cmd/compile: rewrite code to omit many nodeSeq calls

This CL was automatically generated using a special-purpose AST
rewriting tool, followed by manual editing to put some comments back in
the right places and fix some bad line breaks.

The result is not perfect but it's a big step toward getting back to
sanity, and because it was automatically generated there is a decent
chance that it is correct.

Passes toolstash -cmp.

Update #14473.

Change-Id: I01c09078a6d78e2b008bc304d744b79469a38d3d
Reviewed-on: https://go-review.googlesource.com/20440
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/cmd/compile/internal/gc/alg.go b/src/cmd/compile/internal/gc/alg.go
index f14e758f..2913d61 100644
--- a/src/cmd/compile/internal/gc/alg.go
+++ b/src/cmd/compile/internal/gc/alg.go
@@ -185,13 +185,13 @@
 	fn.Func.Nname.Name.Param.Ntype = tfn
 
 	n := Nod(ODCLFIELD, newname(Lookup("p")), typenod(Ptrto(t)))
-	appendNodeSeqNode(&tfn.List, n)
+	tfn.List.Append(n)
 	np := n.Left
 	n = Nod(ODCLFIELD, newname(Lookup("h")), typenod(Types[TUINTPTR]))
-	appendNodeSeqNode(&tfn.List, n)
+	tfn.List.Append(n)
 	nh := n.Left
 	n = Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])) // return value
-	appendNodeSeqNode(&tfn.Rlist, n)
+	tfn.Rlist.Append(n)
 
 	funchdr(fn)
 	typecheck(&fn.Func.Nname.Name.Param.Ntype, Etype)
@@ -216,10 +216,10 @@
 		n := Nod(ORANGE, nil, Nod(OIND, np, nil))
 		ni := newname(Lookup("i"))
 		ni.Type = Types[TINT]
-		setNodeSeq(&n.List, []*Node{ni})
+		n.List.Set([]*Node{ni})
 		n.Colas = true
 		colasdefn(n.List, n)
-		ni = nodeSeqFirst(n.List)
+		ni = n.List.First()
 
 		// h = hashel(&p[i], h)
 		call := Nod(OCALL, hashel, nil)
@@ -228,8 +228,8 @@
 		nx.Bounded = true
 		na := Nod(OADDR, nx, nil)
 		na.Etype = 1 // no escape to heap
-		appendNodeSeqNode(&call.List, na)
-		appendNodeSeqNode(&call.List, nh)
+		call.List.Append(na)
+		call.List.Append(nh)
 		n.Nbody.Append(Nod(OAS, nh, call))
 
 		fn.Nbody.Append(n)
@@ -251,8 +251,8 @@
 				nx := Nod(OXDOT, np, newname(f.Sym)) // TODO: fields from other packages?
 				na := Nod(OADDR, nx, nil)
 				na.Etype = 1 // no escape to heap
-				appendNodeSeqNode(&call.List, na)
-				appendNodeSeqNode(&call.List, nh)
+				call.List.Append(na)
+				call.List.Append(nh)
 				fn.Nbody.Append(Nod(OAS, nh, call))
 				f = f.Down
 				continue
@@ -267,9 +267,9 @@
 			nx := Nod(OXDOT, np, newname(f.Sym)) // TODO: fields from other packages?
 			na := Nod(OADDR, nx, nil)
 			na.Etype = 1 // no escape to heap
-			appendNodeSeqNode(&call.List, na)
-			appendNodeSeqNode(&call.List, nh)
-			appendNodeSeqNode(&call.List, Nodintconst(size))
+			call.List.Append(na)
+			call.List.Append(nh)
+			call.List.Append(Nodintconst(size))
 			fn.Nbody.Append(Nod(OAS, nh, call))
 
 			f = next
@@ -277,7 +277,7 @@
 	}
 
 	r := Nod(ORETURN, nil, nil)
-	appendNodeSeqNode(&r.List, nh)
+	r.List.Append(nh)
 	fn.Nbody.Append(r)
 
 	if Debug['r'] != 0 {
@@ -339,9 +339,9 @@
 	n := newname(sym)
 	n.Class = PFUNC
 	tfn := Nod(OTFUNC, nil, nil)
-	appendNodeSeqNode(&tfn.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
-	appendNodeSeqNode(&tfn.List, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
-	appendNodeSeqNode(&tfn.Rlist, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
+	tfn.List.Append(Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
+	tfn.List.Append(Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
+	tfn.Rlist.Append(Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
 	typecheck(&tfn, Etype)
 	n.Type = tfn.Type
 	return n
@@ -367,13 +367,13 @@
 	fn.Func.Nname.Name.Param.Ntype = tfn
 
 	n := Nod(ODCLFIELD, newname(Lookup("p")), typenod(Ptrto(t)))
-	appendNodeSeqNode(&tfn.List, n)
+	tfn.List.Append(n)
 	np := n.Left
 	n = Nod(ODCLFIELD, newname(Lookup("q")), typenod(Ptrto(t)))
-	appendNodeSeqNode(&tfn.List, n)
+	tfn.List.Append(n)
 	nq := n.Left
 	n = Nod(ODCLFIELD, nil, typenod(Types[TBOOL]))
-	appendNodeSeqNode(&tfn.Rlist, n)
+	tfn.Rlist.Append(n)
 
 	funchdr(fn)
 
