1.Down {
+		ret := AMEM
+		var a int
+		for t1 := t.Type; t1 != nil; t1 = t1.Down {
 			// All fields must be comparable.
 			a = algtype1(t1.Type, bad)
 
@@ -564,9 +534,7 @@
 }
 
 func algtype(t *Type) int {
-	var a int
-
-	a = algtype1(t, nil)
+	a := algtype1(t, nil)
 	if a == AMEM || a == ANOEQ {
 		if Isslice(t) {
 			return ASLICE
@@ -596,13 +564,10 @@
 }
 
 func maptype(key *Type, val *Type) *Type {
-	var t *Type
-	var bad *Type
-	var atype int
-	var mtype int
-
 	if key != nil {
-		atype = algtype1(key, &bad)
+		var bad *Type
+		atype := algtype1(key, &bad)
+		var mtype int
 		if bad == nil {
 			mtype = int(key.Etype)
 		} else {
@@ -631,16 +596,14 @@
 		}
 	}
 
-	t = typ(TMAP)
+	t := typ(TMAP)
 	t.Down = key
 	t.Type = val
 	return t
 }
 
 func typ(et int) *Type {
-	var t *Type
-
-	t = new(Type)
+	t := new(Type)
 	t.Etype = uint8(et)
 	t.Width = BADWIDTH
 	t.Lineno = int(lineno)
@@ -659,12 +622,8 @@
 }
 
 func (x methcmp) Less(i, j int) bool {
-	var a *Type
-	var b *Type
-	var k int
-
-	a = x[i]
-	b = x[j]
+	a := x[i]
+	b := x[j]
 	if a.Sym == nil && b.Sym == nil {
 		return false
 	}
@@ -674,12 +633,12 @@
 	if b.Sym == nil {
 		return 1 < 0
 	}
-	k = stringsCompare(a.Sym.Name, b.Sym.Name)
+	k := stringsCompare(a.Sym.Name, b.Sym.Name)
 	if k != 0 {
 		return k < 0
 	}
 	if !exportname(a.Sym.Name) {
-		k = stringsCompare(a.Sym.Pkg.Path.S, b.Sym.Pkg.Path.S)
+		k := stringsCompare(a.Sym.Pkg.Path.S, b.Sym.Pkg.Path.S)
 		if k != 0 {
 			return k < 0
 		}
@@ -689,20 +648,17 @@
 }
 
 func sortinter(t *Type) *Type {
-	var f *Type
-	var i int
-	var a []*Type
-
 	if t.Type == nil || t.Type.Down == nil {
 		return t
 	}
 
-	i = 0
-	for f = t.Type; f != nil; f = f.Down {
+	i := 0
+	for f := t.Type; f != nil; f = f.Down {
 		i++
 	}
-	a = make([]*Type, i)
+	a := make([]*Type, i)
 	i = 0
+	var f *Type
 	for f = t.Type; f != nil; f = f.Down {
 		a[i] = f
 		i++
@@ -723,9 +679,7 @@
 }
 
 func Nodintconst(v int64) *Node {
-	var c *Node
-
-	c = Nod(OLITERAL, nil, nil)
+	c := Nod(OLITERAL, nil, nil)
 	c.Addable = 1
 	c.Val.U.Xval = new(Mpint)
 	Mpmovecfix(c.Val.U.Xval, v)
@@ -736,9 +690,7 @@
 }
 
 func nodfltconst(v *Mpflt) *Node {
-	var c *Node
-
-	c = Nod(OLITERAL, nil, nil)
+	c := Nod(OLITERAL, nil, nil)
 	c.Addable = 1
 	c.Val.U.Fval = new(Mpflt)
 	mpmovefltflt(c.Val.U.Fval, v)
@@ -764,18 +716,14 @@
 }
 
 func nodnil() *Node {
-	var c *Node
-
-	c = Nodintconst(0)
+	c := Nodintconst(0)
 	c.Val.Ctype = CTNIL
 	c.Type = Types[TNIL]
 	return c
 }
 
 func Nodbool(b bool) *Node {
-	var c *Node
-
-	c = Nodintconst(0)
+	c := Nodintconst(0)
 	c.Val.Ctype = CTBOOL
 	c.Val.U.Bval = int16(bool2int(b))
 	c.Type = idealbool
@@ -783,10 +731,7 @@
 }
 
 func aindex(b *Node, t *Type) *Type {
-	var r *Type
-	var bound int64
-
-	bound = -1 // open bound
+	bound := int64(-1) // open bound
 	typecheck(&b, Erv)
 	if b != nil {
 		switch consttype(b) {
@@ -803,7 +748,7 @@
 	}
 
 	// fixed array
-	r = typ(TARRAY)
+	r := typ(TARRAY)
 
 	r.Type = t
 	r.Bound = bound
@@ -811,12 +756,11 @@
 }
 
 func treecopy(n *Node) *Node {
-	var m *Node
-
 	if n == nil {
 		return nil
 	}
 
+	var m *Node
 	switch n.Op {
 	default:
 		m = Nod(OXXX, nil, nil)
@@ -1023,8 +967,6 @@
 }
 
 func eqtype1(t1 *Type, t2 *Type, assumed_equal *TypePairList) bool {
-	var l TypePairList
-
 	if t1 == t2 {
 		return true
 	}
@@ -1053,6 +995,7 @@
 	if onlist(assumed_equal, t1, t2) {
 		return true
 	}
+	var l TypePairList
 	l.next = assumed_equal
 	l.t1 = t1
 	l.t2 = t2
@@ -1159,10 +1102,6 @@
 // If so, return op code to use in conversion.
 // If not, return 0.
 func assignop(src *Type, dst *Type, why *string) int {
-	var missing *Type
-	var have *Type
-	var ptr int
-
 	if why != nil {
 		*why = ""
 	}
@@ -1197,6 +1136,9 @@
 
 	// 3. dst is an interface type and src implements dst.
 	if dst.Etype == TINTER && src.Etype != TNIL {
+		var missing *Type
+		var ptr int
+		var have *Type
 		if implements(src, dst, &missing, &have, &ptr) {
 			return OCONVIFACE
 		}
@@ -1233,6 +1175,9 @@
 	}
 
 	if src.Etype == TINTER && dst.Etype != TBLANK {
+		var have *Type
+		var ptr int
+		var missing *Type
 		if why != nil && implements(dst, src, &missing, &have, &ptr) {
 			*why = ": need type assertion"
 		}
@@ -1281,8 +1226,6 @@
 // If so, return op code to use in conversion (maybe OCONVNOP).
 // If not, return 0.
 func convertop(src *Type, dst *Type, why *string) int {
-	var op int
-
 	if why != nil {
 		*why = ""
 	}
@@ -1295,7 +1238,7 @@
 	}
 
 	// 1. src can be assigned to dst.
-	op = assignop(src, dst, why)
+	op := assignop(src, dst, why)
 	if op != 0 {
 		return op
 	}
@@ -1381,11 +1324,6 @@
 
 // Convert node n for assignment to type t.
 func assignconv(n *Node, t *Type, context string) *Node {
-	var op int
-	var r *Node
-	var old *Node
-	var why string
-
 	if n == nil || n.Type == nil || n.Type.Broke != 0 {
 		return n
 	}
@@ -1394,7 +1332,7 @@
 		Yyerror("use of untyped nil")
 	}
 
-	old = n
+	old := n
 	old.Diag++ // silence errors about n; we'll issue one below
 	defaultlit(&n, t)
 	old.Diag--
@@ -1406,7 +1344,7 @@
 	// if the next step is non-bool (like interface{}).
 	if n.Type == idealbool && t.Etype != TBOOL {
 		if n.Op == ONAME || n.Op == OLITERAL {
-			r = Nod(OCONVNOP, n, nil)
+			r := Nod(OCONVNOP, n, nil)
 			r.Type = Types[TBOOL]
 			r.Typecheck = 1
 			r.Implicit = 1
@@ -1418,13 +1356,14 @@
 		return n
 	}
 
-	op = assignop(n.Type, t, &why)
+	var why string
+	op := assignop(n.Type, t, &why)
 	if op == 0 {
 		Yyerror("cannot use %v as type %v in %s%s", Nconv(n, obj.FmtLong), Tconv(t, 0), context, why)
 		op = OCONV
 	}
 
-	r = Nod(op, n, nil)
+	r := Nod(op, n, nil)
 	r.Type = t
 	r.Typecheck = 1
 	r.Implicit = 1
@@ -1517,11 +1456,8 @@
  * Is a conversion between t1 and t2 a no-op?
  */
 func Noconv(t1 *Type, t2 *Type) bool {
-	var e1 int
-	var e2 int
-
-	e1 = int(Simtype[t1.Etype])
-	e2 = int(Simtype[t2.Etype])
+	e1 := int(Simtype[t1.Etype])
+	e2 := int(Simtype[t2.Etype])
 
 	switch e1 {
 	case TINT8,
@@ -1560,12 +1496,10 @@
 }
 
 func shallow(t *Type) *Type {
-	var nt *Type
-
 	if t == nil {
 		return nil
 	}
-	nt = typ(0)
+	nt := typ(0)
 	*nt = *t
 	if t.Orig == t {
 		nt.Orig = nt
@@ -1574,13 +1508,11 @@
 }
 
 func deep(t *Type) *Type {
-	var nt *Type
-	var xt *Type
-
 	if t == nil {
 		return nil
 	}
 
+	var nt *Type
 	switch t.Etype {
 	default:
 		nt = t // share from here down
@@ -1610,7 +1542,7 @@
 	case TSTRUCT:
 		nt = shallow(t)
 		nt.Type = shallow(t.Type)
-		xt = nt.Type
+		xt := nt.Type
 
 		for t = t.Type; t != nil; t = t.Down {
 			xt.Type = deep(t.Type)
@@ -1623,10 +1555,7 @@
 }
 
 func syslook(name string, copy int) *Node {
-	var s *Sym
-	var n *Node
-
-	s = Pkglookup(name, Runtimepkg)
+	s := Pkglookup(name, Runtimepkg)
 	if s == nil || s.Def == nil {
 		Fatal("syslook: can't find runtime.%s", name)
 	}
@@ -1635,7 +1564,7 @@
 		return s.Def
 	}
 
-	n = Nod(0, nil, nil)
+	n := Nod(0, nil, nil)
 	*n = *s.Def
 	n.Type = deep(s.Def.Type)
 
@@ -1656,7 +1585,6 @@
  */
 func typehash(t *Type) uint32 {
 	var p string
-	var d MD5
 
 	if t.Thistuple != 0 {
 		// hide method receiver from Tpretty
@@ -1669,6 +1597,7 @@
 	}
 
 	//print("typehash: %s\n", p);
+	var d MD5
 	md5reset(&d)
 
 	md5write(&d, []byte(p), len(p))
@@ -1677,12 +1606,10 @@
 }
 
 func Ptrto(t *Type) *Type {
-	var t1 *Type
-
 	if Tptr == 0 {
 		Fatal("ptrto: no tptr")
 	}
-	t1 = typ(Tptr)
+	t1 := typ(Tptr)
 	t1.Type = t
 	t1.Width = int64(Widthptr)
 	t1.Align = uint8(Widthptr)
@@ -1691,8 +1618,6 @@
 
 func frame(context int) {
 	var l *NodeList
-	var n *Node
-	var w int64
 
 	if context != 0 {
 		fmt.Printf("--- external frame ---\n")
@@ -1704,6 +1629,8 @@
 		return
 	}
 
+	var n *Node
+	var w int64
 	for ; l != nil; l = l.Next {
 		n = l.N
 		w = -1
@@ -1727,13 +1654,12 @@
  * hardest side first to minimize registers.
  */
 func ullmancalc(n *Node) {
-	var ul int
-	var ur int
-
 	if n == nil {
 		return
 	}
 
+	var ul int
+	var ur int
 	if n.Ninit != nil {
 		ul = UINF
 		goto out
@@ -1788,10 +1714,7 @@
 }
 
 func badtype(o int, tl *Type, tr *Type) {
-	var fmt_ string
-	var s string
-
-	fmt_ = ""
+	fmt_ := ""
 	if tl != nil {
 		fmt_ += fmt.Sprintf("\n\t%v", Tconv(tl, 0))
 	}
@@ -1808,7 +1731,7 @@
 		}
 	}
 
-	s = fmt_
+	s := fmt_
 	Yyerror("illegal types for operand: %v%s", Oconv(int(o), 0), s)
 }
 
@@ -1816,10 +1739,9 @@
  * iterator to walk a structure declaration
  */
 func Structfirst(s *Iter, nn **Type) *Type {
-	var n *Type
 	var t *Type
 
-	n = *nn
+	n := *nn
 	if n == nil {
 		goto bad
 	}
@@ -1854,11 +1776,8 @@
 }
 
 func structnext(s *Iter) *Type {
-	var n *Type
-	var t *Type
-
-	n = s.T
-	t = n.Down
+	n := s.T
+	t := n.Down
 	if t == nil {
 		goto rnil
 	}
@@ -1907,9 +1826,7 @@
 }
 
 func funcnext(s *Iter) *Type {
-	var fp *Type
-
-	fp = structnext(s)
+	fp := structnext(s)
 	if fp == nil && s.Done == 0 {
 		s.Done = 1
 		fp = Structfirst(s, getinarg(s.Tfunc))
@@ -2004,10 +1921,6 @@
  * result is assignable if n is.
  */
 func safeexpr(n *Node, init **NodeList) *Node {
-	var l *Node
-	var r *Node
-	var a *Node
-
 	if n == nil {
 		return nil
 	}
@@ -2024,11 +1937,11 @@
 		return n
 
 	case ODOT:
-		l = safeexpr(n.Left, init)
+		l := safeexpr(n.Left, init)
 		if l == n.Left {
 			return n
 		}
-		r = Nod(OXXX, nil, nil)
+		r := Nod(OXXX, nil, nil)
 		*r = *n
 		r.Left = l
 		typecheck(&r, Erv)
@@ -2037,11 +1950,11 @@
 
 	case ODOTPTR,
 		OIND:
-		l = safeexpr(n.Left, init)
+		l := safeexpr(n.Left, init)
 		if l == n.Left {
 			return n
 		}
-		a = Nod(OXXX, nil, nil)
+		a := Nod(OXXX, nil, nil)
 		*a = *n
 		a.Left = l
 		walkexpr(&a, init)
@@ -2049,12 +1962,12 @@
 
 	case OINDEX,
 		OINDEXMAP:
-		l = safeexpr(n.Left, init)
-		r = safeexpr(n.Right, init)
+		l := safeexpr(n.Left, init)
+		r := safeexpr(n.Right, init)
 		if l == n.Left && r == n.Right {
 			return n
 		}
-		a = Nod(OXXX, nil, nil)
+		a := Nod(OXXX, nil, nil)
 		*a = *n
 		a.Left = l
 		a.Right = r
@@ -2070,11 +1983,8 @@
 }
 
 func copyexpr(n *Node, t *Type, init **NodeList) *Node {
-	var a *Node
-	var l *Node
-
-	l = temp(t)
-	a = Nod(OAS, l, n)
+	l := temp(t)
+	a := Nod(OAS, l, n)
 	typecheck(&a, Etop)
 	walkexpr(&a, init)
 	*init = list(*init, a)
@@ -2109,10 +2019,8 @@
 }
 
 func Setmaxarg(t *Type, extra int32) {
-	var w int64
-
 	dowidth(t)
-	w = t.Argwid
+	w := t.Argwid
 	if w >= Thearch.MAXWIDTH {
 		Fatal("bad argwid %v", Tconv(t, 0))
 	}
@@ -2138,18 +2046,14 @@
 // return count of fields+methods
 // found with a given name
 func lookdot0(s *Sym, t *Type, save **Type, ignorecase int) int {
-	var f *Type
-	var u *Type
-	var c int
-
-	u = t
+	u := t
 	if Isptr[u.Etype] != 0 {
 		u = u.Type
 	}
 
-	c = 0
+	c := 0
 	if u.Etype == TSTRUCT || u.Etype == TINTER {
-		for f = u.Type; f != nil; f = f.Down {
+		for f := u.Type; f != nil; f = f.Down {
 			if f.Sym == s || (ignorecase != 0 && f.Type.Etype == TFUNC && f.Type.Thistuple > 0 && strings.EqualFold(f.Sym.Name, s.Name)) {
 				if save != nil {
 					*save = f
@@ -2161,7 +2065,7 @@
 
 	u = methtype(t, 0)
 	if u != nil {
-		for f = u.Method; f != nil; f = f.Down {
+		for f := u.Method; f != nil; f = f.Down {
 			if f.Embedded == 0 && (f.Sym == s || (ignorecase != 0 && strings.EqualFold(f.Sym.Name, s.Name))) {
 				if save != nil {
 					*save = f
@@ -2180,16 +2084,14 @@
 // answer is in dotlist array and
 // count of number of ways is returned.
 func adddot1(s *Sym, t *Type, d int, save **Type, ignorecase int) int {
-	var f *Type
-	var u *Type
-	var c int
-	var a int
-
 	if t.Trecur != 0 {
 		return 0
 	}
 	t.Trecur = 1
 
+	var c int
+	var u *Type
+	var a int
 	if d == 0 {
 		c = lookdot0(s, t, save, ignorecase)
 		goto out
@@ -2205,7 +2107,7 @@
 	}
 
 	d--
-	for f = u.Type; f != nil; f = f.Down {
+	for f := u.Type; f != nil; f = f.Down {
 		if f.Embedded == 0 {
 			continue
 		}
@@ -2229,14 +2131,13 @@
 // will give shortest unique addressing.
 // modify the tree with missing type names.
 func adddot(n *Node) *Node {
-	var t *Type
 	var s *Sym
 	var c int
 	var d int
 
 	typecheck(&n.Left, Etype|Erv)
 	n.Diag |= n.Left.Diag
-	t = n.Left.Type
+	t := n.Left.Type
 	if t == nil {
 		goto ret
 	}
@@ -2270,7 +2171,7 @@
 	}
 
 	// rebuild elided dots
-	for c = d - 1; c >= 0; c-- {
+	for c := d - 1; c >= 0; c-- {
 		n.Left = Nod(ODOT, n.Left, newname(dotlist[c].field.Sym))
 	}
 
@@ -2298,18 +2199,15 @@
 var slist *Symlink
 
 func expand0(t *Type, followptr int) {
-	var f *Type
-	var u *Type
-	var sl *Symlink
-
-	u = t
+	u := t
 	if Isptr[u.Etype] != 0 {
 		followptr = 1
 		u = u.Type
 	}
 
 	if u.Etype == TINTER {
-		for f = u.Type; f != nil; f = f.Down {
+		var sl *Symlink
+		for f := u.Type; f != nil; f = f.Down {
 			if f.Sym.Flags&SymUniq != 0 {
 				continue
 			}
@@ -2326,7 +2224,8 @@
 
 	u = methtype(t, 0)
 	if u != nil {
-		for f = u.Method; f != nil; f = f.Down {
+		var sl *Symlink
+		for f := u.Method; f != nil; f = f.Down {
 			if f.Sym.Flags&SymUniq != 0 {
 				continue
 			}
@@ -2341,9 +2240,6 @@
 }
 
 func expand1(t *Type, d int, followptr int) {
-	var f *Type
-	var u *Type
-
 	if t.Trecur != 0 {
 		return
 	}
@@ -2356,7 +2252,7 @@
 		expand0(t, followptr)
 	}
 
-	u = t
+	u := t
 	if Isptr[u.Etype] != 0 {
 		followptr = 1
 		u = u.Type
@@ -2366,7 +2262,7 @@
 		goto out
 	}
 
-	for f = u.Type; f != nil; f = f.Down {
+	for f := u.Type; f != nil; f = f.Down {
 		if f.Embedded == 0 {
 			continue
 		}
@@ -2381,17 +2277,13 @@
 }
 
 func expandmeth(t *Type) {
-	var sl *Symlink
-	var f *Type
-	var c int
-	var d int
-
 	if t == nil || t.Xmethod != nil {
 		return
 	}
 
 	// mark top-level method symbols
 	// so that expand1 doesn't consider them.
+	var f *Type
 	for f = t.Method; f != nil; f = f.Down {
 		f.Sym.Flags |= SymUniq
 	}
@@ -2402,7 +2294,9 @@
 	expand1(t, len(dotlist)-1, 0)
 
 	// check each method to be uniquely reachable
-	for sl = slist; sl != nil; sl = sl.link {
+	var c int
+	var d int
+	for sl := slist; sl != nil; sl = sl.link {
 		sl.field.Sym.Flags &^= SymUniq
 		for d = 0; d < len(dotlist); d++ {
 			c = adddot1(sl.field.Sym, t, d, &f, 0)
@@ -2426,7 +2320,7 @@
 	}
 
 	t.Xmethod = t.Method
-	for sl = slist; sl != nil; sl = sl.link {
+	for sl := slist; sl != nil; sl = sl.link {
 		if sl.good != 0 {
 			// add it to the base type method list
 			f = typ(TFIELD)
@@ -2449,14 +2343,11 @@
 	var savet Iter
 	var a *Node
 	var n *Node
-	var args *NodeList
-	var t *Type
 	var buf string
-	var gen int
 
-	args = nil
-	gen = 0
-	for t = Structfirst(&savet, tl); t != nil; t = structnext(&savet) {
+	args := (*NodeList)(nil)
+	gen := 0
+	for t := Structfirst(&savet, tl); t != nil; t = structnext(&savet) {
 		n = nil
 		if mustname != 0 && (t.Sym == nil || t.Sym.Name == "_") {
 			// invent a name so that we can refer to it in the trampoline
@@ -2505,23 +2396,6 @@
 var genwrapper_linehistdone int = 0
 
 func genwrapper(rcvr *Type, method *Type, newnam *Sym, iface int) {
-	var this *Node
-	var fn *Node
-	var call *Node
-	var n *Node
-	var t *Node
-	var pad *Node
-	var dot *Node
-	var as *Node
-	var l *NodeList
-	var args *NodeList
-	var in *NodeList
-	var out *NodeList
-	var tpad *Type
-	var methodrcvr *Type
-	var isddd int
-	var v Val
-
 	if false && Debug['r'] != 0 {
 		fmt.Printf("genwrapper rcvrtype=%v method=%v newnam=%v\n", Tconv(rcvr, 0), Tconv(method, 0), Sconv(newnam, 0))
 	}
@@ -2538,31 +2412,31 @@
 	dclcontext = PEXTERN
 	markdcl()
 
-	this = Nod(ODCLFIELD, newname(Lookup(".this")), typenod(rcvr))
+	this := Nod(ODCLFIELD, newname(Lookup(".this")), typenod(rcvr))
 	this.Left.Ntype = this.Right
-	in = structargs(getinarg(method.Type), 1)
-	out = structargs(Getoutarg(method.Type), 0)
+	in := structargs(getinarg(method.Type), 1)
+	out := structargs(Getoutarg(method.Type), 0)
 
-	t = Nod(OTFUNC, nil, nil)
-	l = list1(this)
+	t := Nod(OTFUNC, nil, nil)
+	l := list1(this)
 	if iface != 0 && rcvr.Width < Types[Tptr].Width {
 		// Building method for interface table and receiver
 		// is smaller than the single pointer-sized word
 		// that the interface call will pass in.
 		// Add a dummy padding argument after the
 		// receiver to make up the difference.
-		tpad = typ(TARRAY)
+		tpad := typ(TARRAY)
 
 		tpad.Type = Types[TUINT8]
 		tpad.Bound = Types[Tptr].Width - rcvr.Width
-		pad = Nod(ODCLFIELD, newname(Lookup(".pad")), typenod(tpad))
+		pad := Nod(ODCLFIELD, newname(Lookup(".pad")), typenod(tpad))
 		l = list(l, pad)
 	}
 
 	t.List = concat(l, in)
 	t.Rlist = out
 
-	fn = Nod(ODCLFUNC, nil, nil)
+	fn := Nod(ODCLFUNC, nil, nil)
 	fn.Nname = newname(newnam)
 	fn.Nname.Defn = fn
 	fn.Nname.Ntype = t
@@ -2570,27 +2444,28 @@
 	funchdr(fn)
 