@@ -398,10 +398,10 @@
 
 		ni := newname(Lookup("i"))
 		ni.Type = Types[TINT]
-		setNodeSeq(&nrange.List, []*Node{ni})
+		nrange.List.Set([]*Node{ni})
 		nrange.Colas = true
 		colasdefn(nrange.List, nrange)
-		ni = nodeSeqFirst(nrange.List)
+		ni = nrange.List.First()
 
 		// if p[i] != q[i] { return false }
 		nx := Nod(OINDEX, np, ni)
@@ -413,14 +413,14 @@
 		nif := Nod(OIF, nil, nil)
 		nif.Left = Nod(ONE, nx, ny)
 		r := Nod(ORETURN, nil, nil)
-		appendNodeSeqNode(&r.List, Nodbool(false))
+		r.List.Append(Nodbool(false))
 		nif.Nbody.Append(r)
 		nrange.Nbody.Append(nif)
 		fn.Nbody.Append(nrange)
 
 		// return true
 		ret := Nod(ORETURN, nil, nil)
-		appendNodeSeqNode(&ret.List, Nodbool(true))
+		ret.List.Append(Nodbool(true))
 		fn.Nbody.Append(ret)
 
 	case TSTRUCT:
@@ -474,7 +474,7 @@
 		}
 
 		ret := Nod(ORETURN, nil, nil)
-		appendNodeSeqNode(&ret.List, and)
+		ret.List.Append(and)
 		fn.Nbody.Append(ret)
 	}
 
@@ -531,10 +531,10 @@
 	typecheck(&ny, Erv)
 
 	call := Nod(OCALL, eqmemfunc(size, nx.Type.Type, &needsize), nil)
-	appendNodeSeqNode(&call.List, nx)
-	appendNodeSeqNode(&call.List, ny)
+	call.List.Append(nx)
+	call.List.Append(ny)
 	if needsize != 0 {
-		appendNodeSeqNode(&call.List, Nodintconst(size))
+		call.List.Append(Nodintconst(size))
 	}
 
 	return call
diff --git a/src/cmd/compile/internal/gc/bexport.go b/src/cmd/compile/internal/gc/bexport.go
index d0bb56a..97ce543 100644
--- a/src/cmd/compile/internal/gc/bexport.go
+++ b/src/cmd/compile/internal/gc/bexport.go
@@ -848,7 +848,7 @@
 
 	// expressions
 	case OMAKEMAP, OMAKECHAN, OMAKESLICE:
-		if p.bool(nodeSeqLen(n.List) != 0) {
+		if p.bool(n.List.Len() != 0) {
 			p.nodeList(n.List) // TODO(gri) do we still need to export this?
 		}
 		p.nodesOrNil(n.Left, n.Right)
@@ -970,7 +970,7 @@
 		p.nodeList(n.Nbody)
 
 	case ORANGE:
-		if p.bool(nodeSeqLen(n.List) != 0) {
+		if p.bool(n.List.Len() != 0) {
 			p.nodeList(n.List)
 		}
 		p.node(n.Right)
@@ -982,7 +982,7 @@
 		p.nodeList(n.List)
 
 	case OCASE, OXCASE:
-		if p.bool(nodeSeqLen(n.List) != 0) {
+		if p.bool(n.List.Len() != 0) {
 			p.nodeList(n.List)
 		}
 		p.nodeList(n.Nbody)
diff --git a/src/cmd/compile/internal/gc/bimport.go b/src/cmd/compile/internal/gc/bimport.go
index 16993d0..ac4c4b1 100644
--- a/src/cmd/compile/internal/gc/bimport.go
+++ b/src/cmd/compile/internal/gc/bimport.go
@@ -589,7 +589,7 @@
 	// expressions
 	case OMAKEMAP, OMAKECHAN, OMAKESLICE:
 		if p.bool() {
-			setNodeSeq(&n.List, p.nodeList())
+			n.List.Set(p.nodeList())
 		}
 		n.Left, n.Right = p.nodesOrNil()
 		n.Type = p.typ()
@@ -604,19 +604,19 @@
 		n.Right = p.node()
 
 	case OADDSTR:
-		setNodeSeq(&n.List, p.nodeList())
+		n.List.Set(p.nodeList())
 
 	case OPTRLIT:
 		n.Left = p.node()
 