 	// arg list
-	args = nil
+	args := (*NodeList)(nil)
 
-	isddd = 0
-	for l = in; l != nil; l = l.Next {
+	isddd := 0
+	for l := in; l != nil; l = l.Next {
 		args = list(args, l.N.Left)
 		isddd = int(l.N.Left.Isddd)
 	}
 
-	methodrcvr = getthisx(method.Type).Type.Type
+	methodrcvr := getthisx(method.Type).Type.Type
 
 	// generate nil pointer check for better error
 	if Isptr[rcvr.Etype] != 0 && rcvr.Type == methodrcvr {
 		// generating wrapper from *T to T.
-		n = Nod(OIF, nil, nil)
+		n := Nod(OIF, nil, nil)
 
 		n.Ntest = Nod(OEQ, this.Left, nodnil())
 
 		// these strings are already in the reflect tables,
 		// so no space cost to use them here.
-		l = nil
+		l := (*NodeList)(nil)
 
+		var v Val
 		v.Ctype = CTSTR
 		v.U.Sval = newstrlit(rcvr.Type.Sym.Pkg.Name) // package name
 		l = list(l, nodlit(v))
@@ -2598,13 +2473,13 @@
 		l = list(l, nodlit(v))
 		v.U.Sval = newstrlit(method.Sym.Name)
 		l = list(l, nodlit(v)) // method name
-		call = Nod(OCALL, syslook("panicwrap", 0), nil)
+		call := Nod(OCALL, syslook("panicwrap", 0), nil)
 		call.List = l
 		n.Nbody = list1(call)
 		fn.Nbody = list(fn.Nbody, n)
 	}
 
-	dot = adddot(Nod(OXDOT, this.Left, newname(method.Sym)))
+	dot := adddot(Nod(OXDOT, this.Left, newname(method.Sym)))
 
 	// generate call
 	if flag_race == 0 && Isptr[rcvr.Etype] != 0 && Isptr[methodrcvr.Etype] != 0 && method.Embedded != 0 && !isifacemethod(method.Type) {
@@ -2613,19 +2488,19 @@
 		if Isptr[dotlist[0].field.Type.Etype] == 0 {
 			dot = Nod(OADDR, dot, nil)
 		}
-		as = Nod(OAS, this.Left, Nod(OCONVNOP, dot, nil))
+		as := Nod(OAS, this.Left, Nod(OCONVNOP, dot, nil))
 		as.Right.Type = rcvr
 		fn.Nbody = list(fn.Nbody, as)
-		n = Nod(ORETJMP, nil, nil)
+		n := Nod(ORETJMP, nil, nil)
 		n.Left = newname(methodsym(method.Sym, methodrcvr, 0))
 		fn.Nbody = list(fn.Nbody, n)
 	} else {
 		fn.Wrapper = 1 // ignore frame for panic+recover matching
-		call = Nod(OCALL, dot, nil)
+		call := Nod(OCALL, dot, nil)
 		call.List = args
 		call.Isddd = uint8(isddd)
 		if method.Type.Outtuple > 0 {
-			n = Nod(ORETURN, nil, nil)
+			n := Nod(ORETURN, nil, nil)
 			n.List = list1(call)
 			call = n
 		}
@@ -2662,15 +2537,11 @@
 }
 
 func hashmem(t *Type) *Node {
-	var tfn *Node
-	var n *Node
-	var sym *Sym
+	sym := Pkglookup("memhash", Runtimepkg)
 
-	sym = Pkglookup("memhash", Runtimepkg)
-
-	n = newname(sym)
+	n := newname(sym)
 	n.Class = PFUNC
-	tfn = Nod(OTFUNC, nil, nil)
+	tfn := Nod(OTFUNC, nil, nil)
 	tfn.List = list(tfn.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
 	tfn.List = list(tfn.List, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
 	tfn.List = list(tfn.List, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
@@ -2681,12 +2552,9 @@
 }
 
 func hashfor(t *Type) *Node {
-	var a int
 	var sym *Sym
-	var tfn *Node
-	var n *Node
 
-	a = algtype1(t, nil)
+	a := algtype1(t, nil)
 	switch a {
 	case AMEM:
 		Fatal("hashfor with AMEM type")
@@ -2716,9 +2584,9 @@
 		sym = typesymprefix(".hash", t)
 	}
 
-	n = newname(sym)
+	n := newname(sym)
 	n.Class = PFUNC
-	tfn = Nod(OTFUNC, nil, nil)
+	tfn := Nod(OTFUNC, nil, nil)
 	tfn.List = list(tfn.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
 	tfn.List = list(tfn.List, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
 	tfn.Rlist = list(tfn.Rlist, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
@@ -2731,24 +2599,6 @@
  * Generate a helper function to compute the hash of a value of type t.
  */
 func genhash(sym *Sym, t *Type) {
-	var n *Node
-	var fn *Node
-	var np *Node
-	var nh *Node
-	var ni *Node
-	var call *Node
-	var nx *Node
-	var na *Node
-	var tfn *Node
-	var r *Node
-	var hashel *Node
-	var first *Type
-	var t1 *Type
-	var old_safemode int
-	var size int64
-	var mul int64
-	var offend int64
-
 	if Debug['r'] != 0 {
 		fmt.Printf("genhash %v %v\n", Sconv(sym, 0), Tconv(t, 0))
 	}
@@ -2758,19 +2608,19 @@
 	markdcl()
 
 	// func sym(p *T, h uintptr) uintptr
-	fn = Nod(ODCLFUNC, nil, nil)
+	fn := Nod(ODCLFUNC, nil, nil)
 
 	fn.Nname = newname(sym)
 	fn.Nname.Class = PFUNC
-	tfn = Nod(OTFUNC, nil, nil)
+	tfn := Nod(OTFUNC, nil, nil)
 	fn.Nname.Ntype = tfn
 
-	n = Nod(ODCLFIELD, newname(Lookup("p")), typenod(Ptrto(t)))
+	n := Nod(ODCLFIELD, newname(Lookup("p")), typenod(Ptrto(t)))
 	tfn.List = list(tfn.List, n)
-	np = n.Left
+	np := n.Left
 	n = Nod(ODCLFIELD, newname(Lookup("h")), typenod(Types[TUINTPTR]))
 	tfn.List = list(tfn.List, n)
-	nh = n.Left
+	nh := n.Left
 	n = Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])) // return value
 	tfn.Rlist = list(tfn.Rlist, n)
 
@@ -2792,10 +2642,10 @@
 		// An array of pure memory would be handled by the
 		// standard algorithm, so the element type must not be
 		// pure memory.
-		hashel = hashfor(t.Type)
+		hashel := hashfor(t.Type)
 
-		n = Nod(ORANGE, nil, Nod(OIND, np, nil))
-		ni = newname(Lookup("i"))
+		n := Nod(ORANGE, nil, Nod(OIND, np, nil))
+		ni := newname(Lookup("i"))
 		ni.Type = Types[TINT]
 		n.List = list1(ni)
 		n.Colas = 1
@@ -2809,6 +2659,7 @@
 
 		// h *= mul
 		// Same multipliers as in runtime.memhash.
+		var mul int64
 		if Widthptr == 4 {
 			mul = 3267000013
 		} else {
@@ -2817,11 +2668,11 @@
 		n.Nbody = list(n.Nbody, Nod(OAS, nh, Nod(OMUL, nh, Nodintconst(mul))))
 
 		// h = hashel(&p[i], h)
-		call = Nod(OCALL, hashel, nil)
+		call := Nod(OCALL, hashel, nil)
 
-		nx = Nod(OINDEX, np, ni)
+		nx := Nod(OINDEX, np, ni)
 		nx.Bounded = true
-		na = Nod(OADDR, nx, nil)
+		na := Nod(OADDR, nx, nil)
 		na.Etype = 1 // no escape to heap
 		call.List = list(call.List, na)
 		call.List = list(call.List, nh)
@@ -2832,10 +2683,15 @@
 		// Walk the struct using memhash for runs of AMEM
 	// and calling specific hash functions for the others.
 	case TSTRUCT:
-		first = nil
+		first := (*Type)(nil)
 
-		offend = 0
-		for t1 = t.Type; ; t1 = t1.Down {
+		offend := int64(0)
+		var size int64
+		var call *Node
+		var nx *Node
+		var na *Node
+		var hashel *Node
+		for t1 := t.Type; ; t1 = t1.Down {
 			if t1 != nil && algtype1(t1.Type, nil) == AMEM && !isblanksym(t1.Sym) {
 				offend = t1.Width + t1.Type.Width
 				if first == nil {
@@ -2906,7 +2762,7 @@
 		}
 	}
 
-	r = Nod(ORETURN, nil, nil)
+	r := Nod(ORETURN, nil, nil)
 	r.List = list(r.List, nh)
 	fn.Nbody = list(fn.Nbody, r)
 
@@ -2926,7 +2782,7 @@
 	// In this case it can happen if we need to generate an ==
 	// for a struct containing a reflect.Value, which itself has
 	// an unexported field of type unsafe.Pointer.
-	old_safemode = safemode
+	old_safemode := safemode
 
 	safemode = 0
 	funccompile(fn)
@@ -2936,23 +2792,17 @@
 // Return node for
 //	if p.field != q.field { return false }
 func eqfield(p *Node, q *Node, field *Node) *Node {
-	var nif *Node
-	var nx *Node
-	var ny *Node
-	var r *Node
-
-	nx = Nod(OXDOT, p, field)
-	ny = Nod(OXDOT, q, field)
-	nif = Nod(OIF, nil, nil)
+	nx := Nod(OXDOT, p, field)
+	ny := Nod(OXDOT, q, field)
+	nif := Nod(OIF, nil, nil)
 	nif.Ntest = Nod(ONE, nx, ny)
-	r = Nod(ORETURN, nil, nil)
+	r := Nod(ORETURN, nil, nil)
 	r.List = list(r.List, Nodbool(false))
 	nif.Nbody = list(nif.Nbody, r)
 	return nif
 }
 
 func eqmemfunc(size int64, type_ *Type, needsize *int) *Node {
-	var buf string
 	var fn *Node
 
 	switch size {
@@ -2965,7 +2815,7 @@
 		4,
 		8,
 		16:
-		buf = fmt.Sprintf("memequal%d", int(size)*8)
+		buf := fmt.Sprintf("memequal%d", int(size)*8)
 		fn = syslook(buf, 1)
 		*needsize = 0
 	}
@@ -2978,31 +2828,26 @@
 // Return node for
 //	if !memequal(&p.field, &q.field [, size]) { return false }
 func eqmem(p *Node, q *Node, field *Node, size int64) *Node {
-	var nif *Node
-	var nx *Node
-	var ny *Node
-	var call *Node
-	var r *Node
 	var needsize int
 
-	nx = Nod(OADDR, Nod(OXDOT, p, field), nil)
+	nx := Nod(OADDR, Nod(OXDOT, p, field), nil)
 	nx.Etype = 1 // does not escape
-	ny = Nod(OADDR, Nod(OXDOT, q, field), nil)
+	ny := Nod(OADDR, Nod(OXDOT, q, field), nil)
 	ny.Etype = 1 // does not escape
 	typecheck(&nx, Erv)
 	typecheck(&ny, Erv)
 
-	call = Nod(OCALL, eqmemfunc(size, nx.Type.Type, &needsize), nil)
+	call := Nod(OCALL, eqmemfunc(size, nx.Type.Type, &needsize), nil)
 	call.List = list(call.List, nx)
 	call.List = list(call.List, ny)
 	if needsize != 0 {
 		call.List = list(call.List, Nodintconst(size))
 	}
 
-	nif = Nod(OIF, nil, nil)
+	nif := Nod(OIF, nil, nil)
 	nif.Ninit = list(nif.Ninit, call)
 	nif.Ntest = Nod(ONOT, call, nil)
-	r = Nod(ORETURN, nil, nil)
+	r := Nod(ORETURN, nil, nil)
 	r.List = list(r.List, Nodbool(false))
 	nif.Nbody = list(nif.Nbody, r)
 	return nif
@@ -3012,23 +2857,6 @@
  * Generate a helper function to check equality of two values of type t.
  */
 func geneq(sym *Sym, t *Type) {
-	var n *Node
-	var fn *Node
-	var np *Node
-	var nq *Node
-	var tfn *Node
-	var nif *Node
-	var ni *Node
-	var nx *Node
-	var ny *Node
-	var nrange *Node
-	var r *Node
-	var t1 *Type
-	var first *Type
-	var old_safemode int
-	var size int64
-	var offend int64
-
 	if Debug['r'] != 0 {
 		fmt.Printf("geneq %v %v\n", Sconv(sym, 0), Tconv(t, 0))
 	}
@@ -3038,19 +2866,19 @@
 	markdcl()
 
 	// func sym(p, q *T) bool
-	fn = Nod(ODCLFUNC, nil, nil)
+	fn := Nod(ODCLFUNC, nil, nil)
 
 	fn.Nname = newname(sym)
 	fn.Nname.Class = PFUNC
-	tfn = Nod(OTFUNC, nil, nil)
+	tfn := Nod(OTFUNC, nil, nil)
 	fn.Nname.Ntype = tfn
 
-	n = Nod(ODCLFIELD, newname(Lookup("p")), typenod(Ptrto(t)))
+	n := Nod(ODCLFIELD, newname(Lookup("p")), typenod(Ptrto(t)))
 	tfn.List = list(tfn.List, n)
-	np = n.Left
+	np := n.Left
 	n = Nod(ODCLFIELD, newname(Lookup("q")), typenod(Ptrto(t)))
 	tfn.List = list(tfn.List, n)
-	nq = n.Left
+	nq := n.Left
 	n = Nod(ODCLFIELD, nil, typenod(Types[TBOOL]))
 	tfn.Rlist = list(tfn.Rlist, n)
 
@@ -3073,9 +2901,9 @@
 		// pure memory.  Even if we unrolled the range loop,
 		// each iteration would be a function call, so don't bother
 		// unrolling.
-		nrange = Nod(ORANGE, nil, Nod(OIND, np, nil))
+		nrange := Nod(ORANGE, nil, Nod(OIND, np, nil))
 
-		ni = newname(Lookup("i"))
+		ni := newname(Lookup("i"))
 		ni.Type = Types[TINT]
 		nrange.List = list1(ni)
 		nrange.Colas = 1
@@ -3083,15 +2911,15 @@
 		ni = nrange.List.N
 
 		// if p[i] != q[i] { return false }
-		nx = Nod(OINDEX, np, ni)
+		nx := Nod(OINDEX, np, ni)
 
 		nx.Bounded = true
-		ny = Nod(OINDEX, nq, ni)
+		ny := Nod(OINDEX, nq, ni)
 		ny.Bounded = true
 
-		nif = Nod(OIF, nil, nil)
+		nif := Nod(OIF, nil, nil)
 		nif.Ntest = Nod(ONE, nx, ny)
-		r = Nod(ORETURN, nil, nil)
+		r := Nod(ORETURN, nil, nil)
 		r.List = list(r.List, Nodbool(false))
 		nif.Nbody = list(nif.Nbody, r)
 		nrange.Nbody = list(nrange.Nbody, nif)
@@ -3101,10 +2929,11 @@
 	// and calling specific equality tests for the others.
 	// Skip blank-named fields.
 	case TSTRUCT:
-		first = nil
+		first := (*Type)(nil)
 
-		offend = 0
-		for t1 = t.Type; ; t1 = t1.Down {
+		offend := int64(0)
+		var size int64
+		for t1 := t.Type; ; t1 = t1.Down {
 			if t1 != nil && algtype1(t1.Type, nil) == AMEM && !isblanksym(t1.Sym) {
 				offend = t1.Width + t1.Type.Width
 				if first == nil {
@@ -3153,7 +2982,7 @@
 	}
 
 	// return true
-	r = Nod(ORETURN, nil, nil)
+	r := Nod(ORETURN, nil, nil)
 
 	r.List = list(r.List, Nodbool(true))
 	fn.Nbody = list(fn.Nbody, r)
@@ -3174,7 +3003,7 @@
 	// In this case it can happen if we need to generate an ==
 	// for a struct containing a reflect.Value, which itself has
 	// an unexported field of type unsafe.Pointer.
-	old_safemode = safemode
+	old_safemode := safemode
 
 	safemode = 0
 	funccompile(fn)
@@ -3182,18 +3011,16 @@
 }
 
 func ifacelookdot(s *Sym, t *Type, followptr *int, ignorecase int) *Type {
-	var i int
-	var c int
-	var d int
-	var m *Type
-
 	*followptr = 0
 
 	if t == nil {
 		return nil
 	}
 
-	for d = 0; d < len(dotlist); d++ {
+	var m *Type
+	var i int
+	var c int
+	for d := 0; d < len(dotlist); d++ {
 		c = adddot1(s, t, d, &m, ignorecase)
 		if c > 1 {
 			Yyerror("%v.%v is ambiguous", Tconv(t, 0), Sconv(s, 0))
@@ -3221,14 +3048,7 @@
 }
 
 func implements(t *Type, iface *Type, m **Type, samename **Type, ptr *int) bool {
-	var t0 *Type
-	var im *Type
-	var tm *Type
-	var rcvr *Type
-	var imtype *Type
-	var followptr int
-
-	t0 = t
+	t0 := t
 	if t == nil {
 		return false
 	}
@@ -3238,7 +3058,8 @@
 	// and then do one loop.
 
 	if t.Etype == TINTER {
-		for im = iface.Type; im != nil; im = im.Down {
+		var tm *Type
+		for im := iface.Type; im != nil; im = im.Down {
 			for tm = t.Type; tm != nil; tm = tm.Down {
 				if tm.Sym == im.Sym {
 					if Eqtype(tm.Type, im.Type) {
@@ -3265,7 +3086,11 @@
 	if t != nil {
 		expandmeth(t)
 	}
-	for im = iface.Type; im != nil; im = im.Down {
+	var tm *Type
+	var imtype *Type
+	var followptr int
+	var rcvr *Type
+	for im := iface.Type; im != nil; im = im.Down {
 		imtype = methodfunc(im.Type, nil)
 		tm = ifacelookdot(im.Sym, t, &followptr, 0)
 		if tm == nil || tm.Nointerface || !Eqtype(methodfunc(tm.Type, nil), imtype) {
@@ -3303,13 +3128,11 @@
  * all the invalid conversions (like ptr -> bool)
  */
 func Simsimtype(t *Type) int {
-	var et int
-
 	if t == nil {
 		return 0
 	}
 
-	et = int(Simtype[t.Etype])
+	et := int(Simtype[t.Etype])
 	switch et {
 	case TPTR32:
 		et = TUINT32
@@ -3339,21 +3162,19 @@
 }
 
 func list1(n *Node) *NodeList {
-	var l *NodeList
-
 	if n == nil {
 		return nil
 	}
 	if n.Op == OBLOCK && n.Ninit == nil {
 		// Flatten list and steal storage.
 		// Poison pointer to catch errant uses.
-		l = n.List
+		l := n.List
 
 		n.List = nil
 		return l
 	}
 
-	l = new(NodeList)
+	l := new(NodeList)
 	l.N = n
 	l.End = l
 	return l
@@ -3364,16 +3185,12 @@
 }
 
 func listsort(l **NodeList, f func(*Node, *Node) int) {
-	var l1 *NodeList
-	var l2 *NodeList
-	var le *NodeList
-
 	if *l == nil || (*l).Next == nil {
 		return
 	}
 
-	l1 = *l
-	l2 = *l
+	l1 := *l
+	l2 := *l
 	for {
 		l2 = l2.Next
 		if l2 == nil {
@@ -3405,6 +3222,7 @@
 
 	// now l1 == *l; and l1 < l2
 
+	var le *NodeList
 	for (l1 != nil) && (l2 != nil) {
 		for (l1.Next != nil) && f(l1.Next.N, l2.N) < 0 {
 			l1 = l1.Next
@@ -3427,9 +3245,7 @@
 }
 
 func listtreecopy(l *NodeList) *NodeList {
-	var out *NodeList
-
-	out = nil
+	out := (*NodeList)(nil)
 	for ; l != nil; l = l.Next {
 		out = list(out, treecopy(l.N))
 	}
@@ -3437,9 +3253,7 @@
 }
 
 func liststmt(l *NodeList) *Node {
-	var n *Node
-
-	n = Nod(OBLOCK, nil, nil)
+	n := Nod(OBLOCK, nil, nil)
 	n.List = l
 	if l != nil {
 		n.Lineno = l.N.Lineno
@@ -3451,9 +3265,7 @@
  * return nelem of list
  */
 func count(l *NodeList) int {
-	var n int64
-
-	n = 0
+	n := int64(0)
 	for ; l != nil; l = l.Next {
 		n++
 	}
@@ -3468,10 +3280,9 @@
  * return nelem of list
  */
 func structcount(t *Type) int {
-	var v int
 	var s Iter
 
-	v = 0
+	v := 0
 	for t = Structfirst(&s, &t); t != nil; t = structnext(&s) {
 		v++
 	}
@@ -3486,7 +3297,6 @@
 func powtwo(n *Node) int {
 	var v uint64
 	var b uint64
-	var i int
 
 	if n == nil || n.Op != OLITERAL || n.Type == nil {
 		goto no
@@ -3497,7 +3307,7 @@
 
 	v = uint64(Mpgetfix(n.Val.U.Xval))
 	b = 1
-	for i = 0; i < 64; i++ {
+	for i := 0; i < 64; i++ {
 		if b == v {
 			return i
 		}
@@ -3510,7 +3320,7 @@
 
 	v = -v
 	b = 1
-	for i = 0; i < 64; i++ {
+	for i := 0; i < 64; i++ {
 		if b == v {
 			return i + 1000
 		}
@@ -3559,17 +3369,7 @@
  * see hacker's delight chapter 10
  */
 func Smagic(m *Magic) {
-	var p int
-	var ad uint64
-	var anc uint64
-	var delta uint64
-	var q1 uint64
-	var r1 uint64
-	var q2 uint64
-	var r2 uint64
-	var t uint64
 	var mask uint64
-	var two31 uint64
 
 	m.Bad = 0
 	switch m.W {
@@ -3590,10 +3390,10 @@
 		mask = 0xffffffffffffffff
 	}
 
-	two31 = mask ^ (mask >> 1)
+	two31 := mask ^ (mask >> 1)
 
-	p = m.W - 1
-	ad = uint64(m.Sd)
+	p := m.W - 1
+	ad := uint64(m.Sd)
 	if m.Sd < 0 {
 		ad = -uint64(m.Sd)
 	}
@@ -3604,22 +3404,23 @@
 		return
 	}
 
-	t = two31
+	t := two31
 	ad &= mask
 
-	anc = t - 1 - t%ad
+	anc := t - 1 - t%ad
 	anc &= mask
 
-	q1 = two31 / anc
-	r1 = two31 - q1*anc
+	q1 := two31 / anc
+	r1 := two31 - q1*anc
 	q1 &= mask
 	r1 &= mask
 
-	q2 = two31 / ad
-	r2 = two31 - q2*ad
+	q2 := two31 / ad
+	r2 := two31 - q2*ad
 	q2 &= mask
 	r2 &= mask
 
+	var delta uint64
 	for {
 		p++
 		q1 <<= 1
@@ -3665,15 +3466,7 @@
  * see hacker's delight chapter 10
  */
 func Umagic(m *Magic) {
-	var p int
-	var nc uint64
-	var delta uint64
-	var q1 uint64
-	var r1 uint64
-	var q2 uint64
-	var r2 uint64
 	var mask uint64
-	var two31 uint64
 
 	m.Bad = 0
 	m.Ua = 0
@@ -3696,7 +3489,7 @@
 		mask = 0xffffffffffffffff
 	}
 
-	two31 = mask ^ (mask >> 1)
+	two31 := mask ^ (mask >> 1)
 
 	m.Ud &= mask
 	if m.Ud == 0 || m.Ud == two31 {
@@ -3704,19 +3497,20 @@
 		return
 	}
 
-	nc = mask - (-m.Ud&mask)%m.Ud
-	p = m.W - 1
+	nc := mask - (-m.Ud&mask)%m.Ud
+	p := m.W - 1
 
-	q1 = two31 / nc
-	r1 = two31 - q1*nc
+	q1 := two31 / nc
+	r1 := two31 - q1*nc
 	q1 &= mask
 	r1 &= mask
 
-	q2 = (two31 - 1) / m.Ud
-	r2 = (two31 - 1) - q2*m.Ud
+	q2 := (two31 - 1) / m.Ud
+	r2 := (two31 - 1) - q2*m.Ud
 	q2 &= mask
 	r2 &= mask
 
+	var delta uint64
 	for {
 		p++
 		if r1 >= nc-r1 {
@@ -3811,17 +3605,14 @@
 }
 
 func mkpkg(path_ *Strlit) *Pkg {
-	var p *Pkg
-	var h int
-
-	h = int(stringhash(path_.S) & uint32(len(phash)-1))
-	for p = phash[h]; p != nil; p = p.Link {
+	h := int(stringhash(path_.S) & uint32(len(phash)-1))
+	for p := phash[h]; p != nil; p = p.Link {
 		if p.Path.S == path_.S {
 			return p
 		}
 	}
 
-	p = new(Pkg)
+	p := new(Pkg)
 	p.Path = path_
 	p.Prefix = pathtoprefix(path_.S)
 	p.Link = phash[h]
@@ -3836,13 +3627,11 @@
 }
 
 func addinit(np **Node, init *NodeList) {
-	var n *Node
-
 	if init == nil {
 		return
 	}
 
-	n = *np
+	n := *np
 	switch n.Op {
 	// There may be multiple refs to this node;
 	// introduce OCONVNOP to hold init list.
@@ -3865,23 +3654,21 @@
 }
 
 func isbadimport(path_ *Strlit) bool {
-	var i int
-	var s string
-	var r uint
-
 	if len(path_.S) != len(path_.S) {
 		Yyerror("import path contains NUL")
 		return true
 	}
 
-	for i = 0; i < len(reservedimports); i++ {
+	for i := 0; i < len(reservedimports); i++ {
 		if path_.S == reservedimports[i] {
 			Yyerror("import path \"%s\" is reserved and cannot be used", path_.S)
 			return true
 		}
 	}
 
+	var s string
 	_ = s
+	var r uint
 	_ = r
 	for _, r := range path_.S {
 		if r == utf8.RuneError {
@@ -3914,14 +3701,12 @@
 }
 
 func checknil(x *Node, init **NodeList) {
-	var n *Node
-
 	if Isinter(x.Type) {
 		x = Nod(OITAB, x, nil)
 		typecheck(&x, Erv)
 	}
 
-	n = Nod(OCHECKNIL, x, nil)
+	n := Nod(OCHECKNIL, x, nil)
 	n.Typecheck = 1
 	*init = list(*init, n)
 }
diff --git a/src/cmd/internal/gc/swt.go b/src/cmd/internal/gc/swt.go
index 7c25041..81eb56c 100644
--- a/src/cmd/internal/gc/swt.go
+++ b/src/cmd/internal/gc/swt.go
@@ -35,9 +35,7 @@
 var C *Case
 
 func dumpcase(c0 *Case) {
-	var c *Case
-
-	for c = c0; c != nil; c = c.link {
+	for c := c0; c != nil; c = c.link {
 		switch c.type_ {
 		case Tdefault:
 			fmt.Printf("case-default\n")
@@ -104,11 +102,6 @@
 }
 
 func exprcmp(c1 *Case, c2 *Case) int {
-	var ct int
-	var n int
-	var n1 *Node
-	var n2 *Node
-
 	// sort non-constants last
 	if c1.type_ != Texprconst {
 		return +1
@@ -117,11 +110,11 @@
 		return -1
 	}
 
-	n1 = c1.node.Left
-	n2 = c2.node.Left
+	n1 := c1.node.Left
+	n2 := c2.node.Left
 
 	// sort by type (for switches on interface)
-	ct = int(n1.Val.Ctype)
+	ct := int(n1.Val.Ctype)
 
 	if ct != int(n2.Val.Ctype) {
 		return ct - int(n2.Val.Ctype)
@@ -135,7 +128,7 @@
 	}
 
 	// sort by constant value
-	n = 0
+	n := 0
 
 	switch ct {
 	case CTFLT:
@@ -181,16 +174,12 @@
 }
 
 func csort(l *Case, f func(*Case, *Case) int) *Case {
-	var l1 *Case
-	var l2 *Case
-	var le *Case
-
 	if l == nil || l.link == nil {
 		return l
 	}
 
-	l1 = l
-	l2 = l
+	l1 := l
+	l2 := l
 	for {
 		l2 = l2.link
 		if l2 == nil {
@@ -217,7 +206,7 @@
 		l2 = l2.link
 	}
 
-	le = l
+	le := l
 
 	for {
 		if l1 == nil {
@@ -270,31 +259,24 @@
  * deal with fallthrough, break, unreachable statements
  */
 func casebody(sw *Node, typeswvar *Node) {
-	var n *Node
-	var c *Node
-	var last *Node
-	var def *Node
-	var cas *NodeList
-	var stat *NodeList
-	var l *NodeList
-	var lc *NodeList
-	var go_ *Node
-	var br *Node
-	var lno int32
-	var needvar bool
-
 	if sw.List == nil {
 		return
 	}
 
-	lno = setlineno(sw)
+	lno := setlineno(sw)
 
-	cas = nil  // cases
-	stat = nil // statements
-	def = nil  // defaults
-	br = Nod(OBREAK, nil, nil)
+	cas := (*NodeList)(nil)  // cases
+	stat := (*NodeList)(nil) // statements
+	def := (*Node)(nil)      // defaults
+	br := Nod(OBREAK, nil, nil)
 
-	for l = sw.List; l != nil; l = l.Next {
+	var c *Node
+	var go_ *Node
+	var needvar bool
+	var lc *NodeList
+	var last *Node
+	var n *Node
+	for l := sw.List; l != nil; l = l.Next {
 		n = l.N
 		setlineno(n)
 		if n.Op != OXCASE {
@@ -333,9 +315,7 @@
 
 		stat = list(stat, Nod(OLABEL, go_.Left, nil))
 		if typeswvar != nil && needvar && n.Nname != nil {
-			var l *NodeList
-
-			l = list1(Nod(ODCL, n.Nname, nil))
+			l := list1(Nod(ODCL, n.Nname, nil))
 			l = list(l, Nod(OAS, n.Nname, typeswvar))
 			typechecklist(l, Etop)
 			stat = concat(stat, l)
@@ -375,16 +355,12 @@
 
 func mkcaselist(sw *Node, arg int) *Case {
 	var n *Node
-	var c *Case
 	var c1 *Case
-	var c2 *Case
-	var l *NodeList
-	var ord int
 
-	c = nil
-	ord = 0
+	c := (*Case)(nil)
+	ord := 0
 
-	for l = sw.List; l != nil; l = l.Next {
+	for l := sw.List; l != nil; l = l.Next {
 		n = l.N
 		c1 = new(Case)
 		c1.link = c
@@ -444,7 +420,8 @@
 	switch arg {
 	case Stype:
 		c = csort(c, typecmp)
-		for c1 = c; c1 != nil; c1 = c1.link {
+		var c2 *Case
+		for c1 := c; c1 != nil; c1 = c1.link {
 			for c2 = c1.link; c2 != nil && c2.hash == c1.hash; c2 = c2.link {
 				if c1.type_ == Ttypenil || c1.type_ == Tdefault {
 					break
@@ -463,7 +440,7 @@
 		Strue,
 		Sfalse:
 		c = csort(c, exprcmp)
-		for c1 = c; c1.link != nil; c1 = c1.link {
+		for c1 := c; c1.link != nil; c1 = c1.link {
 			if exprcmp(c1, c1.link) != 0 {
 				continue
 			}
@@ -481,17 +458,12 @@
 var exprname *Node
 
 func exprbsw(c0 *Case, ncase int, arg int) *Node {
-	var cas *NodeList
-	var a *Node
-	var n *Node
-	var c *Case
-	var i int
-	var half int
-	var lno int
-
-	cas = nil
+	cas := (*NodeList)(nil)
 	if ncase < Ncase {
-		for i = 0; i < ncase; i++ {
+		var a *Node
+		var n *Node
+		var lno int
+		for i := 0; i < ncase; i++ {
 			n = c0.node
 			lno = int(setlineno(n))
 
@@ -520,13 +492,13 @@
 	}
 
 	// find the middle and recur
-	c = c0
+	c := c0
 
-	half = ncase >> 1
-	for i = 1; i < half; i++ {
+	half := ncase >> 1
+	for i := 1; i < half; i++ {
 		c = c.link
 	}
-	a = Nod(OIF, nil, nil)
+	a := Nod(OIF, nil, nil)
 	a.Ntest = Nod(OLE, exprname, c.node.Left)
 	typecheck(&a.Ntest, Erv)
 	a.Nbody = list1(exprbsw(c0, half, arg))
@@ -539,19 +511,9 @@
  * rebuild case statements into if .. goto
  */
 func exprswitch(sw *Node) {
-	var def *Node
-	var cas *NodeList
-	var a *Node
-	var c0 *Case
-	var c *Case
-	var c1 *Case
-	var t *Type
-	var arg int
-	var ncase int
-
 	casebody(sw, nil)
 
-	arg = Snorm
+	arg := Snorm
 	if Isconst(sw.Ntest, CTBOOL) {
 		arg = Strue
 		if sw.Ntest.Val.U.Bval == 0 {
@@ -560,7 +522,7 @@
 	}
 
 	walkexpr(&sw.Ntest, &sw.Ninit)
-	t = sw.Type
+	t := sw.Type
 	if t == nil {
 		return
 	}
@@ -570,7 +532,7 @@
 	 */
 	exprname = nil
 
-	cas = nil
+	cas := (*NodeList)(nil)
 	if arg == Strue || arg == Sfalse {
 		exprname = Nodbool(arg == Strue)
 	} else if consttype(sw.Ntest) >= 0 {
@@ -582,7 +544,8 @@
 		typechecklist(cas, Etop)
 	}
 
-	c0 = mkcaselist(sw, arg)
+	c0 := mkcaselist(sw, arg)
+	var def *Node
 	if c0 != nil && c0.type_ == Tdefault {
 		def = c0.node.Right
 		c0 = c0.link
@@ -590,6 +553,10 @@
 		def = Nod(OBREAK, nil, nil)
 	}
 
+	var c *Case
+	var a *Node
+	var ncase int
+	var c1 *Case
 loop:
 	if c0 == nil {
 		cas = list(cas, def)
@@ -639,13 +606,8 @@
 var boolname *Node
 
 func typeone(t *Node) *Node {
-	var init *NodeList
-	var a *Node
-	var b *Node
-	var var_ *Node
-
-	var_ = t.Nname
-	init = nil
+	var_ := t.Nname
+	init := (*NodeList)(nil)
 	if var_ == nil {
 		typecheck(&nblank, Erv|Easgn)
 		var_ = nblank
@@ -653,9 +615,9 @@
 		init = list1(Nod(ODCL, var_, nil))
 	}
 
-	a = Nod(OAS2, nil, nil)
+	a := Nod(OAS2, nil, nil)
 	a.List = list(list1(var_), boolname) // var,bool =
-	b = Nod(ODOTTYPE, facename, nil)
+	b := Nod(ODOTTYPE, facename, nil)
 	b.Type = t.Left.Type // interface.(type)
 	a.Rlist = list1(b)
 	typecheck(&a, Etop)
@@ -669,17 +631,12 @@
 }
 
 func typebsw(c0 *Case, ncase int) *Node {
-	var cas *NodeList
-	var a *Node
-	var n *Node
-	var c *Case
-	var i int
-	var half int
-
-	cas = nil
+	cas := (*NodeList)(nil)
 
 	if ncase < Ncase {
-		for i = 0; i < ncase; i++ {
+		var n *Node
+		var a *Node
+		for i := 0; i < ncase; i++ {
 			n = c0.node
 			if c0.type_ != Ttypeconst {
 				Fatal("typebsw")
@@ -696,13 +653,13 @@
 	}
 
 	// find the middle and recur
-	c = c0
+	c := c0
 
-	half = ncase >> 1
-	for i = 1; i < half; i++ {
+	half := ncase >> 1
+	for i := 1; i < half; i++ {
 		c = c.link
 	}
-	a = Nod(OIF, nil, nil)
+	a := Nod(OIF, nil, nil)
 	a.Ntest = Nod(OLE, hashname, Nodintconst(int64(c.hash)))
 	typecheck(&a.Ntest, Erv)
 	a.Nbody = list1(typebsw(c0, half))
@@ -716,18 +673,6 @@
  * into if statements
  */
 func typeswitch(sw *Node) {
-	var def *Node
-	var cas *NodeList
-	var hash *NodeList
-	var a *Node
-	var n *Node
-	var c *Case
-	var c0 *Case
-	var c1 *Case
-	var ncase int
-	var t *Type
-	var v Val
-
 	if sw.Ntest == nil {
 		return
 	}
@@ -743,7 +688,7 @@
 		return
 	}
 
-	cas = nil
+	cas := (*NodeList)(nil)
 
 	/*
 	 * predeclare temporary variables
@@ -751,7 +696,7 @@
 	 */
 	facename = temp(sw.Ntest.Right.Type)
 
-	a = Nod(OAS, facename, sw.Ntest.Right)
+	a := Nod(OAS, facename, sw.Ntest.Right)
 	typecheck(&a, Etop)
 	cas = list(cas, a)
 
@@ -763,7 +708,7 @@
 	hashname = temp(Types[TUINT32])
 	typecheck(&hashname, Erv)
 
-	t = sw.Ntest.Right.Type
+	t := sw.Ntest.Right.Type
 	if isnilinter(t) {
 		a = syslook("efacethash", 1)
 	} else {
@@ -776,7 +721,8 @@
 	typecheck(&a, Etop)
 	cas = list(cas, a)
 
-	c0 = mkcaselist(sw, Stype)
+	c0 := mkcaselist(sw, Stype)
+	var def *Node
 	if c0 != nil && c0.type_ == Tdefault {
 		def = c0.node.Right
 		c0 = c0.link
@@ -787,7 +733,9 @@
 	/*
 	 * insert if statement into each case block
 	 */
-	for c = c0; c != nil; c = c.link {
+	var v Val
+	var n *Node
+	for c := c0; c != nil; c = c.link {
 		n = c.node
 		switch c.type_ {
 		case Ttypenil:
@@ -807,6 +755,10 @@
 	/*
 	 * generate list of if statements, binary search for constant sequences
 	 */
+	var ncase int
+	var c1 *Case
+	var hash *NodeList
+	var c *Case
 	for c0 != nil {
 		if c0.type_ != Ttypeconst {
 			n = c0.node
@@ -895,22 +847,11 @@
  */
 func typecheckswitch(n *Node) {
 	var top int
-	var lno int
-	var ptr int
-	var nilonly string
 	var t *Type
-	var badtype *Type
-	var missing *Type
-	var have *Type
-	var l *NodeList
-	var ll *NodeList
-	var ncase *Node
-	var nvar *Node
-	var def *Node
 
-	lno = int(lineno)
+	lno := int(lineno)
 	typechecklist(n.Ninit, Etop)
-	nilonly = ""
+	nilonly := ""
 
 	if n.Ntest != nil && n.Ntest.Op == OTYPESW {
 		// type switch
@@ -933,6 +874,7 @@
 			t = Types[TBOOL]
 		}
 		if t != nil {
+			var badtype *Type
 			if okforeq[t.Etype] == 0 {
 				Yyerror("cannot switch on %v", Nconv(n.Ntest, obj.FmtLong))
 			} else if t.Etype == TARRAY && !Isfixedarray(t) {
@@ -951,8 +893,14 @@
 
 	n.Type = t
 
-	def = nil
-	for l = n.List; l != nil; l = l.Next {
+	def := (*Node)(nil)
+	var ptr int
+	var have *Type
+	var nvar *Node
+	var ll *NodeList
+	var missing *Type
+	var ncase *Node
+	for l := n.List; l != nil; l = l.Next {
 		ncase = l.N
 		setlineno(n)
 		if ncase.List == nil {
diff --git a/src/cmd/internal/gc/typecheck.go b/src/cmd/internal/gc/typecheck.go
index 3cd7408..9fa1930 100644
--- a/src/cmd/internal/gc/typecheck.go
+++ b/src/cmd/internal/gc/typecheck.go
@@ -24,10 +24,8 @@
  * resolve ONONAME to definition, if any.
  */
 func resolve(n *Node) *Node {
-	var r *Node
-
 	if n != nil && n.Op == ONONAME && n.Sym != nil {
-		r = n.Sym.Def
+		r := n.Sym.Def
 		if r != nil {
 			if r.Op != OIOTA {
 				n = r
@@ -80,15 +78,12 @@
 var typekind_buf string
 
 func typekind(t *Type) string {
-	var et int
-	var s string
-
 	if Isslice(t) {
 		return "slice"
 	}
-	et = int(t.Etype)
+	et := int(t.Etype)
 	if 0 <= et && et < len(_typekind) {
-		s = _typekind[et]
+		s := _typekind[et]
 		if s != "" {
 			return s
 		}
@@ -104,9 +99,7 @@
  * to print constant definition loops.
  */
 func sprint_depchain(fmt_ *string, stack *NodeList, cur *Node, first *Node) {
-	var l *NodeList
-
-	for l = stack; l != nil; l = l.Next {
+	for l := stack; l != nil; l = l.Next {
 		if l.N.Op == cur.Op {
 			if l.N != first {
 				sprint_depchain(fmt_, l.Next, l.N, first)
@@ -127,22 +120,17 @@
 var typecheck_tcfree *NodeList
 
 func typecheck(np **Node, top int) *Node {
-	var n *Node
-	var lno int
-	var fmt_ string
-	var l *NodeList
-
 	// cannot type check until all the source has been parsed
 	if typecheckok == 0 {
 		Fatal("early typecheck")
 	}
 
-	n = *np
+	n := *np
 	if n == nil {
 		return nil
 	}
 
-	lno = int(setlineno(n))
+	lno := int(setlineno(n))
 
 	// Skip over parens.
 	for n.Op == OPAREN {
@@ -173,6 +161,7 @@
 	if n.Typecheck == 2 {
 		// Typechecking loop. Trying printing a meaningful message,
 		// otherwise a stack trace of typechecking.
+		var fmt_ string
 		switch n.Op {
 		// We can already diagnose variables used as types.
 		case ONAME:
@@ -193,7 +182,7 @@
 
 		if nsavederrors+nerrors == 0 {
 			fmt_ = ""
-			for l = typecheck_tcstack; l != nil; l = l.Next {
+			for l := typecheck_tcstack; l != nil; l = l.Next {
 				fmt_ += fmt.Sprintf("\n\t%v %v", l.N.Line(), Nconv(l.N, 0))
 			}
 			Yyerror("typechecking loop involving %v%s", Nconv(n, 0), fmt_)
@@ -205,6 +194,7 @@
 
 	n.Typecheck = 2
 
+	var l *NodeList
 	if typecheck_tcfree != nil {
 		l = typecheck_tcfree
 		typecheck_tcfree = l.Next
@@ -270,9 +260,7 @@
 // except for constants of numerical kind, which are acceptable
 // whenever they can be represented by a value of type int.
 func indexlit(np **Node) {
-	var n *Node
-
-	n = *np
+	n := *np
 	if n == nil || !isideal(n.Type) {
 		return
 	}
@@ -292,13 +280,11 @@
 	var aop int
 	var op int
 	var ptr int
-	var n *Node
 	var l *Node
 	var r *Node
 	var lo *Node
 	var mid *Node
 	var hi *Node
-	var args *NodeList
 	var ok int
 	var ntop int
 	var t *Type
@@ -308,11 +294,9 @@
 	var badtype *Type
 	var v Val
 	var why string
-	var desc string
-	var descbuf string
 	var x int64
 
-	n = *np
+	n := *np
 
 	if n.Sym != nil {
 		if n.Op == ONAME && n.Etype != 0 && top&Ecall == 0 {
@@ -1046,7 +1030,7 @@
 		}
 
 		defaultlit(&n.Left, nil)
-		l = n.Left
+		l := n.Left
 		if l.Op == OTYPE {
 			if n.Isddd != 0 || l.Type.Bound == -100 {
 				if l.Type.Broke == 0 {
@@ -1074,7 +1058,7 @@
 		} else {
 			typechecklist(n.List, Erv)
 		}
-		t = l.Type
+		t := l.Type
 		if t == nil {
 			goto error
 		}
@@ -1091,7 +1075,7 @@
 			// information further down the call chain to know if we
 			// were testing a method receiver for unexported fields.
 			// It isn't necessary, so just do a sanity check.
-			tp = getthisx(t).Type.Type
+			tp := getthisx(t).Type.Type
 
 			if l.Left == nil || !Eqtype(l.Left.Type, tp) {
 				Fatal("method receiver")
@@ -1105,8 +1089,8 @@
 			}
 		}
 
-		descbuf = fmt.Sprintf("argument to %v", Nconv(n.Left, 0))
-		desc = descbuf
+		descbuf := fmt.Sprintf("argument to %v", Nconv(n.Left, 0))
+		desc := descbuf
 		typecheckaste(OCALL, n.Left, int(n.Isddd), getinargx(t), n.List, desc)
 		ok |= Etop
 		if t.Outtuple == 0 {
@@ -1114,7 +1098,7 @@
 		}
 		ok |= Erv
 		if t.Outtuple == 1 {
-			t = getoutargx(l.Type).Type
+			t := getoutargx(l.Type).Type
 			if t == nil {
 				goto error
 			}
@@ -1145,8 +1129,8 @@
 		typecheck(&n.Left, Erv)
 		defaultlit(&n.Left, nil)
 		implicitstar(&n.Left)
-		l = n.Left
-		t = l.Type
+		l := n.Left
+		t := l.Type
 		if t == nil {
 			goto error
 		}
@@ -1167,7 +1151,7 @@
 				goto badcall1
 			}
 			if Isconst(l, CTCPLX) {
-				r = n
+				r := n
 				if n.Op == OREAL {
 					n = nodfltconst(&l.Val.U.Cval.Real)
 				} else {
@@ -1184,7 +1168,7 @@
 		switch t.Etype {
 		case TSTRING:
 			if Isconst(l, CTSTR) {
-				r = Nod(OXXX, nil, nil)
+				r := Nod(OXXX, nil, nil)
 				Nodconst(r, Types[TINT], int64(len(l.Val.U.Sval.S)))
 				r.Orig = n
 				n = r
@@ -1197,7 +1181,7 @@
 			if callrecv(l) { // has call or receive
 				break
 			}
-			r = Nod(OXXX, nil, nil)
+			r := Nod(OXXX, nil, nil)
 			Nodconst(r, Types[TINT], t.Bound)
 			r.Orig = n
 			n = r
@@ -1208,6 +1192,8 @@
 
 	case OCOMPLEX:
 		ok |= Erv
+		var r *Node
+		var l *Node
 		if count(n.List) == 1 {
 			typechecklist(n.List, Efnstruct)
 			if n.List.N.Op != OCALLFUNC && n.List.N.Op != OCALLMETH {
@@ -1215,7 +1201,7 @@
 				goto error
 			}
 