 	case OSTRUCTLIT:
 		n.Type = p.typ()
-		setNodeSeq(&n.List, p.nodeList())
+		n.List.Set(p.nodeList())
 		n.Implicit = p.bool()
 
 	case OARRAYLIT, OMAPLIT:
 		n.Type = p.typ()
-		setNodeSeq(&n.List, p.nodeList())
+		n.List.Set(p.nodeList())
 		n.Implicit = p.bool()
 
 	case OKEY:
@@ -635,9 +635,9 @@
 		// }
 		x := Nod(OCALL, p.typ().Nod, nil)
 		if p.bool() {
-			setNodeSeq(&x.List, []*Node{p.node()})
+			x.List.Set([]*Node{p.node()})
 		} else {
-			setNodeSeq(&x.List, p.nodeList())
+			x.List.Set(p.nodeList())
 		}
 		return x
 
@@ -667,12 +667,12 @@
 	case OREAL, OIMAG, OAPPEND, OCAP, OCLOSE, ODELETE, OLEN, OMAKE, ONEW, OPANIC,
 		ORECOVER, OPRINT, OPRINTN:
 		n.Left, _ = p.nodesOrNil()
-		setNodeSeq(&n.List, p.nodeList())
+		n.List.Set(p.nodeList())
 		n.Isddd = p.bool()
 
 	case OCALL, OCALLFUNC, OCALLMETH, OCALLINTER, OGETG:
 		n.Left = p.node()
-		setNodeSeq(&n.List, p.nodeList())
+		n.List.Set(p.nodeList())
 		n.Isddd = p.bool()
 
 	case OCMPSTR, OCMPIFACE:
@@ -698,45 +698,45 @@
 		n.Etype = EType(p.int())
 
 	case OAS2, OASWB:
-		setNodeSeq(&n.List, p.nodeList())
-		setNodeSeq(&n.Rlist, p.nodeList())
+		n.List.Set(p.nodeList())
+		n.Rlist.Set(p.nodeList())
 
 	case OAS2DOTTYPE, OAS2FUNC, OAS2MAPR, OAS2RECV:
-		setNodeSeq(&n.List, p.nodeList())
-		setNodeSeq(&n.Rlist, p.nodeList())
+		n.List.Set(p.nodeList())
+		n.Rlist.Set(p.nodeList())
 
 	case ORETURN:
-		setNodeSeq(&n.List, p.nodeList())
+		n.List.Set(p.nodeList())
 
 	case OPROC, ODEFER:
 		n.Left = p.node()
 
 	case OIF:
-		setNodeSeq(&n.Ninit, p.nodeList())
+		n.Ninit.Set(p.nodeList())
 		n.Left = p.node()
 		n.Nbody.Set(p.nodeList())
-		setNodeSeq(&n.Rlist, p.nodeList())
+		n.Rlist.Set(p.nodeList())
 
 	case OFOR:
-		setNodeSeq(&n.Ninit, p.nodeList())
+		n.Ninit.Set(p.nodeList())
 		n.Left, n.Right = p.nodesOrNil()
 		n.Nbody.Set(p.nodeList())
 
 	case ORANGE:
 		if p.bool() {
-			setNodeSeq(&n.List, p.nodeList())
+			n.List.Set(p.nodeList())
 		}
 		n.Right = p.node()
 		n.Nbody.Set(p.nodeList())
 
 	case OSELECT, OSWITCH:
-		setNodeSeq(&n.Ninit, p.nodeList())
+		n.Ninit.Set(p.nodeList())
 		n.Left, _ = p.nodesOrNil()
-		setNodeSeq(&n.List, p.nodeList())
+		n.List.Set(p.nodeList())
 
 	case OCASE, OXCASE:
 		if p.bool() {
-			setNodeSeq(&n.List, p.nodeList())
+			n.List.Set(p.nodeList())
 		}
 		n.Nbody.Set(p.nodeList())
 
diff --git a/src/cmd/compile/internal/gc/cgen.go b/src/cmd/compile/internal/gc/cgen.go
index c9d4897..439c52d 100644
--- a/src/cmd/compile/internal/gc/cgen.go
+++ b/src/cmd/compile/internal/gc/cgen.go
@@ -1752,7 +1752,7 @@
 func bvgenjump(n, res *Node, wantTrue, geninit bool) {
 	init := n.Ninit
 	if !geninit {
-		setNodeSeq(&n.Ninit, nil)
+		n.Ninit.Set(nil)
 	}
 	p1 := Gbranch(obj.AJMP, nil, 0)
 	p2 := Pc
@@ -1762,7 +1762,7 @@
 	Bgen(n, wantTrue, 0, p2)
 	Thearch.Gmove(Nodbool(false), res)
 	Patch(p3, Pc)
-	setNodeSeq(&n.Ninit, init)
+	n.Ninit.Set(init.Slice())
 }
 