-			t = n.List.N.Left.Type
+			t := n.List.N.Left.Type
 			if t.Outtuple != 2 {
 				Yyerror("invalid operation: complex expects two arguments, %v returns %d results", Nconv(n.List.N, 0), t.Outtuple)
 				goto error
@@ -1246,6 +1232,7 @@
 			goto error
 		}
 
+		var t *Type
 		switch l.Type.Etype {
 		default:
 			Yyerror("invalid operation: %v (arguments have type %v, expected floating-point)", Nconv(n, 0), Tconv(l.Type, 0), r.Type)
@@ -1278,8 +1265,8 @@
 		}
 		typecheck(&n.Left, Erv)
 		defaultlit(&n.Left, nil)
-		l = n.Left
-		t = l.Type
+		l := n.Left
+		t := l.Type
 		if t == nil {
 			goto error
 		}
@@ -1297,7 +1284,7 @@
 		goto ret
 
 	case ODELETE:
-		args = n.List
+		args := n.List
 		if args == nil {
 			Yyerror("missing arguments to delete")
 			goto error
@@ -1315,8 +1302,8 @@
 
 		ok |= Etop
 		typechecklist(args, Erv)
-		l = args.N
-		r = args.Next.N
+		l := args.N
+		r := args.Next.N
 		if l.Type != nil && l.Type.Etype != TMAP {
 			Yyerror("first argument to delete must be map; have %v", Tconv(l.Type, obj.FmtLong))
 			goto error
@@ -1327,7 +1314,7 @@
 
 	case OAPPEND:
 		ok |= Erv
-		args = n.List
+		args := n.List
 		if args == nil {
 			Yyerror("missing arguments to append")
 			goto error
@@ -1339,7 +1326,7 @@
 			typechecklist(args, Erv)
 		}
 
-		t = args.N.Type
+		t := args.N.Type
 		if t == nil {
 			goto error
 		}
@@ -1394,7 +1381,7 @@
 
 	case OCOPY:
 		ok |= Etop | Erv
-		args = n.List
+		args := n.List
 		if args == nil || args.Next == nil {
 			Yyerror("missing arguments to copy")
 			goto error
@@ -1452,17 +1439,17 @@
 
 	case OMAKE:
 		ok |= Erv
-		args = n.List
+		args := n.List
 		if args == nil {
 			Yyerror("missing argument to make")
 			goto error
 		}
 
 		n.List = nil
-		l = args.N
+		l := args.N
 		args = args.Next
 		typecheck(&l, Etype)
-		t = l.Type
+		t := l.Type
 		if t == nil {
 			goto error
 		}
@@ -1486,7 +1473,7 @@
 			l = args.N
 			args = args.Next
 			typecheck(&l, Erv)
-			r = nil
+			r := (*Node)(nil)
 			if args != nil {
 				r = args.N
 				args = args.Next
@@ -1496,7 +1483,7 @@
 			if l.Type == nil || (r != nil && r.Type == nil) {
 				goto error
 			}
-			et = bool2int(checkmake(t, "len", l) < 0)
+			et := bool2int(checkmake(t, "len", l) < 0)
 			et |= bool2int(r != nil && checkmake(t, "cap", r) < 0)
 			if et != 0 {
 				goto error
@@ -1559,15 +1546,15 @@
 
 	case ONEW:
 		ok |= Erv
-		args = n.List
+		args := n.List
 		if args == nil {
 			Yyerror("missing argument to new")
 			goto error
 		}
 
-		l = args.N
+		l := args.N
 		typecheck(&l, Etype)
-		t = l.Type
+		t := l.Type
 		if t == nil {
 			goto error
 		}
@@ -1584,7 +1571,7 @@
 		OPRINTN:
 		ok |= Etop
 		typechecklist(n.List, Erv|Eindir) // Eindir: address does not escape
-		for args = n.List; args != nil; args = args.Next {
+		for args := n.List; args != nil; args = args.Next {
 			// Special case for print: int constant is int64, not int.
 			if Isconst(args.N, CTINT) {
 				defaultlit(&args.N, Types[TINT64])
@@ -1628,7 +1615,7 @@
 	case OITAB:
 		ok |= Erv
 		typecheck(&n.Left, Erv)
-		t = n.Left.Type
+		t := n.Left.Type
 		if t == nil {
 			goto error
 		}
@@ -1641,7 +1628,7 @@
 	case OSPTR:
 		ok |= Erv
 		typecheck(&n.Left, Erv)
-		t = n.Left.Type
+		t := n.Left.Type
 		if t == nil {
 			goto error
 		}
@@ -1724,7 +1711,7 @@
 		decldepth++
 		typecheck(&n.Ntest, Erv)
 		if n.Ntest != nil {
-			t = n.Ntest.Type
+			t := n.Ntest.Type
 			if t != nil && t.Etype != TBOOL {
 				Yyerror("non-bool %v used as for condition", Nconv(n.Ntest, obj.FmtLong))
 			}
@@ -1739,7 +1726,7 @@
 		typechecklist(n.Ninit, Etop)
 		typecheck(&n.Ntest, Erv)
 		if n.Ntest != nil {
-			t = n.Ntest.Type
+			t := n.Ntest.Type
 			if t != nil && t.Etype != TBOOL {
 				Yyerror("non-bool %v used as if condition", Nconv(n.Ntest, obj.FmtLong))
 			}
@@ -2049,7 +2036,7 @@
 	switch n.Op {
 	case OCONVNOP:
 		if n.Left.Op == OLITERAL && n.Type != Types[TBOOL] {
-			r = Nod(OXXX, nil, nil)
+			r := Nod(OXXX, nil, nil)
 			n.Op = OCONV
 			n.Orig = r
 			*r = *n
@@ -2135,9 +2122,7 @@
 }
 
 func checksliceindex(l *Node, r *Node, tp *Type) int {
-	var t *Type
-
-	t = r.Type
+	t := r.Type
 	if t == nil {
 		return -1
 	}
@@ -2175,9 +2160,7 @@
 }
 
 func checkdefergo(n *Node) {
-	var what string
-
-	what = "defer"
+	what := "defer"
 	if n.Op == OPROC {
 		what = "go"
 	}
@@ -2231,13 +2214,10 @@
 }
 
 func implicitstar(nn **Node) {
-	var t *Type
-	var n *Node
-
 	// insert implicit * if needed for fixed array
-	n = *nn
+	n := *nn
 
-	t = n.Type
+	t := n.Type
 	if t == nil || Isptr[t.Etype] == 0 {
 		return
 	}
@@ -2255,19 +2235,17 @@
 }
 
 func onearg(n *Node, f string, args ...interface{}) int {
-	var p string
-
 	if n.Left != nil {
 		return 0
 	}
 	if n.List == nil {
-		p = fmt.Sprintf(f, args...)
+		p := fmt.Sprintf(f, args...)
 		Yyerror("missing argument to %s: %v", p, Nconv(n, 0))
 		return -1
 	}
 
 	if n.List.Next != nil {
-		p = fmt.Sprintf(f, args...)
+		p := fmt.Sprintf(f, args...)
 		Yyerror("too many arguments to %s: %v", p, Nconv(n, 0))
 		n.Left = n.List.N
 		n.List = nil
@@ -2307,9 +2285,7 @@
 }
 
 func lookdot1(errnode *Node, s *Sym, t *Type, f *Type, dostrcmp int) *Type {
-	var r *Type
-
-	r = nil
+	r := (*Type)(nil)
 	for ; f != nil; f = f.Down {
 		if dostrcmp != 0 && f.Sym.Name == s.Name {
 			return f
@@ -2335,14 +2311,10 @@
 }
 
 func looktypedot(n *Node, t *Type, dostrcmp int) bool {
-	var f1 *Type
-	var f2 *Type
-	var s *Sym
-
-	s = n.Right.Sym
+	s := n.Right.Sym
 
 	if t.Etype == TINTER {
-		f1 = lookdot1(n, s, t, t.Type, dostrcmp)
+		f1 := lookdot1(n, s, t, t.Type, dostrcmp)
 		if f1 == nil {
 			return false
 		}
@@ -2356,7 +2328,7 @@
 
 	// Find the base type: methtype will fail if t
 	// is not of the form T or *T.
-	f2 = methtype(t, 0)
+	f2 := methtype(t, 0)
 
 	if f2 == nil {
 		return false
@@ -2389,21 +2361,15 @@
 }
 
 func lookdot(n *Node, t *Type, dostrcmp int) bool {
-	var f1 *Type
-	var f2 *Type
-	var tt *Type
-	var rcvr *Type
-	var s *Sym
-
-	s = n.Right.Sym
+	s := n.Right.Sym
 
 	dowidth(t)
-	f1 = nil
+	f1 := (*Type)(nil)
 	if t.Etype == TSTRUCT || t.Etype == TINTER {
 		f1 = lookdot1(n, s, t, t.Type, dostrcmp)
 	}
 
-	f2 = nil
+	f2 := (*Type)(nil)
 	if n.Left.Type == t || n.Left.Type.Sym == nil {
 		f2 = methtype(t, 0)
 		if f2 != nil {
@@ -2437,9 +2403,9 @@
 	}
 
 	if f2 != nil {
-		tt = n.Left.Type
+		tt := n.Left.Type
 		dowidth(tt)
-		rcvr = getthisx(f2.Type).Type.Type
+		rcvr := getthisx(f2.Type).Type.Type
 		if !Eqtype(rcvr, tt) {
 			if int(rcvr.Etype) == Tptr && Eqtype(rcvr.Type, tt) {
 				checklvalue(n.Left, "call pointer method on")
@@ -2490,9 +2456,7 @@
 }
 
 func hasddd(t *Type) bool {
-	var tl *Type
-
-	for tl = t.Type; tl != nil; tl = tl.Down {
+	for tl := t.Type; tl != nil; tl = tl.Down {
 		if tl.Isddd != 0 {
 			return true
 		}
@@ -2502,11 +2466,8 @@
 }
 
 func downcount(t *Type) int {
-	var tl *Type
-	var n int
-
-	n = 0
-	for tl = t.Type; tl != nil; tl = tl.Down {
+	n := 0
+	for tl := t.Type; tl != nil; tl = tl.Down {
 		n++
 	}
 
@@ -2518,15 +2479,11 @@
  */
 func typecheckaste(op int, call *Node, isddd int, tstruct *Type, nl *NodeList, desc string) {
 	var t *Type
-	var tl *Type
-	var tn *Type
 	var n *Node
-	var lno int
-	var why string
 	var n1 int
 	var n2 int
 
-	lno = int(lineno)
+	lno := int(lineno)
 
 	if tstruct.Broke != 0 {
 		goto out
@@ -2538,8 +2495,8 @@
 		if n.Type != nil {
 			if n.Type.Etype == TSTRUCT && n.Type.Funarg != 0 {
 				if !hasddd(tstruct) {
-					n1 = downcount(tstruct)
-					n2 = downcount(n.Type)
+					n1 := downcount(tstruct)
+					n2 := downcount(n.Type)
 					if n2 > n1 {
 						goto toomany
 					}
@@ -2548,8 +2505,9 @@
 					}
 				}
 
-				tn = n.Type.Type
-				for tl = tstruct.Type; tl != nil; tl = tl.Down {
+				tn := n.Type.Type
+				var why string
+				for tl := tstruct.Type; tl != nil; tl = tl.Down {
 					if tl.Isddd != 0 {
 						for ; tn != nil; tn = tn.Down {
 							if assignop(tn.Type, tl.Type.Type, &why) == 0 {
@@ -2610,7 +2568,7 @@
 		}
 	}
 
-	for tl = tstruct.Type; tl != nil; tl = tl.Down {
+	for tl := tstruct.Type; tl != nil; tl = tl.Down {
 		t = tl.Type
 		if tl.Isddd != 0 {
 			if isddd != 0 {
@@ -2692,16 +2650,12 @@
  * type check composite
  */
 func fielddup(n *Node, hash []*Node) {
-	var h uint
-	var s string
-	var a *Node
-
 	if n.Op != ONAME {
 		Fatal("fielddup: not ONAME")
 	}
-	s = n.Sym.Name
-	h = uint(stringhash(s) % uint32(len(hash)))
-	for a = hash[h]; a != nil; a = a.Ntest {
+	s := n.Sym.Name
+	h := uint(stringhash(s) % uint32(len(hash)))
+	for a := hash[h]; a != nil; a = a.Ntest {
 		if a.Sym.Name == s {
 			Yyerror("duplicate field name in struct literal: %s", s)
 			return
@@ -2713,16 +2667,7 @@
 }
 
 func keydup(n *Node, hash []*Node) {
-	var h uint
-	var b uint32
-	var d float64
-	var i int
-	var a *Node
-	var orign *Node
-	var cmp Node
-	var s string
-
-	orign = n
+	orign := n
 	if n.Op == OCONVIFACE {
 		n = n.Left
 	}
@@ -2731,6 +2676,7 @@
 		return // we dont check variables
 	}
 
+	var b uint32
 	switch n.Val.Ctype {
 	default: // unknown, bool, nil
 		b = 23
@@ -2740,7 +2686,7 @@
 		b = uint32(Mpgetfix(n.Val.U.Xval))
 
 	case CTFLT:
-		d = mpgetflt(n.Val.U.Fval)
+		d := mpgetflt(n.Val.U.Fval)
 		x := math.Float64bits(d)
 		for i := 0; i < 8; i++ {
 			b = b*PRIME1 + uint32(x&0xFF)
@@ -2749,16 +2695,16 @@
 
 	case CTSTR:
 		b = 0
-		s = n.Val.U.Sval.S
-		for i = len(n.Val.U.Sval.S); i > 0; i-- {
+		s := n.Val.U.Sval.S
+		for i := len(n.Val.U.Sval.S); i > 0; i-- {
 			b = b*PRIME1 + uint32(s[0])
 			s = s[1:]
 		}
 	}
 
-	h = uint(b % uint32(len(hash)))
-	cmp = Node{}
-	for a = hash[h]; a != nil; a = a.Ntest {
+	h := uint(b % uint32(len(hash)))
+	cmp := Node{}
+	for a := hash[h]; a != nil; a = a.Ntest {
 		cmp.Op = OEQ
 		cmp.Left = n
 		b = 0
@@ -2785,18 +2731,14 @@
 }
 
 func indexdup(n *Node, hash []*Node) {
-	var h uint
-	var a *Node
-	var b uint32
-	var c uint32
-
 	if n.Op != OLITERAL {
 		Fatal("indexdup: not OLITERAL")
 	}
 
-	b = uint32(Mpgetfix(n.Val.U.Xval))
-	h = uint(b % uint32(len(hash)))
-	for a = hash[h]; a != nil; a = a.Ntest {
+	b := uint32(Mpgetfix(n.Val.U.Xval))
+	h := uint(b % uint32(len(hash)))
+	var c uint32
+	for a := hash[h]; a != nil; a = a.Ntest {
 		c = uint32(Mpgetfix(a.Val.U.Xval))
 		if b == c {
 			Yyerror("duplicate index in array literal: %d", b)
@@ -2809,9 +2751,7 @@
 }
 
 func prime(h uint32, sr uint32) bool {
-	var n uint32
-
-	for n = 3; n <= sr; n += 2 {
+	for n := uint32(3); n <= sr; n += 2 {
 		if h%n == 0 {
 			return false
 		}
@@ -2820,15 +2760,10 @@
 }
 
 func inithash(n *Node, autohash []*Node) []*Node {
-	var h uint32
-	var sr uint32
-	var ll *NodeList
-	var i int
-
 	// count the number of entries
-	h = 0
+	h := uint32(0)
 
-	for ll = n.List; ll != nil; ll = ll.Next {
+	for ll := n.List; ll != nil; ll = ll.Next {
 		h++
 	}
 
@@ -2847,9 +2782,9 @@
 	h |= 1
 
 	// calculate sqrt of h
-	sr = h / 2
+	sr := h / 2
 
-	for i = 0; i < 5; i++ {
+	for i := 0; i < 5; i++ {
 		sr = (sr + h/sr) / 2
 	}
 
@@ -2900,25 +2835,14 @@
 }
 
 func typecheckcomplit(np **Node) {
-	var bad int
-	var i int
 	var nerr int
-	var length int64
 	var l *Node
-	var n *Node
 	var norig *Node
 	var r *Node
-	var hash []*Node
-	var ll *NodeList
 	var t *Type
-	var f *Type
-	var s *Sym
-	var s1 *Sym
-	var lno int32
-	var autohash [101]*Node
 
-	n = *np
-	lno = lineno
+	n := *np
+	lno := lineno
 
 	if n.Right == nil {
 		if n.List != nil {
@@ -2965,11 +2889,13 @@
 		n.Type = nil
 
 	case TARRAY:
-		hash = inithash(n, autohash[:])
+		var autohash [101]*Node
+		hash := inithash(n, autohash[:])
 
-		length = 0
-		i = 0
-		for ll = n.List; ll != nil; ll = ll.Next {
+		length := int64(0)
+		i := 0
+		var l *Node
+		for ll := n.List; ll != nil; ll = ll.Next {
 			l = ll.N
 			setlineno(l)
 			if l.Op != OKEY {
@@ -3017,9 +2943,11 @@
 		n.Op = OARRAYLIT
 
 	case TMAP:
-		hash = inithash(n, autohash[:])
+		var autohash [101]*Node
+		hash := inithash(n, autohash[:])
 
-		for ll = n.List; ll != nil; ll = ll.Next {
+		var l *Node
+		for ll := n.List; ll != nil; ll = ll.Next {
 			l = ll.N
 			setlineno(l)
 			if l.Op != OKEY {
@@ -3045,12 +2973,13 @@
 		n.Op = OMAPLIT
 
 	case TSTRUCT:
-		bad = 0
+		bad := 0
 		if n.List != nil && nokeys(n.List) {
 			// simple list of variables
-			f = t.Type
+			f := t.Type
 
-			for ll = n.List; ll != nil; ll = ll.Next {
+			var s *Sym
+			for ll := n.List; ll != nil; ll = ll.Next {
 				setlineno(ll.N)
 				typecheck(&ll.N, Erv)
 				if f == nil {
@@ -3080,10 +3009,15 @@
 				Yyerror("too few values in struct initializer")
 			}
 		} else {
-			hash = inithash(n, autohash[:])
+			var autohash [101]*Node
+			hash := inithash(n, autohash[:])
 
 			// keyed list
-			for ll = n.List; ll != nil; ll = ll.Next {
+			var s *Sym
+			var f *Type
+			var l *Node
+			var s1 *Sym
+			for ll := n.List; ll != nil; ll = ll.Next {
 				l = ll.N
 				setlineno(l)
 				if l.Op != OKEY {
@@ -3201,12 +3135,10 @@
 }
 
 func checkassign(stmt *Node, n *Node) {
-	var r *Node
-	var l *Node
-
 	// Variables declared in ORANGE are assigned on every iteration.
 	if n.Defn != stmt || stmt.Op == ORANGE {
-		r = outervalue(n)
+		r := outervalue(n)
+		var l *Node
 		for l = n; l != r; l = l.Left {
 			l.Assigned = 1
 			if l.Closure != nil {
@@ -3345,14 +3277,8 @@
 }
 
 func typecheckas2(n *Node) {
-	var cl int
-	var cr int
 	var ll *NodeList
 	var lr *NodeList
-	var l *Node
-	var r *Node
-	var s Iter
-	var t *Type
 
 	for ll = n.List; ll != nil; ll = ll.Next {
 		// delicate little dance.
@@ -3363,8 +3289,8 @@
 		}
 	}
 
-	cl = count(n.List)
-	cr = count(n.Rlist)
+	cl := count(n.List)
+	cr := count(n.Rlist)
 	if cl > 1 && cr == 1 {
 		typecheck(&n.Rlist.N, Erv|Efnstruct)
 	} else {
@@ -3372,6 +3298,8 @@
 	}
 	checkassignlist(n, n.List)
 
+	var l *Node
+	var r *Node
 	if cl == cr {
 		// easy
 		ll = n.List
@@ -3409,7 +3337,8 @@
 				goto mismatch
 			}
 			n.Op = OAS2FUNC
-			t = Structfirst(&s, &r.Type)
+			var s Iter
+			t := Structfirst(&s, &r.Type)
 			for ll = n.List; ll != nil; ll = ll.Next {
 				if t.Type != nil && ll.N.Type != nil {
 					checkassignto(t.Type, ll.N)
@@ -3451,7 +3380,7 @@
 			if l.Defn == n {
 				l.Type = r.Type
 			}
-			l = n.List.Next.N
+			l := n.List.Next.N
 			if l.Type != nil && l.Type.Etype != TBOOL {
 				checkassignto(Types[TBOOL], l)
 			}
@@ -3480,23 +3409,19 @@
  * type check function definition
  */
 func typecheckfunc(n *Node) {
-	var t *Type
-	var rcvr *Type
-	var l *NodeList
-
 	typecheck(&n.Nname, Erv|Easgn)
-	t = n.Nname.Type
+	t := n.Nname.Type
 	if t == nil {
 		return
 	}
 	n.Type = t
 	t.Nname = n.Nname
-	rcvr = getthisx(t).Type
+	rcvr := getthisx(t).Type
 	if rcvr != nil && n.Shortname != nil && !isblank(n.Shortname) {
 		addmethod(n.Shortname.Sym, t, true, n.Nname.Nointerface)
 	}
 
-	for l = n.Dcl; l != nil; l = l.Next {
+	for l := n.Dcl; l != nil; l = l.Next {
 		if l.N.Op == ONAME && (l.N.Class == PPARAM || l.N.Class == PPARAMOUT) {
 			l.N.Decldepth = 1
 		}
@@ -3536,10 +3461,7 @@
 var methodqueue *NodeList
 
 func domethod(n *Node) {
-	var nt *Node
-	var t *Type
-
-	nt = n.Type.Nname
+	nt := n.Type.Nname
 	typecheck(&nt, Etype)
 	if nt.Type == nil {
 		// type check failed; leave empty func
@@ -3557,7 +3479,7 @@
 	// value of its argument, a specific implementation of I may
 	// care.  The _ would suppress the assignment to that argument
 	// while generating a call, so remove it.
-	for t = getinargx(nt.Type).Type; t != nil; t = t.Down {
+	for t := getinargx(nt.Type).Type; t != nil; t = t.Down {
 		if t.Sym != nil && t.Sym.Name == "_" {
 			t.Sym = nil
 		}
@@ -3571,11 +3493,6 @@
 var mapqueue *NodeList
 
 func copytype(n *Node, t *Type) {
-	var maplineno int
-	var embedlineno int
-	var lno int
-	var l *NodeList
-
 	if t.Etype == TFORW {
 		// This type isn't computed yet; when it is, update n.
 		t.Copyto = list(t.Copyto, n)
@@ -3583,10 +3500,10 @@
 		return
 	}
 
-	maplineno = int(n.Type.Maplineno)
-	embedlineno = int(n.Type.Embedlineno)
+	maplineno := int(n.Type.Maplineno)
+	embedlineno := int(n.Type.Embedlineno)
 
-	l = n.Type.Copyto
+	l := n.Type.Copyto
 	*n.Type = *t
 
 	t = n.Type
@@ -3607,7 +3524,7 @@
 	}
 
 	// Double-check use of type as embedded type.
-	lno = int(lineno)
+	lno := int(lineno)
 
 	if embedlineno != 0 {
 		lineno = int32(embedlineno)
@@ -3626,17 +3543,13 @@
 }
 
 func typecheckdeftype(n *Node) {
-	var lno int
-	var t *Type
-	var l *NodeList
-
 	ntypecheckdeftype++
-	lno = int(lineno)
+	lno := int(lineno)
 	setlineno(n)
 	n.Type.Sym = n.Sym
 	n.Typecheck = 1
 	typecheck(&n.Ntype, Etype)
-	t = n.Ntype.Type
+	t := n.Ntype.Type
 	if t == nil {
 		n.Diag = 1
 		n.Type = nil
@@ -3661,6 +3574,7 @@
 	// try to resolve the method types for the interfaces
 	// we just read.
 	if ntypecheckdeftype == 1 {
+		var l *NodeList
 		for {
 			l = methodqueue
 			if l == nil {
@@ -3672,7 +3586,7 @@
 			}
 		}
 
-		for l = mapqueue; l != nil; l = l.Next {
+		for l := mapqueue; l != nil; l = l.Next {
 			lineno = l.N.Type.Maplineno
 			maptype(l.N.Type, Types[TBOOL])
 		}
@@ -3693,13 +3607,7 @@
 }
 
 func typecheckdef(n *Node) *Node {
-	var lno int
-	var nerrors0 int
-	var e *Node
-	var t *Type
-	var l *NodeList
-
-	lno = int(lineno)
+	lno := int(lineno)
 	setlineno(n)
 
 	if n.Op == ONONAME {
@@ -3721,7 +3629,7 @@
 		return n
 	}
 
-	l = new(NodeList)
+	l := new(NodeList)
 	l.N = n
 	l.Next = typecheckdefstack
 	typecheckdefstack = l
@@ -3729,7 +3637,7 @@
 	if n.Walkdef == 2 {
 		Flusherrors()
 		fmt.Printf("typecheckdef loop:")
-		for l = typecheckdefstack; l != nil; l = l.Next {
+		for l := typecheckdefstack; l != nil; l = l.Next {
 			fmt.Printf(" %v", Sconv(l.N.Sym, 0))
 		}
 		fmt.Printf("\n")
@@ -3762,7 +3670,7 @@
 			}
 		}
 
-		e = n.Defn
+		e := n.Defn
 		n.Defn = nil
 		if e == nil {
 			lineno = n.Lineno
@@ -3785,7 +3693,7 @@
 			goto ret
 		}
 
-		t = n.Type
+		t := n.Type
 		if t != nil {
 			if okforconst[t.Etype] == 0 {
 				Yyerror("invalid constant type %v", Tconv(t, 0))
@@ -3847,7 +3755,7 @@
 		n.Walkdef = 1
 		n.Type = typ(TFORW)
 		n.Type.Sym = n.Sym
-		nerrors0 = nerrors
+		nerrors0 := nerrors
 		typecheckdeftype(n)
 		if n.Type.Etype == TFORW && nerrors > nerrors0 {
 			// Something went wrong during type-checking,
@@ -3920,8 +3828,6 @@
 }
 
 func markbreak(n *Node, implicit *Node) {
-	var lab *Label
-
 	if n == nil {
 		return
 	}
@@ -3933,7 +3839,7 @@
 				implicit.Hasbreak = 1
 			}
 		} else {
-			lab = n.Left.Sym.Label
+			lab := n.Left.Sym.Label
 			if lab != nil {
 				lab.Def.Hasbreak = 1
 			}
@@ -3990,9 +3896,6 @@
 }
 
 func isterminating(l *NodeList, top int) bool {
-	var def int
-	var n *Node
-
 	if l == nil {
 		return false
 	}
@@ -4006,7 +3909,7 @@
 	for l.Next != nil {
 		l = l.Next
 	}
-	n = l.N
+	n := l.N
 
 	if n == nil {
 		return false
@@ -4046,7 +3949,7 @@
 		if n.Hasbreak != 0 {
 			return false
 		}
-		def = 0
+		def := 0
 		for l = n.List; l != nil; l = l.Next {
 			if !isterminating(l.N.Nbody, 0) {
 				return false
diff --git a/src/cmd/internal/gc/unsafe.go b/src/cmd/internal/gc/unsafe.go
index 3970468..7f0a33f 100644
--- a/src/cmd/internal/gc/unsafe.go
+++ b/src/cmd/internal/gc/unsafe.go
@@ -15,19 +15,11 @@
  */
 func unsafenmagic(nn *Node) *Node {
 	var r *Node
-	var n *Node
-	var base *Node
-	var r1 *Node
 	var s *Sym
-	var t *Type
-	var tr *Type
 	var v int64
-	var val Val
-	var fn *Node
-	var args *NodeList
 
-	fn = nn.Left
-	args = nn.List
+	fn := nn.Left
+	args := nn.List
 
 	if safemode != 0 || fn == nil || fn.Op != ONAME {
 		goto no
@@ -50,7 +42,7 @@
 	if s.Name == "Sizeof" {
 		typecheck(&r, Erv)
 		defaultlit(&r, nil)
-		tr = r.Type
+		tr := r.Type
 		if tr == nil {
 			goto bad
 		}
@@ -70,7 +62,7 @@
 		// first to track it correctly.
 		typecheck(&r.Left, Erv)
 
-		base = r.Left
+		base := r.Left
 		typecheck(&r, Erv)
 		switch r.Op {
 		case ODOT,
@@ -89,6 +81,7 @@
 		v = 0
 
 		// add offsets for inserted dots.
+		var r1 *Node
 		for r1 = r; r1.Left != base; r1 = r1.Left {
 			switch r1.Op {
 			case ODOT:
@@ -112,13 +105,13 @@
 	if s.Name == "Alignof" {
 		typecheck(&r, Erv)
 		defaultlit(&r, nil)
-		tr = r.Type
+		tr := r.Type
 		if tr == nil {
 			goto bad
 		}
 
 		// make struct { byte; T; }
-		t = typ(TSTRUCT)
+		t := typ(TSTRUCT)
 
 		t.Type = typ(TFIELD)
 		t.Type.Type = Types[TUINT8]
@@ -149,11 +142,12 @@
 
 	// any side effects disappear; ignore init
 ret:
+	var val Val
 	val.Ctype = CTINT
 
 	val.U.Xval = new(Mpint)
 	Mpmovecfix(val.U.Xval, v)
-	n = Nod(OLITERAL, nil, nil)
+	n := Nod(OLITERAL, nil, nil)
 	n.Orig = nn
 	n.Val = val
 	n.Type = Types[TUINTPTR]
diff --git a/src/cmd/internal/gc/walk.go b/src/cmd/internal/gc/walk.go
index dfb965e..b242fd4 100644
--- a/src/cmd/internal/gc/walk.go
+++ b/src/cmd/internal/gc/walk.go
@@ -18,35 +18,31 @@
 )
 
 func walk(fn *Node) {
-	var s string
-	var l *NodeList
-	var lno int
-
 	Curfn = fn
 
 	if Debug['W'] != 0 {
-		s = fmt.Sprintf("\nbefore %v", Sconv(Curfn.Nname.Sym, 0))
+		s := fmt.Sprintf("\nbefore %v", Sconv(Curfn.Nname.Sym, 0))
 		dumplist(s, Curfn.Nbody)
 	}
 
-	lno = int(lineno)
+	lno := int(lineno)
 
 	// Final typecheck for any unused variables.
 	// It's hard to be on the heap when not-used, but best to be consistent about &~PHEAP here and below.
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		if l.N.Op == ONAME && l.N.Class&^PHEAP == PAUTO {
 			typecheck(&l.N, Erv|Easgn)
 		}
 	}
 
 	// Propagate the used flag for typeswitch variables up to the NONAME in it's definition.
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		if l.N.Op == ONAME && l.N.Class&^PHEAP == PAUTO && l.N.Defn != nil && l.N.Defn.Op == OTYPESW && l.N.Used != 0 {
 			l.N.Defn.Left.Used++
 		}
 	}
 
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		if l.N.Op != ONAME || l.N.Class&^PHEAP != PAUTO || l.N.Sym.Name[0] == '&' || l.N.Used != 0 {
 			continue
 		}
@@ -69,13 +65,13 @@
 	}
 	walkstmtlist(Curfn.Nbody)
 	if Debug['W'] != 0 {
-		s = fmt.Sprintf("after walk %v", Sconv(Curfn.Nname.Sym, 0))
+		s := fmt.Sprintf("after walk %v", Sconv(Curfn.Nname.Sym, 0))
 		dumplist(s, Curfn.Nbody)
 	}
 
 	heapmoves()
 	if Debug['W'] != 0 && Curfn.Enter != nil {
-		s = fmt.Sprintf("enter %v", Sconv(Curfn.Nname.Sym, 0))
+		s := fmt.Sprintf("enter %v", Sconv(Curfn.Nname.Sym, 0))
 		dumplist(s, Curfn.Enter)
 	}
 }
@@ -96,9 +92,7 @@
 }
 
 func paramoutheap(fn *Node) int {
-	var l *NodeList
-
-	for l = fn.Dcl; l != nil; l = l.Next {
+	for l := fn.Dcl; l != nil; l = l.Next {
 		switch l.N.Class {
 		case PPARAMOUT,
 			PPARAMOUT | PHEAP:
@@ -117,13 +111,11 @@
 // adds "adjust" to all the argument locations for the call n.
 // n must be a defer or go node that has already been walked.
 func adjustargs(n *Node, adjust int) {
-	var callfunc *Node
 	var arg *Node
 	var lhs *Node
-	var args *NodeList
 
-	callfunc = n.Left
-	for args = callfunc.List; args != nil; args = args.Next {
+	callfunc := n.Left
+	for args := callfunc.List; args != nil; args = args.Next {
 		arg = args.N
 		if arg.Op != OAS {
 			Yyerror("call arg not assignment")
@@ -147,14 +139,7 @@
 }
 
 func walkstmt(np **Node) {
-	var init *NodeList
-	var ll *NodeList
-	var rl *NodeList
-	var cl int
-	var n *Node
-	var f *Node
-
-	n = *np
+	n := *np
 	if n == nil {
 		return
 	}
@@ -198,7 +183,7 @@
 		if n.Typecheck == 0 {
 			Fatal("missing typecheck: %v", Nconv(n, obj.FmtSign))
 		}
-		init = n.Ninit
+		init := n.Ninit
 		n.Ninit = nil
 		walkexpr(&n, &init)
 		addinit(&n, init)
@@ -212,7 +197,7 @@
 		if n.Typecheck == 0 {
 			Fatal("missing typecheck: %v", Nconv(n, obj.FmtSign))
 		}
-		init = n.Ninit
+		init := n.Ninit
 		n.Ninit = nil
 
 		walkexpr(&n.Left, &init)
@@ -264,7 +249,7 @@
 	case OFOR:
 		if n.Ntest != nil {
 			walkstmtlist(n.Ntest.Ninit)
-			init = n.Ntest.Ninit
+			init := n.Ntest.Ninit
 			n.Ntest.Ninit = nil
 			walkexpr(&n.Ntest, &init)
 			addinit(&n.Ntest, init)
@@ -302,9 +287,10 @@
 		if (Curfn.Type.Outnamed != 0 && count(n.List) > 1) || paramoutheap(Curfn) != 0 {
 			// assign to the function out parameters,
 			// so that reorder3 can fix up conflicts
-			rl = nil
+			rl := (*NodeList)(nil)
 
-			for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
+			var cl int
+			for ll := Curfn.Dcl; ll != nil; ll = ll.Next {
 				cl = int(ll.N.Class) &^ PHEAP
 				if cl == PAUTO {
 					break
@@ -323,7 +309,7 @@
 
 			if count(n.List) == 1 && count(rl) > 1 {
 				// OAS2FUNC in disguise
-				f = n.List.N
+				f := n.List.N
 
 				if f.Op != OCALLFUNC && f.Op != OCALLMETH && f.Op != OCALLINTER {
 					Fatal("expected return of call, have %v", Nconv(f, 0))
@@ -335,12 +321,12 @@
 			// move function calls out, to make reorder3's job easier.
 			walkexprlistsafe(n.List, &n.Ninit)
 
-			ll = ascompatee(int(n.Op), rl, n.List, &n.Ninit)
+			ll := ascompatee(int(n.Op), rl, n.List, &n.Ninit)
 			n.List = reorder3(ll)
 			break
 		}
 
-		ll = ascompatte(int(n.Op), nil, 0, Getoutarg(Curfn.Type), n.List, 1, &n.Ninit)
+		ll := ascompatte(int(n.Op), nil, 0, Getoutarg(Curfn.Type), n.List, 1, &n.Ninit)
 		n.List = ll
 
 	case ORETJMP:
@@ -395,31 +381,7 @@
 }
 
 func walkexpr(np **Node, init **NodeList) {
-	var r *Node
-	var l *Node
-	var var_ *Node
-	var a *Node
-	var ok *Node
-	var map_ *Node
-	var key *Node
-	var ll *NodeList
-	var lr *NodeList
-	var t *Type
-	var et int
-	var old_safemode int
-	var v int64
-	var lno int32
-	var n *Node
-	var fn *Node
-	var n1 *Node
-	var n2 *Node
-	var sym *Sym
-	var buf string
-	var p string
-	var from string
-	var to string
-
-	n = *np
+	n := *np
 
 	if n == nil {
 		return
@@ -445,7 +407,7 @@
 		return
 	}
 
-	lno = setlineno(n)
+	lno := setlineno(n)
 
 	if Debug['w'] > 1 {
 		Dump("walk-before", n)
@@ -515,7 +477,7 @@
 
 		// replace len(*[10]int) with 10.
 		// delayed until now to preserve side effects.
-		t = n.Left.Type
+		t := n.Left.Type
 
 		if Isptr[t.Etype] != 0 {
 			t = t.Type
@@ -532,7 +494,7 @@
 		ORSH:
 		walkexpr(&n.Left, init)
 		walkexpr(&n.Right, init)
-		t = n.Left.Type
+		t := n.Left.Type
 		n.Bounded = bounded(n.Right, 8*t.Width)
 		if Debug['m'] != 0 && n.Etype != 0 && !Isconst(n.Right, CTINT) {
 			Warn("shift bounds check elided")
@@ -576,7 +538,7 @@
 		// In this case it can happen if we need to generate an ==
 		// for a struct containing a reflect.Value, which itself has
 		// an unexported field of type unsafe.Pointer.
-		old_safemode = safemode
+		old_safemode := safemode
 
 		safemode = 0
 		walkcompare(&n, init)
@@ -590,7 +552,7 @@
 		// cannot put side effects from n->right on init,
 		// because they cannot run before n->left is checked.
 		// save elsewhere and store on the eventual n->right.
-		ll = nil
+		ll := (*NodeList)(nil)
 
 		walkexpr(&n.Right, &ll)
 		addinit(&n.Right, ll)
@@ -626,13 +588,13 @@
 		goto ret
 
 	case OCALLINTER:
-		t = n.Left.Type
+		t := n.Left.Type
 		if n.List != nil && n.List.N.Op == OAS {
 			goto ret
 		}
 		walkexpr(&n.Left, init)
 		walkexprlist(n.List, init)
-		ll = ascompatte(int(n.Op), n, int(n.Isddd), getinarg(t), n.List, 0, init)
+		ll := ascompatte(int(n.Op), n, int(n.Isddd), getinarg(t), n.List, 0, init)
 		n.List = reorder1(ll)
 		goto ret
 
@@ -652,7 +614,7 @@
 			// Update type of OCALLFUNC node.
 			// Output arguments had not changed, but their offsets could.
 			if n.Left.Type.Outtuple == 1 {
-				t = getoutargx(n.Left.Type).Type
+				t := getoutargx(n.Left.Type).Type
 				if t.Etype == TFIELD {
 					t = t.Type
 				}
@@ -662,7 +624,7 @@
 			}
 		}
 
-		t = n.Left.Type
+		t := n.Left.Type
 		if n.List != nil && n.List.N.Op == OAS {
 			goto ret
 		}
@@ -670,19 +632,19 @@
 		walkexpr(&n.Left, init)
 		walkexprlist(n.List, init)
 
-		ll = ascompatte(int(n.Op), n, int(n.Isddd), getinarg(t), n.List, 0, init)
+		ll := ascompatte(int(n.Op), n, int(n.Isddd), getinarg(t), n.List, 0, init)
 		n.List = reorder1(ll)
 		goto ret
 
 	case OCALLMETH:
-		t = n.Left.Type
+		t := n.Left.Type
 		if n.List != nil && n.List.N.Op == OAS {
 			goto ret
 		}
 		walkexpr(&n.Left, init)
 		walkexprlist(n.List, init)
-		ll = ascompatte(int(n.Op), n, 0, getthis(t), list1(n.Left.Left), 0, init)
-		lr = ascompatte(int(n.Op), n, int(n.Isddd), getinarg(t), n.List, 0, init)
+		ll := ascompatte(int(n.Op), n, 0, getthis(t), list1(n.Left.Left), 0, init)
+		lr := ascompatte(int(n.Op), n, int(n.Isddd), getinarg(t), n.List, 0, init)
 		ll = concat(ll, lr)
 		n.Left.Left = nil
 		ullmancalc(n.Left)
@@ -713,12 +675,12 @@
 		case ODOTTYPE:
 			walkexpr(&n.Right.Left, init)
 
-			n1 = Nod(OADDR, n.Left, nil)
-			r = n.Right // i.(T)
+			n1 := Nod(OADDR, n.Left, nil)
+			r := n.Right // i.(T)
 
-			from = "I"
+			from := "I"
 
-			to = "T"
+			to := "T"
 			if isnilinter(r.Left.Type) {
 				from = "E"
 			}
@@ -728,9 +690,9 @@
 				to = "I"
 			}
 
-			buf = fmt.Sprintf("assert%s2%s", from, to)
+			buf := fmt.Sprintf("assert%s2%s", from, to)
 
-			fn = syslook(buf, 1)
+			fn := syslook(buf, 1)
 			argtype(fn, r.Left.Type)
 			argtype(fn, r.Type)
 
@@ -743,15 +705,15 @@
 		case ORECV:
 			walkexpr(&n.Right.Left, init)
 
-			n1 = Nod(OADDR, n.Left, nil)
-			r = n.Right.Left // the channel
+			n1 := Nod(OADDR, n.Left, nil)
+			r := n.Right.Left // the channel
 			n = mkcall1(chanfn("chanrecv1", 2, r.Type), nil, init, typename(r.Type), r, n1)
 			walkexpr(&n, init)
 			goto ret
 		}
 
 		if n.Left != nil && n.Right != nil {
-			r = convas(Nod(OAS, n.Left, n.Right), init)
+			r := convas(Nod(OAS, n.Left, n.Right), init)
 			r.Dodata = n.Dodata
 			n = r
 			n = applywritebarrier(n, init)
@@ -764,9 +726,9 @@
 		n.Ninit = nil
 		walkexprlistsafe(n.List, init)
 		walkexprlistsafe(n.Rlist, init)
-		ll = ascompatee(OAS, n.List, n.Rlist, init)
+		ll := ascompatee(OAS, n.List, n.Rlist, init)
 		ll = reorder3(ll)
-		for lr = ll; lr != nil; lr = lr.Next {
+		for lr := ll; lr != nil; lr = lr.Next {
 			lr.N = applywritebarrier(lr.N, init)
 		}
 		n = liststmt(ll)
@@ -777,12 +739,12 @@
 		*init = concat(*init, n.Ninit)
 
 		n.Ninit = nil
-		r = n.Rlist.N
+		r := n.Rlist.N
 		walkexprlistsafe(n.List, init)
 		walkexpr(&r, init)
 
-		ll = ascompatet(int(n.Op), n.List, &r.Type, 0, init)
-		for lr = ll; lr != nil; lr = lr.Next {
+		ll := ascompatet(int(n.Op), n.List, &r.Type, 0, init)
+		for lr := ll; lr != nil; lr = lr.Next {
 			lr.N = applywritebarrier(lr.N, init)
 		}
 		n = liststmt(concat(list1(r), ll))
@@ -794,16 +756,17 @@
 		*init = concat(*init, n.Ninit)
 
 		n.Ninit = nil
-		r = n.Rlist.N
+		r := n.Rlist.N
 		walkexprlistsafe(n.List, init)
 		walkexpr(&r.Left, init)
+		var n1 *Node
 		if isblank(n.List.N) {
 			n1 = nodnil()
 		} else {
 			n1 = Nod(OADDR, n.List.N, nil)
 		}
 		n1.Etype = 1 // addr does not escape
-		fn = chanfn("chanrecv2", 2, r.Left.Type)
+		fn := chanfn("chanrecv2", 2, r.Left.Type)
 		r = mkcall1(fn, n.List.Next.N.Type, init, typename(r.Left.Type), r.Left, n1)
 		n = Nod(OAS, n.List.Next.N, r)
 		typecheck(&n, Etop)
@@ -814,12 +777,12 @@
 		*init = concat(*init, n.Ninit)
 
 		n.Ninit = nil
-		r = n.Rlist.N
+		r := n.Rlist.N
 		walkexprlistsafe(n.List, init)
 		walkexpr(&r.Left, init)
 		walkexpr(&r.Right, init)
-		t = r.Left.Type
-		p = ""
+		t := r.Left.Type
+		p := ""
 		if t.Type.Width <= 128 { // Check ../../runtime/hashmap.go:maxValueSize before changing.
 			switch Simsimtype(t.Down) {
 			case TINT32,
@@ -835,6 +798,7 @@
 			}
 		}
 
+		var key *Node
 		if p != "" {
 			// fast versions take key by value
 			key = r.Right
@@ -851,9 +815,9 @@
 		// to:
 		//   var,b = mapaccess2*(t, m, i)
 		//   a = *var
-		a = n.List.N
+		a := n.List.N
 
-		fn = mapfn(p, t)
+		fn := mapfn(p, t)
 		r = mkcall1(fn, getoutargx(fn.Type), init, typename(t), r.Left, key)
 
 		// mapaccess2* returns a typed bool, but due to spec changes,
@@ -867,7 +831,7 @@
 
 		// don't generate a = *var if a is _
 		if !isblank(a) {
-			var_ = temp(Ptrto(t.Type))
+			var_ := temp(Ptrto(t.Type))
 			var_.Typecheck = 1
 			n.List.N = var_
 			walkexpr(&n, init)
@@ -889,15 +853,15 @@
 	case ODELETE:
 		*init = concat(*init, n.Ninit)
 		n.Ninit = nil
-		map_ = n.List.N
-		key = n.List.Next.N
+		map_ := n.List.N
+		key := n.List.Next.N
 		walkexpr(&map_, init)
 		walkexpr(&key, init)
 
 		// orderstmt made sure key is addressable.
 		key = Nod(OADDR, key, nil)
 
-		t = map_.Type
+		t := map_.Type
 		n = mkcall1(mapfndel("mapdelete", t), nil, init, typename(t), map_, key)
 		goto ret
 