 // bgenx is the backend for Bgen and Bvgen.
@@ -1920,11 +1920,11 @@
 		if Isfloat[nr.Type.Etype] {
 			// Brcom is not valid on floats when NaN is involved.
 			ll := n.Ninit // avoid re-genning Ninit
-			setNodeSeq(&n.Ninit, nil)
+			n.Ninit.Set(nil)
 			if genval {
 				bgenx(n, res, true, likely, to)
 				Thearch.Gins(Thearch.Optoas(OXOR, Types[TUINT8]), Nodintconst(1), res) // res = !res
-				setNodeSeq(&n.Ninit, ll)
+				n.Ninit.Set(ll.Slice())
 				return
 			}
 			p1 := Gbranch(obj.AJMP, nil, 0)
@@ -1933,7 +1933,7 @@
 			bgenx(n, res, true, -likely, p2)
 			Patch(Gbranch(obj.AJMP, nil, 0), to)
 			Patch(p2, Pc)
-			setNodeSeq(&n.Ninit, ll)
+			n.Ninit.Set(ll.Slice())
 			return
 		}
 
@@ -2799,13 +2799,13 @@
 		Dump("cgen_append-n", n)
 		Dump("cgen_append-res", res)
 	}
-	if res.Op != ONAME && !samesafeexpr(res, nodeSeqFirst(n.List)) {
+	if res.Op != ONAME && !samesafeexpr(res, n.List.First()) {
 		Dump("cgen_append-n", n)
 		Dump("cgen_append-res", res)
 		Fatalf("append not lowered")
 	}
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		if it.N().Ullman >= UINF {
+	for _, n1 := range n.List.Slice() {
+		if n1.Ullman >= UINF {
 			Fatalf("append with function call arguments")
 		}
 	}
@@ -2814,7 +2814,7 @@
 	//
 	// If res and src are the same, we can avoid writing to base and cap
 	// unless we grow the underlying array.
-	needFullUpdate := !samesafeexpr(res, nodeSeqFirst(n.List))
+	needFullUpdate := !samesafeexpr(res, n.List.First())
 
 	// Copy src triple into base, len, cap.
 	base := temp(Types[Tptr])
@@ -2822,7 +2822,7 @@
 	cap := temp(Types[TUINT])
 
 	var src Node
-	Igen(nodeSeqFirst(n.List), &src, nil)
+	Igen(n.List.First(), &src, nil)
 	src.Type = Types[Tptr]
 	Thearch.Gmove(&src, base)
 	src.Type = Types[TUINT]
@@ -2835,7 +2835,7 @@
 	var rlen Node
 	Regalloc(&rlen, Types[TUINT], nil)
 	Thearch.Gmove(len, &rlen)
-	Thearch.Ginscon(Thearch.Optoas(OADD, Types[TUINT]), int64(nodeSeqLen(n.List)-1), &rlen)
+	Thearch.Ginscon(Thearch.Optoas(OADD, Types[TUINT]), int64(n.List.Len()-1), &rlen)
 	p := Thearch.Ginscmp(OLE, Types[TUINT], &rlen, cap, +1)
 	// Note: rlen and src are Regrealloc'ed below at the target of the
 	// branch we just emitted; do not reuse these Go variables for
@@ -2905,7 +2905,7 @@
 	dst.Xoffset += int64(Widthptr)
 	Regalloc(&r1, Types[TUINT], nil)
 	Thearch.Gmove(len, &r1)
-	Thearch.Ginscon(Thearch.Optoas(OADD, Types[TUINT]), int64(nodeSeqLen(n.List)-1), &r1)
+	Thearch.Ginscon(Thearch.Optoas(OADD, Types[TUINT]), int64(n.List.Len()-1), &r1)
 	Thearch.Gmove(&r1, &dst)
 	Regfree(&r1)
 	dst.Xoffset += int64(Widthptr)
diff --git a/src/cmd/compile/internal/gc/closure.go b/src/cmd/compile/internal/gc/closure.go
index d040bdc..af5c7c9 100644
--- a/src/cmd/compile/internal/gc/closure.go
+++ b/src/cmd/compile/internal/gc/closure.go
@@ -26,30 +26,29 @@
 	// references to these variables need to
 	// refer to the variables in the external
 	// function declared below; see walkclosure.
-	setNodeSeq(&n.List, ntype.List)
+	n.List.Set(ntype.List.Slice())
 
-	setNodeSeq(&n.Rlist, ntype.Rlist)
-	setNodeSeq(&ntype.List, nil)
-	setNodeSeq(&ntype.Rlist, nil)
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		name = it.N().Left
+	n.Rlist.Set(ntype.Rlist.Slice())
+	ntype.List.Set(nil)
+	ntype.Rlist.Set(nil)
+	for _, n1 := range n.List.Slice() {
+		name = n1.Left
 		if name != nil {
 			name = newname(name.Sym)
 		}
-		a = Nod(ODCLFIELD, name, it.N().Right)
-		a.Isddd = it.N().Isddd
+		a = Nod(ODCLFIELD, name, n1.Right)
+		a.Isddd = n1.Isddd
 		if name != nil {
 			name.Isddd = a.Isddd
 		}
-		appendNodeSeqNode(&ntype.List, a)
+		ntype.List.Append(a)
 	}
-
-	for it := nodeSeqIterate(n.Rlist); !it.Done(); it.Next() {
-		name = it.N().Left
+	for _, n2 := range n.Rlist.Slice() {
+		name = n2.Left
 		if name != nil {
 			name = newname(name.Sym)
 		}
-		appendNodeSeqNode(&ntype.Rlist, Nod(ODCLFIELD, name, it.N().Right))
+		ntype.Rlist.Append(Nod(ODCLFIELD, name, n2.Right))
 	}
 }
 
@@ -177,8 +176,8 @@
 	// that begins by reading closure parameters.
 	xtype := Nod(OTFUNC, nil, nil)
 
-	setNodeSeq(&xtype.List, func_.List)
-	setNodeSeq(&xtype.Rlist, func_.Rlist)
+	xtype.List.Set(func_.List.Slice())
+	xtype.Rlist.Set(func_.Rlist.Slice())
 
 	// create the function
 	xfunc := Nod(ODCLFUNC, nil, nil)
@@ -205,8 +204,8 @@
 	func_.Func.Closure = xfunc
 
 	func_.Nbody.Set(nil)
-	setNodeSeq(&func_.List, nil)
-	setNodeSeq(&func_.Rlist, nil)
+	func_.List.Set(nil)
+	func_.Rlist.Set(nil)
 
 	return xfunc
 }
@@ -426,7 +425,7 @@
 
 	typ := Nod(OTSTRUCT, nil, nil)
 
-	setNodeSeq(&typ.List, []*Node{Nod(ODCLFIELD, newname(Lookup(".F")), typenod(Types[TUINTPTR]))})
+	typ.List.Set([]*Node{Nod(ODCLFIELD, newname(Lookup(".F")), typenod(Types[TUINTPTR]))})
 	var typ1 *Node
 	for _, v := range func_.Func.Cvars.Slice() {
 		if v.Op == OXXX {
@@ -436,13 +435,13 @@
 		if !v.Name.Byval {
 			typ1 = Nod(OIND, typ1, nil)
 		}
-		appendNodeSeqNode(&typ.List, Nod(ODCLFIELD, newname(v.Sym), typ1))
+		typ.List.Append(Nod(ODCLFIELD, newname(v.Sym), typ1))
 	}
 
 	clos := Nod(OCOMPLIT, nil, Nod(OIND, typ, nil))
 	clos.Esc = func_.Esc
 	clos.Right.Implicit = true
-	setNodeSeq(&clos.List, append([]*Node{Nod(OCFUNC, func_.Func.Closure.Func.Nname, nil)}, func_.Func.Enter.Slice()...))
+	clos.List.Set(append([]*Node{Nod(OCFUNC, func_.Func.Closure.Func.Nname, nil)}, func_.Func.Enter.Slice()...))
 
 	// Force type conversion from *struct to the func type.
 	clos = Nod(OCONVNOP, clos, nil)
@@ -550,7 +549,7 @@
 		l = append(l, fld)
 	}
 
-	setNodeSeq(&xtype.List, l)
+	xtype.List.Set(l)
 	i = 0
 	l = nil
 	var retargs []*Node
@@ -563,7 +562,7 @@
 		l = append(l, Nod(ODCLFIELD, n, typenod(t.Type)))
 	}
 
-	setNodeSeq(&xtype.Rlist, l)
+	xtype.Rlist.Set(l)
 
 	xfunc.Func.Dupok = true
 	xfunc.Func.Nname = newfuncname(sym)
@@ -600,14 +599,14 @@
 	}
 
 	call := Nod(OCALL, Nod(OXDOT, ptr, meth), nil)
-	setNodeSeq(&call.List, callargs)
+	call.List.Set(callargs)
 	call.Isddd = ddd
 	if t0.Outtuple == 0 {
 		body = append(body, call)
 	} else {
 		n := Nod(OAS2, nil, nil)
-		setNodeSeq(&n.List, retargs)
-		setNodeSeq(&n.Rlist, []*Node{call})
+		n.List.Set(retargs)
+		n.Rlist.Set([]*Node{call})
 		body = append(body, n)
 		n = Nod(ORETURN, nil, nil)
 		body = append(body, n)
@@ -640,14 +639,14 @@
 	}
 