@@ -907,9 +871,10 @@
 		*init = concat(*init, n.Ninit)
 
 		n.Ninit = nil
-		r = n.Rlist.N
+		r := n.Rlist.N
 		walkexprlistsafe(n.List, init)
 		walkexpr(&r.Left, init)
+		var n1 *Node
 		if isblank(n.List.N) {
 			n1 = nodnil()
 		} else {
@@ -917,9 +882,9 @@
 		}
 		n1.Etype = 1 // addr does not escape
 
-		from = "I"
+		from := "I"
 
-		to = "T"
+		to := "T"
 		if isnilinter(r.Left.Type) {
 			from = "E"
 		}
@@ -928,14 +893,14 @@
 		} else if Isinter(r.Type) {
 			to = "I"
 		}
-		buf = fmt.Sprintf("assert%s2%s2", from, to)
+		buf := fmt.Sprintf("assert%s2%s2", from, to)
 
-		fn = syslook(buf, 1)
+		fn := syslook(buf, 1)
 		argtype(fn, r.Left.Type)
 		argtype(fn, r.Type)
 
-		t = Types[TBOOL]
-		ok = n.List.Next.N
+		t := Types[TBOOL]
+		ok := n.List.Next.N
 		if !isblank(ok) {
 			t = ok.Type
 		}
@@ -953,7 +918,7 @@
 
 		// Optimize convT2E as a two-word copy when T is pointer-shaped.
 		if isnilinter(n.Type) && isdirectiface(n.Left.Type) {
-			l = Nod(OEFACE, typename(n.Left.Type), n.Left)
+			l := Nod(OEFACE, typename(n.Left.Type), n.Left)
 			l.Type = n.Type
 			l.Typecheck = n.Typecheck
 			n = l
@@ -963,9 +928,9 @@
 		// Build name of function: convI2E etc.
 		// Not all names are possible
 		// (e.g., we'll never generate convE2E or convE2I).
-		from = "T"
+		from := "T"
 
-		to = "I"
+		to := "I"
 		if isnilinter(n.Left.Type) {
 			from = "E"
 		} else if Isinter(n.Left.Type) {
@@ -974,10 +939,10 @@
 		if isnilinter(n.Type) {
 			to = "E"
 		}
-		buf = fmt.Sprintf("conv%s2%s", from, to)
+		buf := fmt.Sprintf("conv%s2%s", from, to)
 
-		fn = syslook(buf, 1)
-		ll = nil
+		fn := syslook(buf, 1)
+		ll := (*NodeList)(nil)
 		if !Isinter(n.Left.Type) {
 			ll = list(ll, typename(n.Left.Type))
 		}
@@ -985,9 +950,9 @@
 			ll = list(ll, typename(n.Type))
 		}
 		if !Isinter(n.Left.Type) && !isnilinter(n.Type) {
-			sym = Pkglookup(fmt.Sprintf("%v.%v", Tconv(n.Left.Type, obj.FmtLeft), Tconv(n.Type, obj.FmtLeft)), itabpkg)
+			sym := Pkglookup(fmt.Sprintf("%v.%v", Tconv(n.Left.Type, obj.FmtLeft), Tconv(n.Type, obj.FmtLeft)), itabpkg)
 			if sym.Def == nil {
-				l = Nod(ONAME, nil, nil)
+				l := Nod(ONAME, nil, nil)
 				l.Sym = sym
 				l.Type = Ptrto(Types[TUINT8])
 				l.Addable = 1
@@ -997,7 +962,7 @@
 				ggloblsym(sym, int32(Widthptr), obj.DUPOK|obj.NOPTR)
 			}
 
-			l = Nod(OADDR, sym.Def, nil)
+			l := Nod(OADDR, sym.Def, nil)
 			l.Addable = 1
 			ll = list(ll, l)
 
@@ -1012,19 +977,19 @@
 				 * The CONVIFACE expression is replaced with this:
 				 * 	OEFACE{tab, ptr};
 				 */
-				l = temp(Ptrto(Types[TUINT8]))
+				l := temp(Ptrto(Types[TUINT8]))
 
-				n1 = Nod(OAS, l, sym.Def)
+				n1 := Nod(OAS, l, sym.Def)
 				typecheck(&n1, Etop)
 				*init = list(*init, n1)
 
-				fn = syslook("typ2Itab", 1)
+				fn := syslook("typ2Itab", 1)
 				n1 = Nod(OCALL, fn, nil)
 				n1.List = ll
 				typecheck(&n1, Erv)
 				walkexpr(&n1, init)
 
-				n2 = Nod(OIF, nil, nil)
+				n2 := Nod(OIF, nil, nil)
 				n2.Ntest = Nod(OEQ, l, nodnil())
 				n2.Nbody = list1(Nod(OAS, l, n1))
 				n2.Likely = -1
@@ -1117,10 +1082,10 @@
 		/*
 		 * rewrite complex div into function call.
 		 */
-		et = int(n.Left.Type.Etype)
+		et := int(n.Left.Type.Etype)
 
 		if Iscomplex[et] != 0 && n.Op == ODIV {
-			t = n.Type
+			t := n.Type
 			n = mkcall("complex128div", Types[TCOMPLEX128], init, conv(n.Left, Types[TCOMPLEX128]), conv(n.Right, Types[TCOMPLEX128]))
 			n = conv(n, t)
 			goto ret
@@ -1167,7 +1132,7 @@
 
 		// save the original node for bounds checking elision.
 		// If it was a ODIV/OMOD walk might rewrite it.
-		r = n.Right
+		r := n.Right
 
 		walkexpr(&n.Right, init)
 
@@ -1176,7 +1141,7 @@
 		if n.Bounded {
 			goto ret
 		}
-		t = n.Left.Type
+		t := n.Left.Type
 		if t != nil && Isptr[t.Etype] != 0 {
 			t = t.Type
 		}
@@ -1200,7 +1165,7 @@
 					// replace "abc"[1] with 'b'.
 					// delayed until now because "abc"[1] is not
 					// an ideal constant.
-					v = Mpgetfix(n.Right.Val.U.Xval)
+					v := Mpgetfix(n.Right.Val.U.Xval)
 
 					Nodconst(n, n.Type, int64(n.Left.Val.U.Sval.S[v]))
 					n.Typecheck = 1
@@ -1222,8 +1187,8 @@
 		walkexpr(&n.Left, init)
 		walkexpr(&n.Right, init)
 
-		t = n.Left.Type
-		p = ""
+		t := n.Left.Type
+		p := ""
 		if t.Type.Width <= 128 { // Check ../../runtime/hashmap.go:maxValueSize before changing.
 			switch Simsimtype(t.Down) {
 			case TINT32,
@@ -1239,6 +1204,7 @@
 			}
 		}
 
+		var key *Node
 		if p != "" {
 			// fast versions take key by value
 			key = n.Right
@@ -1325,7 +1291,7 @@
 
 	case ONEW:
 		if n.Esc == EscNone && n.Type.Type.Width < 1<<16 {
-			r = temp(n.Type.Type)
+			r := temp(n.Type.Type)
 			r = Nod(OAS, r, nil) // zero temp
 			typecheck(&r, Etop)
 			*init = list(*init, r)
@@ -1343,7 +1309,7 @@
 	// without the function call.
 	case OCMPSTR:
 		if (Isconst(n.Left, CTSTR) && len(n.Left.Val.U.Sval.S) == 0) || (Isconst(n.Right, CTSTR) && len(n.Right.Val.U.Sval.S) == 0) {
-			r = Nod(int(n.Etype), Nod(OLEN, n.Left, nil), Nod(OLEN, n.Right, nil))
+			r := Nod(int(n.Etype), Nod(OLEN, n.Left, nil), Nod(OLEN, n.Right, nil))
 			typecheck(&r, Erv)
 			walkexpr(&r, init)
 			r.Type = n.Type
@@ -1353,7 +1319,7 @@
 
 		// s + "badgerbadgerbadger" == "badgerbadgerbadger"
 		if (n.Etype == OEQ || n.Etype == ONE) && Isconst(n.Right, CTSTR) && n.Left.Op == OADDSTR && count(n.Left.List) == 2 && Isconst(n.Left.List.Next.N, CTSTR) && cmpslit(n.Right, n.Left.List.Next.N) == 0 {
-			r = Nod(int(n.Etype), Nod(OLEN, n.Left.List.N, nil), Nodintconst(0))
+			r := Nod(int(n.Etype), Nod(OLEN, n.Left.List.N, nil), Nodintconst(0))
 			typecheck(&r, Erv)
 			walkexpr(&r, init)
 			r.Type = n.Type
@@ -1361,6 +1327,7 @@
 			goto ret
 		}
 
+		var r *Node
 		if n.Etype == OEQ || n.Etype == ONE {
 			// prepare for rewrite below
 			n.Left = cheapexpr(n.Left, init)
@@ -1416,7 +1383,7 @@
 
 		// cannot use chanfn - closechan takes any, not chan any
 	case OCLOSE:
-		fn = syslook("closechan", 1)
+		fn := syslook("closechan", 1)
 
 		argtype(fn, n.Left.Type)
 		n = mkcall1(fn, nil, init, n.Left)
@@ -1427,15 +1394,15 @@
 		goto ret
 
 	case OMAKEMAP:
-		t = n.Type
+		t := n.Type
 
-		fn = syslook("makemap", 1)
+		fn := syslook("makemap", 1)
 
-		a = nodnil() // hmap buffer
-		r = nodnil() // bucket buffer
+		a := nodnil() // hmap buffer
+		r := nodnil() // bucket buffer
 		if n.Esc == EscNone {
 			// Allocate hmap buffer on stack.
-			var_ = temp(hmap(t))
+			var_ := temp(hmap(t))
 
 			a = Nod(OAS, var_, nil) // zero temp
 			typecheck(&a, Etop)
@@ -1461,29 +1428,29 @@
 		goto ret
 
 	case OMAKESLICE:
-		l = n.Left
-		r = n.Right
+		l := n.Left
+		r := n.Right
 		if r == nil {
 			r = safeexpr(l, init)
 			l = r
 		}
-		t = n.Type
+		t := n.Type
 		if n.Esc == EscNone && Smallintconst(l) && Smallintconst(r) && (t.Type.Width == 0 || Mpgetfix(r.Val.U.Xval) < (1<<16)/t.Type.Width) {
 			// var arr [r]T
 			// n = arr[:l]
 			t = aindex(r, t.Type) // [r]T
-			var_ = temp(t)
-			a = Nod(OAS, var_, nil) // zero temp
+			var_ := temp(t)
+			a := Nod(OAS, var_, nil) // zero temp
 			typecheck(&a, Etop)
 			*init = list(*init, a)
-			r = Nod(OSLICE, var_, Nod(OKEY, nil, l)) // arr[:l]
-			r = conv(r, n.Type)                      // in case n->type is named.
+			r := Nod(OSLICE, var_, Nod(OKEY, nil, l)) // arr[:l]
+			r = conv(r, n.Type)                       // in case n->type is named.
 			typecheck(&r, Erv)
 			walkexpr(&r, init)
 			n = r
 		} else {
 			// makeslice(t *Type, nel int64, max int64) (ary []any)
-			fn = syslook("makeslice", 1)
+			fn := syslook("makeslice", 1)
 
 			argtype(fn, t.Type) // any-1
 			n = mkcall1(fn, n.Type, init, typename(n.Type), conv(l, Types[TINT64]), conv(r, Types[TINT64]))
@@ -1492,10 +1459,10 @@
 		goto ret
 
 	case ORUNESTR:
-		a = nodnil()
+		a := nodnil()
 		if n.Esc == EscNone {
-			t = aindex(Nodintconst(4), Types[TUINT8])
-			var_ = temp(t)
+			t := aindex(Nodintconst(4), Types[TUINT8])
+			var_ := temp(t)
 			a = Nod(OADDR, var_, nil)
 		}
 
@@ -1505,10 +1472,10 @@
 		goto ret
 
 	case OARRAYBYTESTR:
-		a = nodnil()
+		a := nodnil()
 		if n.Esc == EscNone {
 			// Create temporary buffer for string on stack.
-			t = aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
 
 			a = Nod(OADDR, temp(t), nil)
 		}
@@ -1526,11 +1493,11 @@
 
 		// slicerunetostring(*[32]byte, []rune) string;
 	case OARRAYRUNESTR:
-		a = nodnil()
+		a := nodnil()
 
 		if n.Esc == EscNone {
 			// Create temporary buffer for string on stack.
-			t = aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
 
 			a = Nod(OADDR, temp(t), nil)
 		}
@@ -1540,11 +1507,11 @@
 
 		// stringtoslicebyte(*32[byte], string) []byte;
 	case OSTRARRAYBYTE:
-		a = nodnil()
+		a := nodnil()
 
 		if n.Esc == EscNone {
 			// Create temporary buffer for slice on stack.
-			t = aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
 
 			a = Nod(OADDR, temp(t), nil)
 		}
@@ -1560,11 +1527,11 @@
 
 		// stringtoslicerune(*[32]rune, string) []rune
 	case OSTRARRAYRUNE:
-		a = nodnil()
+		a := nodnil()
 
 		if n.Esc == EscNone {
 			// Create temporary buffer for slice on stack.
-			t = aindex(Nodintconst(tmpstringbufsize), Types[TINT32])
+			t := aindex(Nodintconst(tmpstringbufsize), Types[TINT32])
 
 			a = Nod(OADDR, temp(t), nil)
 		}
@@ -1577,6 +1544,7 @@
 		if !Eqtype(n.Left.Type, n.Right.Type) {
 			Fatal("ifaceeq %v %v %v", Oconv(int(n.Op), 0), Tconv(n.Left.Type, 0), Tconv(n.Right.Type, 0))
 		}
+		var fn *Node
 		if isnilinter(n.Left.Type) {
 			fn = syslook("efaceeq", 1)
 		} else {
@@ -1587,7 +1555,7 @@
 		n.Left = cheapexpr(n.Left, init)
 		argtype(fn, n.Right.Type)
 		argtype(fn, n.Left.Type)
-		r = mkcall1(fn, n.Type, init, n.Left, n.Right)
+		r := mkcall1(fn, n.Type, init, n.Left, n.Right)
 		if n.Etype == ONE {
 			r = Nod(ONOT, r, nil)
 		}
@@ -1608,13 +1576,13 @@
 		OMAPLIT,
 		OSTRUCTLIT,
 		OPTRLIT:
-		var_ = temp(n.Type)
+		var_ := temp(n.Type)
 		anylit(0, n, var_, init)
 		n = var_
 		goto ret
 
 	case OSEND:
-		n1 = n.Right
+		n1 := n.Right
 		n1 = assignconv(n1, n.Left.Type.Type, "chan send")
 		walkexpr(&n1, init)
 		n1 = Nod(OADDR, n1, nil)
@@ -1638,7 +1606,7 @@
 	// walk of y%1 may have replaced it by 0.
 	// Check whether n with its updated args is itself now a constant.
 ret:
-	t = n.Type
+	t := n.Type
 
 	evconst(n)
 	n.Type = t
@@ -1657,11 +1625,9 @@
 }
 
 func ascompatee1(op int, l *Node, r *Node, init **NodeList) *Node {
-	var n *Node
-
 	// convas will turn map assigns into function calls,
 	// making it impossible for reorder3 to work.
-	n = Nod(OAS, l, r)
+	n := Nod(OAS, l, r)
 
 	if l.Op == OINDEXMAP {
 		return n
@@ -1673,7 +1639,6 @@
 func ascompatee(op int, nl *NodeList, nr *NodeList, init **NodeList) *NodeList {
 	var ll *NodeList
 	var lr *NodeList
-	var nn *NodeList
 
 	/*
 	 * check assign expression list to
@@ -1689,7 +1654,7 @@
 		lr.N = safeexpr(lr.N, init)
 	}
 
-	nn = nil
+	nn := (*NodeList)(nil)
 	ll = nl
 	lr = nr
 	for ; ll != nil && lr != nil; (func() { ll = ll.Next; lr = lr.Next })() {
@@ -1714,12 +1679,10 @@
  * in the conversion of the types
  */
 func fncall(l *Node, rt *Type) bool {
-	var r Node
-
 	if l.Ullman >= UINF || l.Op == OINDEXMAP {
 		return true
 	}
-	r = Node{}
+	r := Node{}
 	if needwritebarrier(l, &r) {
 		return true
 	}
@@ -1734,22 +1697,18 @@
 	var tmp *Node
 	var a *Node
 	var ll *NodeList
-	var r *Type
 	var saver Iter
-	var ucount int
-	var nn *NodeList
-	var mm *NodeList
 
 	/*
 	 * check assign type list to
 	 * a expression list. called in
 	 *	expr-list = func()
 	 */
-	r = Structfirst(&saver, nr)
+	r := Structfirst(&saver, nr)
 
-	nn = nil
-	mm = nil
-	ucount = 0
+	nn := (*NodeList)(nil)
+	mm := (*NodeList)(nil)
+	ucount := 0
 	for ll = nl; ll != nil; ll = ll.Next {
 		if r == nil {
 			break
@@ -1798,20 +1757,16 @@
 * package all the arguments that match a ... T parameter into a []T.
  */
 func mkdotargslice(lr0 *NodeList, nn *NodeList, l *Type, fp int, init **NodeList, ddd *Node) *NodeList {
-	var a *Node
-	var n *Node
-	var tslice *Type
-	var esc int
-
-	esc = EscUnknown
+	esc := EscUnknown
 	if ddd != nil {
 		esc = int(ddd.Esc)
 	}
 
-	tslice = typ(TARRAY)
+	tslice := typ(TARRAY)
 	tslice.Type = l.Type.Type
 	tslice.Bound = -1
 
+	var n *Node
 	if count(lr0) == 0 {
 		n = nodnil()
 		n.Type = tslice
@@ -1829,7 +1784,7 @@
 		walkexpr(&n, init)
 	}
 
-	a = Nod(OAS, nodarg(l, fp), n)
+	a := Nod(OAS, nodarg(l, fp), n)
 	nn = list(nn, convas(a, init))
 	return nn
 }
@@ -1838,15 +1793,12 @@
  * helpers for shape errors
  */
 func dumptypes(nl **Type, what string) string {
-	var first int
-	var l *Type
 	var savel Iter
-	var fmt_ string
 
-	fmt_ = ""
+	fmt_ := ""
 	fmt_ += fmt.Sprintf("\t")
-	first = 1
-	for l = Structfirst(&savel, nl); l != nil; l = structnext(&savel) {
+	first := 1
+	for l := Structfirst(&savel, nl); l != nil; l = structnext(&savel) {
 		if first != 0 {
 			first = 0
 		} else {
@@ -1862,13 +1814,11 @@
 }
 
 func dumpnodetypes(l *NodeList, what string) string {
-	var first int
 	var r *Node
-	var fmt_ string
 
-	fmt_ = ""
+	fmt_ := ""
 	fmt_ += fmt.Sprintf("\t")
-	first = 1
+	first := 1
 	for ; l != nil; l = l.Next {
 		r = l.N
 		if first != 0 {
@@ -1892,30 +1842,25 @@
  *	func(expr-list)
  */
 func ascompatte(op int, call *Node, isddd int, nl **Type, lr *NodeList, fp int, init **NodeList) *NodeList {
-	var l *Type
-	var ll *Type
-	var r *Node
-	var a *Node
-	var nn *NodeList
-	var lr0 *NodeList
-	var alist *NodeList
 	var savel Iter
-	var l1 string
-	var l2 string
 
-	lr0 = lr
-	l = Structfirst(&savel, nl)
-	r = nil
+	lr0 := lr
+	l := Structfirst(&savel, nl)
+	r := (*Node)(nil)
 	if lr != nil {
 		r = lr.N
 	}
-	nn = nil
+	nn := (*NodeList)(nil)
 
 	// f(g()) where g has multiple return values
+	var a *Node
+	var l2 string
+	var ll *Type
+	var l1 string
 	if r != nil && lr.Next == nil && r.Type.Etype == TSTRUCT && r.Type.Funarg != 0 {
 		// optimization - can do block copy
 		if eqtypenoname(r.Type, *nl) {
-			a = nodarg(*nl, fp)
+			a := nodarg(*nl, fp)
 			r = Nod(OCONVNOP, r, nil)
 			r.Type = a.Type
 			nn = list1(convas(Nod(OAS, a, r), init))
@@ -1924,9 +1869,9 @@
 
 		// conversions involved.
 		// copy into temporaries.
-		alist = nil
+		alist := (*NodeList)(nil)
 
-		for l = Structfirst(&savel, &r.Type); l != nil; l = structnext(&savel) {
+		for l := Structfirst(&savel, &r.Type); l != nil; l = structnext(&savel) {
 			a = temp(l.Type)
 			alist = list(alist, a)
 		}
@@ -2007,26 +1952,21 @@
 func walkprint(nn *Node, init **NodeList) *Node {
 	var r *Node
 	var n *Node
-	var l *NodeList
-	var all *NodeList
 	var on *Node
 	var t *Type
-	var notfirst bool
 	var et int
-	var op int
-	var calls *NodeList
 
-	op = int(nn.Op)
-	all = nn.List
-	calls = nil
-	notfirst = false
+	op := int(nn.Op)
+	all := nn.List
+	calls := (*NodeList)(nil)
+	notfirst := false
 
 	// Hoist all the argument evaluation up before the lock.
 	walkexprlistcheap(all, init)
 
 	calls = list(calls, mkcall("printlock", nil, init))
 
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		if notfirst {
 			calls = list(calls, mkcall("printsp", nil, init))
 		}
@@ -2129,23 +2069,19 @@
 }
 
 func callnew(t *Type) *Node {
-	var fn *Node
-
 	dowidth(t)
-	fn = syslook("newobject", 1)
+	fn := syslook("newobject", 1)
 	argtype(fn, t)
 	return mkcall1(fn, Ptrto(t), nil, typename(t))
 }
 
 func isstack(n *Node) bool {
-	var defn *Node
-
 	n = outervalue(n)
 