 	typ := Nod(OTSTRUCT, nil, nil)
-	setNodeSeq(&typ.List, []*Node{Nod(ODCLFIELD, newname(Lookup("F")), typenod(Types[TUINTPTR]))})
-	appendNodeSeqNode(&typ.List, Nod(ODCLFIELD, newname(Lookup("R")), typenod(n.Left.Type)))
+	typ.List.Set([]*Node{Nod(ODCLFIELD, newname(Lookup("F")), typenod(Types[TUINTPTR]))})
+	typ.List.Append(Nod(ODCLFIELD, newname(Lookup("R")), typenod(n.Left.Type)))
 
 	clos := Nod(OCOMPLIT, nil, Nod(OIND, typ, nil))
 	clos.Esc = n.Esc
 	clos.Right.Implicit = true
-	setNodeSeq(&clos.List, []*Node{Nod(OCFUNC, n.Func.Nname, nil)})
-	appendNodeSeqNode(&clos.List, n.Left)
+	clos.List.Set([]*Node{Nod(OCFUNC, n.Func.Nname, nil)})
+	clos.List.Append(n.Left)
 
 	// Force type conversion from *struct to the func type.
 	clos = Nod(OCONVNOP, clos, nil)
diff --git a/src/cmd/compile/internal/gc/const.go b/src/cmd/compile/internal/gc/const.go
index 0a9b3c0..f2a3e7d 100644
--- a/src/cmd/compile/internal/gc/const.go
+++ b/src/cmd/compile/internal/gc/const.go
@@ -543,7 +543,7 @@
 
 		// merge adjacent constants in the argument list.
 	case OADDSTR:
-		s := nodeSeqSlice(n.List)
+		s := n.List.Slice()
 		for i1 := 0; i1 < len(s); i1++ {
 			if Isconst(s[i1], CTSTR) && i1+1 < len(s) && Isconst(s[i1+1], CTSTR) {
 				// merge from i1 up to but not including i2
@@ -567,7 +567,7 @@
 			n.Op = OLITERAL
 			n.SetVal(s[0].Val())
 		} else {
-			setNodeSeq(&n.List, s)
+			n.List.Set(s)
 		}
 
 		return
@@ -1736,14 +1736,13 @@
 	if hascallchan(n.Left) || hascallchan(n.Right) {
 		return true
 	}
-
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		if hascallchan(it.N()) {
+	for _, n1 := range n.List.Slice() {
+		if hascallchan(n1) {
 			return true
 		}
 	}
-	for it := nodeSeqIterate(n.Rlist); !it.Done(); it.Next() {
-		if hascallchan(it.N()) {
+	for _, n2 := range n.Rlist.Slice() {
+		if hascallchan(n2) {
 			return true
 		}
 	}
diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index 22ab3cc..6cda036 100644
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -228,7 +228,7 @@
 		e := el.N
 		as2 := Nod(OAS2, nil, nil)
 		setNodeSeq(&as2.List, vl)
-		setNodeSeqNode(&as2.Rlist, e)
+		as2.Rlist.Set([]*Node{e})
 		var v *Node
 		for ; vl != nil; vl = vl.Next {
 			v = vl.N
@@ -438,17 +438,17 @@
 }
 
 func colasdefn(left Nodes, defn *Node) {
-	for it := nodeSeqIterate(left); !it.Done(); it.Next() {
-		if it.N().Sym != nil {
-			it.N().Sym.Flags |= SymUniq
+	for _, n1 := range left.Slice() {
+		if n1.Sym != nil {
+			n1.Sym.Flags |= SymUniq
 		}
 	}
 
 	nnew := 0
 	nerr := 0
 	var n *Node
-	for it := nodeSeqIterate(left); !it.Done(); it.Next() {
-		n = it.N()
+	for i2, n2 := range left.Slice() {
+		n = n2
 		if isblank(n) {
 			continue
 		}
@@ -474,8 +474,8 @@
 		n = newname(n.Sym)
 		declare(n, dclcontext)
 		n.Name.Defn = defn
-		appendNodeSeqNode(&defn.Ninit, Nod(ODCL, n, nil))
-		*it.P() = n
+		defn.Ninit.Append(Nod(ODCL, n, nil))
+		left.Slice()[i2] = n
 	}
 
 	if nnew == 0 && nerr == 0 {
@@ -492,11 +492,11 @@
 	colasdefn(as.List, as)
 
 	// make the tree prettier; not necessary
-	if nodeSeqLen(as.List) == 1 && nodeSeqLen(as.Rlist) == 1 {
-		as.Left = nodeSeqFirst(as.List)
-		as.Right = nodeSeqFirst(as.Rlist)
-		setNodeSeq(&as.List, nil)
-		setNodeSeq(&as.Rlist, nil)
+	if as.List.Len() == 1 && as.Rlist.Len() == 1 {
+		as.Left = as.List.First()
+		as.Right = as.Rlist.First()
+		as.List.Set(nil)
+		as.Rlist.Set(nil)
 		as.Op = OAS
 	}
 
@@ -570,7 +570,7 @@
 	// re-start the variable generation number
 	// we want to use small numbers for the return variables,
 	// so let them have the chunk starting at 1.
-	vargen = nodeSeqLen(nt.Rlist)
+	vargen = nt.Rlist.Len()
 
 	// declare the receiver and in arguments.
 	// no n->defn because type checking of func header
@@ -592,8 +592,7 @@
 	}
 
 	var n *Node
-	for it := nodeSeqIterate(nt.List); !it.Done(); it.Next() {
-		n = it.N()
+	for _, n = range nt.List.Slice() {
 		if n.Op != ODCLFIELD {
 			Fatalf("funcargs in %v", Oconv(n.Op, 0))
 		}
@@ -609,12 +608,10 @@
 	}
 
 	// declare the out arguments.
-	gen := nodeSeqLen(nt.List)
+	gen := nt.List.Len()
 	var i int = 0
 	var nn *Node
-	for it := nodeSeqIterate(nt.Rlist); !it.Done(); it.Next() {
-		n = it.N()
-
+	for _, n = range nt.Rlist.Slice() {
 		if n.Op != ODCLFIELD {
 			Fatalf("funcargs out %v", Oconv(n.Op, 0))
 		}
@@ -964,10 +961,10 @@
 	}
 
 	tp := &t.Type
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		f := interfacefield(it.N())
+	for _, n := range l {
+		f := interfacefield(n)
 
-		if it.N().Left == nil && f.Type.Etype == TINTER {
+		if n.Left == nil && f.Type.Etype == TINTER {
 			// embedded interface, inline methods
 			for t1 := f.Type.Type; t1 != nil; t1 = t1.Down {
 				f = typ(TFIELD)
@@ -1536,8 +1533,8 @@
 }
 
 func (c *nowritebarrierrecChecker) visitcodelist(l Nodes) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		c.visitcode(it.N())
+	for _, n := range l.Slice() {
+		c.visitcode(n)
 	}
 }
 
diff --git a/src/cmd/compile/internal/gc/esc.go b/src/cmd/compile/internal/gc/esc.go
index 5dc4348..a814ce1 100644
--- a/src/cmd/compile/internal/gc/esc.go
+++ b/src/cmd/compile/internal/gc/esc.go
@@ -111,8 +111,8 @@
 }
 
 func (v *bottomUpVisitor) visitcodelist(l Nodes, min uint32) uint32 {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		min = v.visitcode(it.N(), min)
+	for _, n := range l.Slice() {
+		min = v.visitcode(n, min)
 	}
 	return min
 }
@@ -523,8 +523,8 @@
 var nonlooping Label
 
 func escloopdepthlist(e *EscState, l Nodes) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		escloopdepth(e, it.N())
+	for _, n := range l.Slice() {
+		escloopdepth(e, n)
 	}
 }
 
@@ -567,8 +567,8 @@
 }
 
 func esclist(e *EscState, l Nodes, up *Node) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		esc(e, it.N(), up)
+	for _, n := range l.Slice() {
+		esc(e, n, up)
 	}
 }
 
@@ -597,10 +597,10 @@
 	// must happen before processing of switch body,
 	// so before recursion.
 	if n.Op == OSWITCH && n.Left != nil && n.Left.Op == OTYPESW {
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() { // cases
+		for _, n1 := range n.List.Slice() { // cases
 			// it.N().Rlist is the variable per case
-			if nodeSeqLen(it.N().Rlist) != 0 {
-				e.nodeEscState(nodeSeqFirst(it.N().Rlist)).Escloopdepth = e.loopdepth
+			if n1.Rlist.Len() != 0 {
+				e.nodeEscState(n1.Rlist.First()).Escloopdepth = e.loopdepth
 			}
 		}
 	}
@@ -659,7 +659,7 @@
 		n.Left.Sym.Label = nil
 
 	case ORANGE:
-		if nodeSeqLen(n.List) >= 2 {
+		if n.List.Len() >= 2 {
 			// Everything but fixed array is a dereference.
 
 			// If fixed array is really the address of fixed array,
@@ -667,20 +667,20 @@
 			// dereferenced (see #12588)
 			if Isfixedarray(n.Type) &&
 				!(Isptr[n.Right.Type.Etype] && Eqtype(n.Right.Type.Type, n.Type)) {
-				escassign(e, nodeSeqSecond(n.List), n.Right)
+				escassign(e, n.List.Second(), n.Right)
 			} else {
-				escassignDereference(e, nodeSeqSecond(n.List), n.Right)
+				escassignDereference(e, n.List.Second(), n.Right)
 			}
 		}
 
 	case OSWITCH:
 		if n.Left != nil && n.Left.Op == OTYPESW {
-			for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
+			for _, n2 := range n.List.Slice() {
 				// cases
 				// n.Left.Right is the argument of the .(type),
 				// it.N().Rlist is the variable per case
-				if nodeSeqLen(it.N().Rlist) != 0 {
-					escassign(e, nodeSeqFirst(it.N().Rlist), n.Left.Right)
+				if n2.Rlist.Len() != 0 {
+					escassign(e, n2.Rlist.First(), n.Left.Right)
 				}
 			}
 		}
@@ -721,10 +721,10 @@
 		escassign(e, n.Left, n.Right)
 