 	// If n is *autotmp and autotmp = &foo, replace n with foo.
 	// We introduce such temps when initializing struct literals.
 	if n.Op == OIND && n.Left.Op == ONAME && strings.HasPrefix(n.Left.Sym.Name, "autotmp_") {
-		defn = n.Left.Defn
+		defn := n.Left.Defn
 		if defn != nil && defn.Op == OAS && defn.Right.Op == OADDR {
 			n = defn.Right.Left
 		}
@@ -2263,18 +2199,12 @@
 var applywritebarrier_bv *Bvec
 
 func applywritebarrier(n *Node, init **NodeList) *Node {
-	var l *Node
-	var r *Node
-	var t *Type
-	var x int64
-	var name string
-
 	if n.Left != nil && n.Right != nil && needwritebarrier(n.Left, n.Right) {
 		if Curfn != nil && Curfn.Nowritebarrier {
 			Yyerror("write barrier prohibited")
 		}
-		t = n.Left.Type
-		l = Nod(OADDR, n.Left, nil)
+		t := n.Left.Type
+		l := Nod(OADDR, n.Left, nil)
 		l.Etype = 1 // addr does not escape
 		if t.Width == int64(Widthptr) {
 			n = mkcall1(writebarrierfn("writebarrierptr", t, n.Right.Type), nil, init, l, n.Right)
@@ -2285,7 +2215,7 @@
 		} else if Isinter(t) {
 			n = mkcall1(writebarrierfn("writebarrieriface", t, n.Right.Type), nil, init, l, n.Right)
 		} else if t.Width <= int64(4*Widthptr) {
-			x = 0
+			x := int64(0)
 			if applywritebarrier_bv == nil {
 				applywritebarrier_bv = bvalloc(obj.BitsPerPointer * 4)
 			}
@@ -2298,6 +2228,7 @@
 			if obj.BitsPointer != 1<<PtrBit {
 				Fatal("wrong PtrBit")
 			}
+			var name string
 			switch t.Width / int64(Widthptr) {
 			default:
 				Fatal("found writebarrierfat for %d-byte object of type %v", int(t.Width), Tconv(t, 0))
@@ -2314,7 +2245,7 @@
 
 			n = mkcall1(writebarrierfn(name, t, n.Right.Type), nil, init, l, nodnil(), n.Right)
 		} else {
-			r = n.Right
+			r := n.Right
 			for r.Op == OCONVNOP {
 				r = r.Left
 			}
@@ -2330,18 +2261,14 @@
 }
 
 func convas(n *Node, init **NodeList) *Node {
-	var lt *Type
-	var rt *Type
-	var map_ *Node
-	var key *Node
-	var val *Node
-
 	if n.Op != OAS {
 		Fatal("convas: not OAS %v", Oconv(int(n.Op), 0))
 	}
 
 	n.Typecheck = 1
 
+	var lt *Type
+	var rt *Type
 	if n.Left == nil || n.Right == nil {
 		goto out
 	}
@@ -2358,9 +2285,9 @@
 	}
 
 	if n.Left.Op == OINDEXMAP {
-		map_ = n.Left.Left
-		key = n.Left.Right
-		val = n.Right
+		map_ := n.Left.Left
+		key := n.Left.Right
+		val := n.Right
 		walkexpr(&map_, init)
 		walkexpr(&key, init)
 		walkexpr(&val, init)
@@ -2392,20 +2319,12 @@
  * make temp variables
  */
 func reorder1(all *NodeList) *NodeList {
-	var f *Node
-	var a *Node
 	var n *Node
-	var l *NodeList
-	var r *NodeList
-	var g *NodeList
-	var c int
-	var d int
-	var t int
 
-	c = 0 // function calls
-	t = 0 // total parameters
+	c := 0 // function calls
+	t := 0 // total parameters
 
-	for l = all; l != nil; l = l.Next {
+	for l := all; l != nil; l = l.Next {
 		n = l.N
 		t++
 		ullmancalc(n)
@@ -2418,11 +2337,12 @@
 		return all
 	}
 
-	g = nil // fncalls assigned to tempnames
-	f = nil // last fncall assigned to stack
-	r = nil // non fncalls and tempnames assigned to stack
-	d = 0
-	for l = all; l != nil; l = l.Next {
+	g := (*NodeList)(nil) // fncalls assigned to tempnames
+	f := (*Node)(nil)     // last fncall assigned to stack
+	r := (*NodeList)(nil) // non fncalls and tempnames assigned to stack
+	d := 0
+	var a *Node
+	for l := all; l != nil; l = l.Next {
 		n = l.N
 		if n.Ullman < UINF {
 			r = list(r, n)
@@ -2463,18 +2383,15 @@
  * function calls have been removed.
  */
 func reorder3(all *NodeList) *NodeList {
-	var list *NodeList
-	var early *NodeList
-	var mapinit *NodeList
 	var l *Node
 
 	// If a needed expression may be affected by an
 	// earlier assignment, make an early copy of that
 	// expression and use the copy instead.
-	early = nil
+	early := (*NodeList)(nil)
 
-	mapinit = nil
-	for list = all; list != nil; list = list.Next {
+	mapinit := (*NodeList)(nil)
+	for list := all; list != nil; list = list.Next {
 		l = list.N.Left
 
 		// Save subexpressions needed on left side.
@@ -2529,15 +2446,12 @@
  * replace *np with that temp.
  */
 func reorder3save(np **Node, all *NodeList, stop *NodeList, early **NodeList) {
-	var n *Node
-	var q *Node
-
-	n = *np
+	n := *np
 	if !aliased(n, all, stop) {
 		return
 	}
 
-	q = temp(n.Type)
+	q := temp(n.Type)
 	q = Nod(OAS, q, n)
 	typecheck(&q, Etop)
 	*early = list(*early, q)
@@ -2574,11 +2488,6 @@
  * affected by writes in as up to but not including stop?
  */
 func aliased(n *Node, all *NodeList, stop *NodeList) bool {
-	var memwrite int
-	var varwrite int
-	var a *Node
-	var l *NodeList
-
 	if n == nil {
 		return false
 	}
@@ -2588,10 +2497,11 @@
 	// Also record whether there are any writes to main memory.
 	// Also record whether there are any writes to variables
 	// whose addresses have been taken.
-	memwrite = 0
+	memwrite := 0
 
-	varwrite = 0
-	for l = all; l != stop; l = l.Next {
+	varwrite := 0
+	var a *Node
+	for l := all; l != stop; l = l.Next {
 		a = outervalue(l.N.Left)
 		if a.Op != ONAME {
 			memwrite = 1
@@ -2698,8 +2608,6 @@
  * is the name l mentioned in r?
  */
 func vmatch2(l *Node, r *Node) bool {
-	var ll *NodeList
-
 	if r == nil {
 		return false
 	}
@@ -2718,7 +2626,7 @@
 	if vmatch2(l, r.Right) {
 		return true
 	}
-	for ll = r.List; ll != nil; ll = ll.Next {
+	for ll := r.List; ll != nil; ll = ll.Next {
 		if vmatch2(l, ll.N) {
 			return true
 		}
@@ -2731,8 +2639,6 @@
  * called by sinit.c
  */
 func vmatch1(l *Node, r *Node) bool {
-	var ll *NodeList
-
 	/*
 	 * isolate all left sides
 	 */
@@ -2767,7 +2673,7 @@
 	if vmatch1(l.Right, r) {
 		return true
 	}
-	for ll = l.List; ll != nil; ll = ll.Next {
+	for ll := l.List; ll != nil; ll = ll.Next {
 		if vmatch1(ll.N, r) {
 			return true
 		}
@@ -2781,14 +2687,12 @@
  * copies of escaped parameters to the heap.
  */
 func paramstoheap(argin **Type, out int) *NodeList {
-	var t *Type
 	var savet Iter
 	var v *Node
 	var as *Node
-	var nn *NodeList
 
-	nn = nil
-	for t = Structfirst(&savet, argin); t != nil; t = structnext(&savet) {
+	nn := (*NodeList)(nil)
+	for t := Structfirst(&savet, argin); t != nil; t = structnext(&savet) {
 		v = t.Nname
 		if v != nil && v.Sym != nil && v.Sym.Name[0] == '~' && v.Sym.Name[1] == 'r' { // unnamed result
 			v = nil
@@ -2831,13 +2735,11 @@
  * walk through argout parameters copying back to stack
  */
 func returnsfromheap(argin **Type) *NodeList {
-	var t *Type
 	var savet Iter
 	var v *Node
-	var nn *NodeList
 
-	nn = nil
-	for t = Structfirst(&savet, argin); t != nil; t = structnext(&savet) {
+	nn := (*NodeList)(nil)
+	for t := Structfirst(&savet, argin); t != nil; t = structnext(&savet) {
 		v = t.Nname
 		if v == nil || v.Class != PHEAP|PPARAMOUT {
 			continue
@@ -2854,12 +2756,9 @@
  * curfn's before and after lists.
  */
 func heapmoves() {
-	var nn *NodeList
-	var lno int32
-
-	lno = lineno
+	lno := lineno
 	lineno = Curfn.Lineno
-	nn = paramstoheap(getthis(Curfn.Type), 0)
+	nn := paramstoheap(getthis(Curfn.Type), 0)
 	nn = concat(nn, paramstoheap(getinarg(Curfn.Type), 0))
 	nn = concat(nn, paramstoheap(Getoutarg(Curfn.Type), 1))
 	Curfn.Enter = concat(Curfn.Enter, nn)
@@ -2869,22 +2768,17 @@
 }
 
 func vmkcall(fn *Node, t *Type, init **NodeList, va []*Node) *Node {
-	var i int
-	var n int
-	var r *Node
-	var args *NodeList
-
 	if fn.Type == nil || fn.Type.Etype != TFUNC {
 		Fatal("mkcall %v %v", Nconv(fn, 0), Tconv(fn.Type, 0))
 	}
 
-	args = nil
-	n = fn.Type.Intuple
-	for i = 0; i < n; i++ {
+	args := (*NodeList)(nil)
+	n := fn.Type.Intuple
+	for i := 0; i < n; i++ {
 		args = list(args, va[i])
 	}
 
-	r = Nod(OCALL, fn, nil)
+	r := Nod(OCALL, fn, nil)
 	r.List = args
 	if fn.Type.Outtuple > 0 {
 		typecheck(&r, Erv|Efnstruct)
@@ -2915,26 +2809,21 @@
 }
 
 func chanfn(name string, n int, t *Type) *Node {
-	var fn *Node
-	var i int
-
 	if t.Etype != TCHAN {
 		Fatal("chanfn %v", Tconv(t, 0))
 	}
-	fn = syslook(name, 1)
-	for i = 0; i < n; i++ {
+	fn := syslook(name, 1)
+	for i := 0; i < n; i++ {
 		argtype(fn, t.Type)
 	}
 	return fn
 }
 
 func mapfn(name string, t *Type) *Node {
-	var fn *Node
-
 	if t.Etype != TMAP {
 		Fatal("mapfn %v", Tconv(t, 0))
 	}
-	fn = syslook(name, 1)
+	fn := syslook(name, 1)
 	argtype(fn, t.Down)
 	argtype(fn, t.Type)
 	argtype(fn, t.Down)
@@ -2943,12 +2832,10 @@
 }
 
 func mapfndel(name string, t *Type) *Node {
-	var fn *Node
-
 	if t.Etype != TMAP {
 		Fatal("mapfn %v", Tconv(t, 0))
 	}
-	fn = syslook(name, 1)
+	fn := syslook(name, 1)
 	argtype(fn, t.Down)
 	argtype(fn, t.Type)
 	argtype(fn, t.Down)
@@ -2956,36 +2843,24 @@
 }
 
 func writebarrierfn(name string, l *Type, r *Type) *Node {
-	var fn *Node
-
-	fn = syslook(name, 1)
+	fn := syslook(name, 1)
 	argtype(fn, l)
 	argtype(fn, r)
 	return fn
 }
 
 func addstr(n *Node, init **NodeList) *Node {
-	var r *Node
-	var cat *Node
-	var slice *Node
-	var buf *Node
-	var args *NodeList
-	var l *NodeList
-	var c int
-	var sz int64
-	var t *Type
-
 	// orderexpr rewrote OADDSTR to have a list of strings.
-	c = count(n.List)
+	c := count(n.List)
 
 	if c < 2 {
 		Yyerror("addstr count %d too small", c)
 	}
 
-	buf = nodnil()
+	buf := nodnil()
 	if n.Esc == EscNone {
-		sz = 0
-		for l = n.List; l != nil; l = l.Next {
+		sz := int64(0)
+		for l := n.List; l != nil; l = l.Next {
 			if n.Op == OLITERAL {
 				sz += int64(len(n.Val.U.Sval.S))
 			}
@@ -2994,16 +2869,16 @@
 		// Don't allocate the buffer if the result won't fit.
 		if sz < tmpstringbufsize {
 			// Create temporary buffer for result string on stack.
-			t = aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
+			t := aindex(Nodintconst(tmpstringbufsize), Types[TUINT8])
 
 			buf = Nod(OADDR, temp(t), nil)
 		}
 	}
 
 	// build list of string arguments
-	args = list1(buf)
+	args := list1(buf)
 
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		args = list(args, conv(l.N, Types[TSTRING]))
 	}
 
@@ -3015,10 +2890,10 @@
 		// large numbers of strings are passed to the runtime as a slice.
 		namebuf = "concatstrings"
 
-		t = typ(TARRAY)
+		t := typ(TARRAY)
 		t.Type = Types[TSTRING]
 		t.Bound = -1
-		slice = Nod(OCOMPLIT, nil, typenod(t))
+		slice := Nod(OCOMPLIT, nil, typenod(t))
 		slice.Alloc = n.Alloc
 		slice.List = args.Next // skip buf arg
 		args = list1(buf)
@@ -3026,8 +2901,8 @@
 		slice.Esc = EscNone
 	}
 
-	cat = syslook(namebuf, 1)
-	r = Nod(OCALL, cat, nil)
+	cat := syslook(namebuf, 1)
+	r := Nod(OCALL, cat, nil)
 	r.List = args
 	typecheck(&r, Erv)
 	walkexpr(&r, init)
@@ -3049,36 +2924,25 @@
 //
 // l2 is allowed to be a string.
 func appendslice(n *Node, init **NodeList) *Node {
-	var l *NodeList
-	var l1 *Node
-	var l2 *Node
-	var nt *Node
-	var nif *Node
-	var fn *Node
-	var nptr1 *Node
-	var nptr2 *Node
-	var nwid *Node
-	var s *Node
-
 	walkexprlistsafe(n.List, init)
 
 	// walkexprlistsafe will leave OINDEX (s[n]) alone if both s
 	// and n are name or literal, but those may index the slice we're
 	// modifying here.  Fix explicitly.
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		l.N = cheapexpr(l.N, init)
 	}
 
-	l1 = n.List.N
-	l2 = n.List.Next.N
+	l1 := n.List.N
+	l2 := n.List.Next.N
 
-	s = temp(l1.Type) // var s []T
-	l = nil
+	s := temp(l1.Type) // var s []T
+	l := (*NodeList)(nil)
 	l = list(l, Nod(OAS, s, l1)) // s = l1
 
-	nt = temp(Types[TINT])
+	nt := temp(Types[TINT])
 
-	nif = Nod(OIF, nil, nil)
+	nif := Nod(OIF, nil, nil)
 
 	// n := len(s) + len(l2) - cap(s)
 	nif.Ninit = list1(Nod(OAS, nt, Nod(OSUB, Nod(OADD, Nod(OLEN, s, nil), Nod(OLEN, l2, nil)), Nod(OCAP, s, nil))))
@@ -3086,7 +2950,7 @@
 	nif.Ntest = Nod(OGT, nt, Nodintconst(0))
 
 	// instantiate growslice(Type*, []any, int64) []any
-	fn = syslook("growslice", 1)
+	fn := syslook("growslice", 1)
 
 	argtype(fn, s.Type.Type)
 	argtype(fn, s.Type.Type)
@@ -3098,22 +2962,23 @@
 
 	if haspointers(l1.Type.Type) {
 		// copy(s[len(l1):len(l1)+len(l2)], l2)
-		nptr1 = Nod(OSLICE, s, Nod(OKEY, Nod(OLEN, l1, nil), Nod(OADD, Nod(OLEN, l1, nil), Nod(OLEN, l2, nil))))
+		nptr1 := Nod(OSLICE, s, Nod(OKEY, Nod(OLEN, l1, nil), Nod(OADD, Nod(OLEN, l1, nil), Nod(OLEN, l2, nil))))
 
 		nptr1.Etype = 1
-		nptr2 = l2
-		fn = syslook("typedslicecopy", 1)
+		nptr2 := l2
+		fn := syslook("typedslicecopy", 1)
 		argtype(fn, l1.Type)
 		argtype(fn, l2.Type)
-		nt = mkcall1(fn, Types[TINT], &l, typename(l1.Type.Type), nptr1, nptr2)
+		nt := mkcall1(fn, Types[TINT], &l, typename(l1.Type.Type), nptr1, nptr2)
 		l = list(l, nt)
 	} else if flag_race != 0 {
 		// rely on runtime to instrument copy.
 		// copy(s[len(l1):len(l1)+len(l2)], l2)
-		nptr1 = Nod(OSLICE, s, Nod(OKEY, Nod(OLEN, l1, nil), Nod(OADD, Nod(OLEN, l1, nil), Nod(OLEN, l2, nil))))
+		nptr1 := Nod(OSLICE, s, Nod(OKEY, Nod(OLEN, l1, nil), Nod(OADD, Nod(OLEN, l1, nil), Nod(OLEN, l2, nil))))
 
 		nptr1.Etype = 1
-		nptr2 = l2
+		nptr2 := l2
+		var fn *Node
 		if l2.Type.Etype == TSTRING {
 			fn = syslook("slicestringcopy", 1)
 		} else {
@@ -3121,25 +2986,25 @@
 		}
 		argtype(fn, l1.Type)
 		argtype(fn, l2.Type)
-		nt = mkcall1(fn, Types[TINT], &l, nptr1, nptr2, Nodintconst(s.Type.Type.Width))
+		nt := mkcall1(fn, Types[TINT], &l, nptr1, nptr2, Nodintconst(s.Type.Type.Width))
 		l = list(l, nt)
 	} else {
 		// memmove(&s[len(l1)], &l2[0], len(l2)*sizeof(T))
-		nptr1 = Nod(OINDEX, s, Nod(OLEN, l1, nil))
+		nptr1 := Nod(OINDEX, s, Nod(OLEN, l1, nil))
 
 		nptr1.Bounded = true
 		nptr1 = Nod(OADDR, nptr1, nil)
 
-		nptr2 = Nod(OSPTR, l2, nil)
+		nptr2 := Nod(OSPTR, l2, nil)
 
-		fn = syslook("memmove", 1)
+		fn := syslook("memmove", 1)
 		argtype(fn, s.Type.Type) // 1 old []any
 		argtype(fn, s.Type.Type) // 2 ret []any
 
-		nwid = cheapexpr(conv(Nod(OLEN, l2, nil), Types[TUINTPTR]), &l)
+		nwid := cheapexpr(conv(Nod(OLEN, l2, nil), Types[TUINTPTR]), &l)
 
 		nwid = Nod(OMUL, nwid, Nodintconst(s.Type.Type.Width))
-		nt = mkcall1(fn, nil, &l, nptr1, nptr2, nwid)
+		nt := mkcall1(fn, nil, &l, nptr1, nptr2, nwid)
 		l = list(l, nt)
 	}
 
@@ -3172,61 +3037,51 @@
 //   }
 //   s
 func walkappend(n *Node, init **NodeList) *Node {
-	var l *NodeList
-	var a *NodeList
-	var nsrc *Node
-	var ns *Node
-	var nn *Node
-	var na *Node
-	var nx *Node
-	var fn *Node
-	var argc int
-
 	walkexprlistsafe(n.List, init)
 
 	// walkexprlistsafe will leave OINDEX (s[n]) alone if both s
 	// and n are name or literal, but those may index the slice we're
 	// modifying here.  Fix explicitly.
-	for l = n.List; l != nil; l = l.Next {
+	for l := n.List; l != nil; l = l.Next {
 		l.N = cheapexpr(l.N, init)
 	}
 
-	nsrc = n.List.N
+	nsrc := n.List.N
 
 	// Resolve slice type of multi-valued return.
 	if Istype(nsrc.Type, TSTRUCT) {
 		nsrc.Type = nsrc.Type.Type.Type
 	}
-	argc = count(n.List) - 1
+	argc := count(n.List) - 1
 	if argc < 1 {
 		return nsrc
 	}
 
-	l = nil
+	l := (*NodeList)(nil)
 
-	ns = temp(nsrc.Type)
+	ns := temp(nsrc.Type)
 	l = list(l, Nod(OAS, ns, nsrc)) // s = src
 
-	na = Nodintconst(int64(argc)) // const argc
-	nx = Nod(OIF, nil, nil)       // if cap(s) - len(s) < argc
+	na := Nodintconst(int64(argc)) // const argc
+	nx := Nod(OIF, nil, nil)       // if cap(s) - len(s) < argc
 	nx.Ntest = Nod(OLT, Nod(OSUB, Nod(OCAP, ns, nil), Nod(OLEN, ns, nil)), na)
 
-	fn = syslook("growslice", 1) //   growslice(<type>, old []T, n int64) (ret []T)
-	argtype(fn, ns.Type.Type)    // 1 old []any
-	argtype(fn, ns.Type.Type)    // 2 ret []any
+	fn := syslook("growslice", 1) //   growslice(<type>, old []T, n int64) (ret []T)
+	argtype(fn, ns.Type.Type)     // 1 old []any
+	argtype(fn, ns.Type.Type)     // 2 ret []any
 
 	nx.Nbody = list1(Nod(OAS, ns, mkcall1(fn, ns.Type, &nx.Ninit, typename(ns.Type), ns, conv(na, Types[TINT64]))))
 
 	l = list(l, nx)
 
-	nn = temp(Types[TINT])
+	nn := temp(Types[TINT])
 	l = list(l, Nod(OAS, nn, Nod(OLEN, ns, nil))) // n = len(s)
 
 	nx = Nod(OSLICE, ns, Nod(OKEY, nil, Nod(OADD, nn, na))) // ...s[:n+argc]
 	nx.Etype = 1
 	l = list(l, Nod(OAS, ns, nx)) // s = s[:n+argc]
 
-	for a = n.List.Next; a != nil; a = a.Next {
+	for a := n.List.Next; a != nil; a = a.Next {
 		nx = Nod(OINDEX, ns, nn) // s[n] ...
 		nx.Bounded = true
 		l = list(l, Nod(OAS, nx, a.N)) // s[n] = arg
@@ -3253,22 +3108,13 @@
 // Also works if b is a string.
 //
 func copyany(n *Node, init **NodeList, runtimecall int) *Node {
-	var nl *Node
-	var nr *Node
-	var nfrm *Node
-	var nto *Node
-	var nif *Node
-	var nlen *Node
-	var nwid *Node
-	var fn *Node
-	var l *NodeList
-
 	if haspointers(n.Left.Type.Type) {
-		fn = writebarrierfn("typedslicecopy", n.Left.Type, n.Right.Type)
+		fn := writebarrierfn("typedslicecopy", n.Left.Type, n.Right.Type)
 		return mkcall1(fn, n.Type, init, typename(n.Left.Type.Type), n.Left, n.Right)
 	}
 
 	if runtimecall != 0 {
+		var fn *Node
 		if n.Right.Type.Etype == TSTRING {
 			fn = syslook("slicestringcopy", 1)
 		} else {
@@ -3281,33 +3127,33 @@
 
 	walkexpr(&n.Left, init)
 	walkexpr(&n.Right, init)
-	nl = temp(n.Left.Type)
-	nr = temp(n.Right.Type)
-	l = nil
+	nl := temp(n.Left.Type)
+	nr := temp(n.Right.Type)
+	l := (*NodeList)(nil)
 	l = list(l, Nod(OAS, nl, n.Left))
 	l = list(l, Nod(OAS, nr, n.Right))
 
-	nfrm = Nod(OSPTR, nr, nil)
-	nto = Nod(OSPTR, nl, nil)
+	nfrm := Nod(OSPTR, nr, nil)
+	nto := Nod(OSPTR, nl, nil)
 
-	nlen = temp(Types[TINT])
+	nlen := temp(Types[TINT])
 
 	// n = len(to)
 	l = list(l, Nod(OAS, nlen, Nod(OLEN, nl, nil)))
 
 	// if n > len(frm) { n = len(frm) }
-	nif = Nod(OIF, nil, nil)
+	nif := Nod(OIF, nil, nil)
 
 	nif.Ntest = Nod(OGT, nlen, Nod(OLEN, nr, nil))
 	nif.Nbody = list(nif.Nbody, Nod(OAS, nlen, Nod(OLEN, nr, nil)))
 	l = list(l, nif)
 
 	// Call memmove.
-	fn = syslook("memmove", 1)
+	fn := syslook("memmove", 1)
 
 	argtype(fn, nl.Type.Type)
 	argtype(fn, nl.Type.Type)
-	nwid = temp(Types[TUINTPTR])
+	nwid := temp(Types[TUINTPTR])
 	l = list(l, Nod(OAS, nwid, conv(nlen, Types[TUINTPTR])))
 	nwid = Nod(OMUL, nwid, Nodintconst(nl.Type.Type.Width))
 	l = list(l, mkcall1(fn, nil, init, nto, nfrm, nwid))
@@ -3321,30 +3167,15 @@
 // Generate frontend part for OSLICE[3][ARR|STR]
 //
 func sliceany(n *Node, init **NodeList) *Node {
-	var bounded int
-	var slice3 bool
-	var src *Node
-	var lb *Node
 	var hb *Node
 	var cb *Node
-	var bound *Node
-	var chk *Node
-	var chk0 *Node
-	var chk1 *Node
-	var chk2 *Node
-	var lbv int64
-	var hbv int64
-	var cbv int64
-	var bv int64
-	var w int64
-	var bt *Type
 
 	//	print("before sliceany: %+N\n", n);
 
-	src = n.Left
+	src := n.Left
 
-	lb = n.Right.Left
-	slice3 = n.Op == OSLICE3 || n.Op == OSLICE3ARR
+	lb := n.Right.Left
+	slice3 := n.Op == OSLICE3 || n.Op == OSLICE3ARR
 	if slice3 {
 		hb = n.Right.Right.Left
 		cb = n.Right.Right.Right
@@ -3353,8 +3184,9 @@
 		cb = nil
 	}
 
-	bounded = int(n.Etype)
+	bounded := int(n.Etype)
 
+	var bound *Node
 	if n.Op == OSLICESTR {
 		bound = Nod(OLEN, src, nil)
 	} else {
@@ -3365,7 +3197,7 @@
 	walkexpr(&bound, init) // if src is an array, bound will be a const now.
 
 	// static checks if possible
-	bv = 1 << 50
+	bv := int64(1 << 50)
 
 	if Isconst(bound, CTINT) {
 		if !Smallintconst(bound) {
@@ -3376,21 +3208,21 @@
 	}
 
 	if Isconst(cb, CTINT) {
-		cbv = Mpgetfix(cb.Val.U.Xval)
+		cbv := Mpgetfix(cb.Val.U.Xval)
 		if cbv < 0 || cbv > bv {
 			Yyerror("slice index out of bounds")
 		}
 	}
 
 	if Isconst(hb, CTINT) {
-		hbv = Mpgetfix(hb.Val.U.Xval)
+		hbv := Mpgetfix(hb.Val.U.Xval)
 		if hbv < 0 || hbv > bv {
 			Yyerror("slice index out of bounds")
 		}
 	}
 
 	if Isconst(lb, CTINT) {
-		lbv = Mpgetfix(lb.Val.U.Xval)
+		lbv := Mpgetfix(lb.Val.U.Xval)
 		if lbv < 0 || lbv > bv {
 			Yyerror("slice index out of bounds")
 			lbv = -1
@@ -3403,14 +3235,12 @@
 
 	// Checking src[lb:hb:cb] or src[lb:hb].
 	// if chk0 || chk1 || chk2 { panicslice() }
-	chk = nil
-
-	chk0 = nil // cap(src) < cb
-	chk1 = nil // cb < hb for src[lb:hb:cb]; cap(src) < hb for src[lb:hb]
-	chk2 = nil // hb < lb
+	chk0 := (*Node)(nil) // cap(src) < cb
+	chk1 := (*Node)(nil) // cb < hb for src[lb:hb:cb]; cap(src) < hb for src[lb:hb]
+	chk2 := (*Node)(nil) // hb < lb
 
 	// All comparisons are unsigned to avoid testing < 0.
-	bt = Types[Simtype[TUINT]]
+	bt := Types[Simtype[TUINT]]
 
 	if cb != nil && cb.Type.Width > 4 {
 		bt = Types[TUINT64]
@@ -3463,7 +3293,7 @@
 	}
 
 	if chk0 != nil || chk1 != nil || chk2 != nil {
-		chk = Nod(OIF, nil, nil)
+		chk := Nod(OIF, nil, nil)
 		chk.Nbody = list1(mkcall("panicslice", nil, init))
 		chk.Likely = -1
 		if chk0 != nil {
@@ -3521,6 +3351,7 @@
 
 	// offs = [width *] lo, but omit if zero
 	if lb != nil {
+		var w int64
 		if n.Op == OSLICESTR {
 			w = 1
 		} else {
@@ -3541,33 +3372,28 @@
 }
 
 func eqfor(t *Type, needsize *int) *Node {
-	var a int
-	var n *Node
-	var ntype *Node
-	var sym *Sym
-
 	// Should only arrive here with large memory or
 	// a struct/array containing a non-memory field/element.
 	// Small memory is handled inline, and single non-memory
 	// is handled during type check (OCMPSTR etc).
-	a = algtype1(t, nil)
+	a := algtype1(t, nil)
 
 	if a != AMEM && a != -1 {
 		Fatal("eqfor %v", Tconv(t, 0))
 	}
 
 	if a == AMEM {
-		n = syslook("memequal", 1)
+		n := syslook("memequal", 1)
 		argtype(n, t)
 		argtype(n, t)
 		*needsize = 1
 		return n
 	}
 
-	sym = typesymprefix(".eq", t)
-	n = newname(sym)
+	sym := typesymprefix(".eq", t)
+	n := newname(sym)
 	n.Class = PFUNC
-	ntype = Nod(OTFUNC, nil, nil)
+	ntype := Nod(OTFUNC, nil, nil)
 	ntype.List = list(ntype.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
 	ntype.List = list(ntype.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
 	ntype.Rlist = list(ntype.Rlist, Nod(ODCLFIELD, nil, typenod(Types[TBOOL])))
@@ -3578,36 +3404,15 @@
 }
 
 func countfield(t *Type) int {
-	var t1 *Type
-	var n int
-
-	n = 0
-	for t1 = t.Type; t1 != nil; t1 = t1.Down {
+	n := 0
+	for t1 := t.Type; t1 != nil; t1 = t1.Down {
 		n++
 	}
 	return n
 }
 
 func walkcompare(np **Node, init **NodeList) {
-	var n *Node
-	var l *Node
-	var r *Node
-	var call *Node
-	var a *Node
-	var li *Node
-	var ri *Node
-	var expr *Node
-	var cmpl *Node
-	var cmpr *Node
-	var x *Node
-	var ok *Node
-	var andor int
-	var i int
-	var needsize int
-	var t *Type
-	var t1 *Type
-
-	n = *np
+	n := *np
 
 	// Given interface value l and concrete value r, rewrite
 	//   l == r
@@ -3616,9 +3421,9 @@
 	// Handle != similarly.
 	// This avoids the allocation that would be required
 	// to convert r to l for comparison.
-	l = nil
+	l := (*Node)(nil)
 
-	r = nil
+	r := (*Node)(nil)
 	if Isinter(n.Left.Type) && !Isinter(n.Right.Type) {
 		l = n.Left
 		r = n.Right
@@ -3627,17 +3432,25 @@
 		r = n.Left
 	}
 
+	var call *Node
+	var a *Node
+	var cmpl *Node
+	var cmpr *Node
+	var andor int
+	var expr *Node
+	var needsize int
+	var t *Type
 	if l != nil {
-		x = temp(r.Type)
-		ok = temp(Types[TBOOL])
+		x := temp(r.Type)
+		ok := temp(Types[TBOOL])
 
 		// l.(type(r))
-		a = Nod(ODOTTYPE, l, nil)
+		a := Nod(ODOTTYPE, l, nil)
 
 		a.Type = r.Type
 
 		// x, ok := l.(type(r))
-		expr = Nod(OAS2, nil, nil)
+		expr := Nod(OAS2, nil, nil)
 
 		expr.List = list1(x)
 		expr.List = list(expr.List, ok)
@@ -3705,7 +3518,9 @@
 	if t.Etype == TARRAY && t.Bound <= 4 && issimple[t.Type.Etype] != 0 {
 		// Four or fewer elements of a basic type.
 		// Unroll comparisons.
-		for i = 0; int64(i) < t.Bound; i++ {
+		var li *Node
+		var ri *Node
+		for i := 0; int64(i) < t.Bound; i++ {
 			li = Nod(OINDEX, l, Nodintconst(int64(i)))
 			ri = Nod(OINDEX, r, Nodintconst(int64(i)))
 			a = Nod(int(n.Op), li, ri)
@@ -3726,7 +3541,9 @@
 	if t.Etype == TSTRUCT && countfield(t) <= 4 {
 		// Struct of four or fewer fields.
 		// Inline comparisons.
-		for t1 = t.Type; t1 != nil; t1 = t1.Down {
+		var li *Node
+		var ri *Node
+		for t1 := t.Type; t1 != nil; t1 = t1.Down {
 			if isblanksym(t1.Sym) {
 				continue
 			}
@@ -3809,24 +3626,16 @@
 }
 
 func walkrotate(np **Node) {
-	var w int
-	var sl int
-	var sr int
-	var s int
-	var l *Node
-	var r *Node
-	var n *Node
-
 	if Thearch.Thechar == '9' {
 		return
 	}
 
-	n = *np
+	n := *np
 
 	// Want << | >> or >> | << or << ^ >> or >> ^ << on unsigned value.
-	l = n.Left
+	l := n.Left
 
-	r = n.Right
+	r := n.Right
 	if (n.Op != OOR && n.Op != OXOR) || (l.Op != OLSH && l.Op != ORSH) || (r.Op != OLSH && r.Op != ORSH) || n.Type == nil || Issigned[n.Type.Etype] != 0 || l.Op == r.Op {
 		return
 	}
@@ -3837,12 +3646,12 @@
 	}
 
 	// Constants adding to width?
-	w = int(l.Type.Width * 8)
+	w := int(l.Type.Width * 8)
 
 	if Smallintconst(l.Right) && Smallintconst(r.Right) {
-		sl = int(Mpgetfix(l.Right.Val.U.Xval))
+		sl := int(Mpgetfix(l.Right.Val.U.Xval))
 		if sl >= 0 {
-			sr = int(Mpgetfix(r.Right.Val.U.Xval))
+			sr := int(Mpgetfix(r.Right.Val.U.Xval))
 			if sr >= 0 && sl+sr == w {
 				goto yes
 			}
@@ -3863,7 +3672,7 @@
 	n.Op = OLROT
 
 	// Remove rotate 0 and rotate w.
-	s = int(Mpgetfix(n.Right.Val.U.Xval))
+	s := int(Mpgetfix(n.Right.Val.U.Xval))
 
 	if s == 0 || s == w {
 		n = n.Left
@@ -3877,18 +3686,13 @@
  * walkmul rewrites integer multiplication by powers of two as shifts.
  */
 func walkmul(np **Node, init **NodeList) {
-	var n *Node
-	var nl *Node
-	var nr *Node
-	var pow int
-	var neg int
-	var w int
-
-	n = *np
+	n := *np
 	if Isint[n.Type.Etype] == 0 {
 		return
 	}
 
+	var nr *Node
+	var nl *Node
 	if n.Right.Op == OLITERAL {
 		nl = n.Left
 		nr = n.Right
@@ -3899,9 +3703,11 @@
 		return
 	}
 
-	neg = 0
+	neg := 0
 
 	// x*0 is 0 (and side effects of x).
+	var pow int
+	var w int
 	if Mpgetfix(nr.Val.U.Xval) == 0 {
 		cheapexpr(nl, init)
 		Nodconst(n, n.Type, 0)
@@ -3952,42 +3758,29 @@
  * operations.
  */
 func walkdiv(np **Node, init **NodeList) {
-	var n *Node
-	var nl *Node
-	var nr *Node
 	// if >= 0, nr is 1<<pow // 1 if nr is negative.
-	var nc *Node
-	var n1 *Node
-	var n2 *Node
-	var n3 *Node
-	var n4 *Node
-	var pow int
-	var s int
-	var w int
-	var twide *Type
-	var m Magic
 
 	// TODO(minux)
 	if Thearch.Thechar == '9' {
 		return
 	}
 
-	n = *np
+	n := *np
 	if n.Right.Op != OLITERAL {
 		return
 	}
 
 	// nr is a constant.
-	nl = cheapexpr(n.Left, init)
+	nl := cheapexpr(n.Left, init)
 
-	nr = n.Right
+	nr := n.Right
 
 	// special cases of mod/div
 	// by a constant
-	w = int(nl.Type.Width * 8)
+	w := int(nl.Type.Width * 8)
 
-	s = 0
-	pow = powtwo(nr)
+	s := 0
+	pow := powtwo(nr)
 	if pow >= 1000 {
 		// negative power of 2
 		s = 1
@@ -4000,6 +3793,9 @@
 		return
 	}
 
+	var n1 *Node
+	var m Magic
+	var n2 *Node
 	if pow < 0 {
 		goto divbymul
 	}
@@ -4025,32 +3821,32 @@
 				// signed modulo 2^pow is like ANDing
 				// with the last pow bits, but if nl < 0,
 				// nl & (2^pow-1) is (nl+1)%2^pow - 1.
-				nc = Nod(OXXX, nil, nil)
+				nc := Nod(OXXX, nil, nil)
 
 				Nodconst(nc, Types[Simtype[TUINT]], int64(w)-1)
-				n1 = Nod(ORSH, nl, nc) // n1 = -1 iff nl < 0.
+				n1 := Nod(ORSH, nl, nc) // n1 = -1 iff nl < 0.
 				if pow == 1 {
 					typecheck(&n1, Erv)
 					n1 = cheapexpr(n1, init)
 
 					// n = (nl+ε)&1 -ε where ε=1 iff nl<0.
-					n2 = Nod(OSUB, nl, n1)
+					n2 := Nod(OSUB, nl, n1)
 
-					nc = Nod(OXXX, nil, nil)
+					nc := Nod(OXXX, nil, nil)
 					Nodconst(nc, nl.Type, 1)
-					n3 = Nod(OAND, n2, nc)
+					n3 := Nod(OAND, n2, nc)
 					n = Nod(OADD, n3, n1)
 				} else {
 					// n = (nl+ε)&(nr-1) - ε where ε=2^pow-1 iff nl<0.
-					nc = Nod(OXXX, nil, nil)
+					nc := Nod(OXXX, nil, nil)
 
 					Nodconst(nc, nl.Type, (1<<uint(pow))-1)
-					n2 = Nod(OAND, n1, nc) // n2 = 2^pow-1 iff nl<0.
+					n2 := Nod(OAND, n1, nc) // n2 = 2^pow-1 iff nl<0.
 					typecheck(&n2, Erv)
 					n2 = cheapexpr(n2, init)
 
-					n3 = Nod(OADD, nl, n2)
-					n4 = Nod(OAND, n3, nc)
+					n3 := Nod(OADD, nl, n2)
+					n4 := Nod(OAND, n3, nc)
 					n = Nod(OSUB, n4, n2)
 				}
 
@@ -4059,19 +3855,19 @@
 				// arithmetic right shift does not give the correct rounding.
 				// if nl >= 0, nl >> n == nl / nr
 				// if nl < 0, we want to add 2^n-1 first.
-				nc = Nod(OXXX, nil, nil)
+				nc := Nod(OXXX, nil, nil)
 
 				Nodconst(nc, Types[Simtype[TUINT]], int64(w)-1)
-				n1 = Nod(ORSH, nl, nc) // n1 = -1 iff nl < 0.
+				n1 := Nod(ORSH, nl, nc) // n1 = -1 iff nl < 0.
 				if pow == 1 {
 					// nl+1 is nl-(-1)
 					n.Left = Nod(OSUB, nl, n1)
 				} else {
 					// Do a logical right right on -1 to keep pow bits.
-					nc = Nod(OXXX, nil, nil)
+					nc := Nod(OXXX, nil, nil)
 
 					Nodconst(nc, Types[Simtype[TUINT]], int64(w)-int64(pow))
-					n2 = Nod(ORSH, conv(n1, tounsigned(nl.Type)), nc)
+					n2 := Nod(ORSH, conv(n1, tounsigned(nl.Type)), nc)
 					n.Left = Nod(OADD, nl, conv(n2, nl.Type))
 				}
 
@@ -4090,7 +3886,7 @@
 			break
 		}
 
-		nc = Nod(OXXX, nil, nil)
+		nc := Nod(OXXX, nil, nil)
 		if n.Op == OMOD {
 			// n = nl & (nr-1)
 			n.Op = OAND
@@ -4141,14 +3937,15 @@
 	case TUINT8,
 		TUINT16,
 		TUINT32:
-		nc = Nod(OXXX, nil, nil)
+		nc := Nod(OXXX, nil, nil)
 
 		Nodconst(nc, nl.Type, int64(m.Um))
-		n1 = Nod(OMUL, nl, nc)
+		n1 := Nod(OMUL, nl, nc)
 		typecheck(&n1, Erv)
 		n1.Op = OHMUL
 		if m.Ua != 0 {
 			// Select a Go type with (at least) twice the width.
+			var twide *Type
 			switch Simtype[nl.Type.Etype] {
 			default:
 				return
@@ -4170,16 +3967,16 @@
 
 			// add numerator (might overflow).
 			// n2 = (n1 + nl)
-			n2 = Nod(OADD, conv(n1, twide), conv(nl, twide))
+			n2 := Nod(OADD, conv(n1, twide), conv(nl, twide))
 
 			// shift by m.s
-			nc = Nod(OXXX, nil, nil)
+			nc := Nod(OXXX, nil, nil)
 
 			Nodconst(nc, Types[TUINT], int64(m.S))
 			n = conv(Nod(ORSH, n2, nc), nl.Type)
 		} else {
 			// n = n1 >> m.s
-			nc = Nod(OXXX, nil, nil)
+			nc := Nod(OXXX, nil, nil)
 
 			Nodconst(nc, Types[TUINT], int64(m.S))
 			n = Nod(ORSH, n1, nc)
@@ -4189,10 +3986,10 @@
 	case TINT8,
 		TINT16,
 		TINT32:
-		nc = Nod(OXXX, nil, nil)
+		nc := Nod(OXXX, nil, nil)
 
 		Nodconst(nc, nl.Type, m.Sm)
-		n1 = Nod(OMUL, nl, nc)
+		n1 := Nod(OMUL, nl, nc)
 		typecheck(&n1, Erv)
 		n1.Op = OHMUL
 		if m.Sm < 0 {
@@ -4204,13 +4001,13 @@
 		nc = Nod(OXXX, nil, nil)
 
 		Nodconst(nc, Types[TUINT], int64(m.S))
-		n2 = conv(Nod(ORSH, n1, nc), nl.Type)
+		n2 := conv(Nod(ORSH, n1, nc), nl.Type)
 
 		// add 1 iff n1 is negative.
 		nc = Nod(OXXX, nil, nil)
 
 		Nodconst(nc, Types[TUINT], int64(w)-1)
-		n3 = Nod(ORSH, nl, nc) // n4 = -1 iff n1 is negative.
+		n3 := Nod(ORSH, nl, nc) // n4 = -1 iff n1 is negative.
 		n = Nod(OSUB, n2, n3)
 
 		// apply sign.
@@ -4237,25 +4034,21 @@
 
 // return 1 if integer n must be in range [0, max), 0 otherwise
 func bounded(n *Node, max int64) bool {
-	var v int64
-	var bits int32
-	var sign int
-
 	if n.Type == nil || Isint[n.Type.Etype] == 0 {
 		return false
 	}
 
-	sign = int(Issigned[n.Type.Etype])
-	bits = int32(8 * n.Type.Width)
+	sign := int(Issigned[n.Type.Etype])
+	bits := int32(8 * n.Type.Width)
 
 	if Smallintconst(n) {
-		v = Mpgetfix(n.Val.U.Xval)
+		v := Mpgetfix(n.Val.U.Xval)
 		return 0 <= v && v < max
 	}
 
 	switch n.Op {
 	case OAND:
-		v = -1
+		v := int64(-1)
 		if Smallintconst(n.Left) {
 			v = Mpgetfix(n.Left.Val.U.Xval)
 		} else if Smallintconst(n.Right) {
@@ -4268,7 +4061,7 @@
 
 	case OMOD:
 		if sign == 0 && Smallintconst(n.Right) {
-			v = Mpgetfix(n.Right.Val.U.Xval)
+			v := Mpgetfix(n.Right.Val.U.Xval)
 			if 0 <= v && v <= max {
 				return true
 			}
@@ -4276,7 +4069,7 @@
 
 	case ODIV:
 		if sign == 0 && Smallintconst(n.Right) {
-			v = Mpgetfix(n.Right.Val.U.Xval)
+			v := Mpgetfix(n.Right.Val.U.Xval)
 			for bits > 0 && v >= 2 {
 				bits--
 				v >>= 1
@@ -4285,7 +4078,7 @@
 
 	case ORSH:
 		if sign == 0 && Smallintconst(n.Right) {
-			v = Mpgetfix(n.Right.Val.U.Xval)
+			v := Mpgetfix(n.Right.Val.U.Xval)
 			if v > int64(bits) {
 				return true
 			}
@@ -4301,9 +4094,6 @@
 }
 
 func usefield(n *Node) {
-	var field *Type
-	var l *Type
-
 	if obj.Fieldtrack_enabled == 0 {
 		return
 	}
@@ -4317,7 +4107,7 @@
 		break
 	}
 
-	field = n.Paramfld
+	field := n.Paramfld
 	if field == nil {
 		Fatal("usefield %v %v without paramfld", Tconv(n.Left.Type, 0), Sconv(n.Right.Sym, 0))
 	}
@@ -4341,7 +4131,7 @@
 		Yyerror("tracked field must be exported (upper case)")
 	}
 
-	l = typ(0)
+	l := typ(0)
 	l.Type = field
 	l.Down = Curfn.Paramfld
 	Curfn.Paramfld = l
@@ -4462,17 +4252,7 @@
 var walkprintfunc_prgen int
 
 func walkprintfunc(np **Node, init **NodeList) {
-	var n *Node
-	var a *Node
-	var fn *Node
-	var t *Node
-	var oldfn *Node
-	var l *NodeList
-	var printargs *NodeList
-	var num int
-	var buf string
-
-	n = *np
+	n := *np
 
 	if n.Ninit != nil {
 		walkstmtlist(n.Ninit)
@@ -4480,10 +4260,12 @@
 		n.Ninit = nil
 	}
 
-	t = Nod(OTFUNC, nil, nil)
-	num = 0
-	printargs = nil
-	for l = n.List; l != nil; l = l.Next {
+	t := Nod(OTFUNC, nil, nil)
+	num := 0
+	printargs := (*NodeList)(nil)
+	var a *Node
+	var buf string
+	for l := n.List; l != nil; l = l.Next {
 		buf = fmt.Sprintf("a%d", num)
 		num++
 		a = Nod(ODCLFIELD, newname(Lookup(buf)), typenod(l.N.Type))
@@ -4491,7 +4273,7 @@
 		printargs = list(printargs, a.Left)
 	}
 
-	fn = Nod(ODCLFUNC, nil, nil)
+	fn := Nod(ODCLFUNC, nil, nil)
 	walkprintfunc_prgen++
 	buf = fmt.Sprintf("print·%d", walkprintfunc_prgen)
 	fn.Nname = newname(Lookup(buf))
@@ -4499,7 +4281,7 @@
 	fn.Nname.Ntype = t
 	declare(fn.Nname, PFUNC)
 
-	oldfn = Curfn
+	oldfn := Curfn
 	Curfn = nil
 	funchdr(fn)