 	case OAS2: // x,y = a,b
-		if nodeSeqLen(n.List) == nodeSeqLen(n.Rlist) {
+		if n.List.Len() == n.Rlist.Len() {
 			lrit := nodeSeqIterate(n.Rlist)
-			for llit := nodeSeqIterate(n.List); !llit.Done(); llit.Next() {
-				escassign(e, llit.N(), lrit.N())
+			for _, n3 := range n.List.Slice() {
+				escassign(e, n3, lrit.N())
 				lrit.Next()
 			}
 		}
@@ -732,7 +732,7 @@
 	case OAS2RECV, // v, ok = <-ch
 		OAS2MAPR,    // v, ok = m[k]
 		OAS2DOTTYPE: // v, ok = x.(type)
-		escassign(e, nodeSeqFirst(n.List), nodeSeqFirst(n.Rlist))
+		escassign(e, n.List.First(), n.Rlist.First())
 
 	case OSEND: // ch <- x
 		escassign(e, &e.theSink, n.Right)
@@ -750,8 +750,8 @@
 		escassign(e, &e.theSink, n.Left.Left)
 
 		escassign(e, &e.theSink, n.Left.Right) // ODDDARG for call
-		for it := nodeSeqIterate(n.Left.List); !it.Done(); it.Next() {
-			escassign(e, &e.theSink, it.N())
+		for _, n4 := range n.Left.List.Slice() {
+			escassign(e, &e.theSink, n4)
 		}
 
 	case OCALLMETH, OCALLFUNC, OCALLINTER:
@@ -759,7 +759,7 @@
 
 		// esccall already done on n->rlist->n. tie it's escretval to n->list
 	case OAS2FUNC: // x,y = f()
-		lrit := nodeSeqIterate(e.nodeEscState(nodeSeqFirst(n.Rlist)).Escretval)
+		lrit := nodeSeqIterate(e.nodeEscState(n.Rlist.First()).Escretval)
 
 		var llit nodeSeqIterator
 		for llit = nodeSeqIterate(n.List); !lrit.Done() && !llit.Done(); llit.Next() {
@@ -772,11 +772,11 @@
 
 	case ORETURN:
 		ll := n.List
-		if nodeSeqLen(n.List) == 1 && Curfn.Type.Outtuple > 1 {
+		if n.List.Len() == 1 && Curfn.Type.Outtuple > 1 {
 			// OAS2FUNC in disguise
 			// esccall already done on n->list->n
 			// tie n->list->n->escretval to curfn->dcl PPARAMOUT's
-			ll = e.nodeEscState(nodeSeqFirst(n.List)).Escretval
+			ll = e.nodeEscState(n.List.First()).Escretval
 		}
 
 		llit := nodeSeqIterate(ll)
@@ -808,13 +808,13 @@
 			}
 		} else {
 			// append(slice1, slice2...) -- slice2 itself does not escape, but contents do.
-			slice2 := nodeSeqSecond(n.List)
+			slice2 := n.List.Second()
 			escassignDereference(e, &e.theSink, slice2) // lose track of assign of dereference
 			if Debug['m'] > 2 {
 				Warnl(n.Lineno, "%v special treatment of append(slice1, slice2...) %v", e.curfnSym(n), Nconv(n, obj.FmtShort))
 			}
 		}
-		escassignDereference(e, &e.theSink, nodeSeqFirst(n.List)) // The original elements are now leaked, too
+		escassignDereference(e, &e.theSink, n.List.First()) // The original elements are now leaked, too
 
 	case OCOPY:
 		escassignDereference(e, &e.theSink, n.Right) // lose track of assign of dereference
@@ -831,16 +831,15 @@
 			// Slice itself is not leaked until proven otherwise
 			e.track(n)
 		}
-
 		// Link values to array/slice
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			escassign(e, n, it.N().Right)
+		for _, n5 := range n.List.Slice() {
+			escassign(e, n, n5.Right)
 		}
 
 		// Link values to struct.
 	case OSTRUCTLIT:
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			escassign(e, n, it.N().Right)
+		for _, n6 := range n.List.Slice() {
+			escassign(e, n, n6.Right)
 		}
 
 	case OPTRLIT:
@@ -857,11 +856,10 @@
 
 	case OMAPLIT:
 		e.track(n)
-
 		// Keys and values make it to memory, lose track.
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			escassign(e, &e.theSink, it.N().Left)
-			escassign(e, &e.theSink, it.N().Right)
+		for _, n7 := range n.List.Slice() {
+			escassign(e, &e.theSink, n7.Left)
+			escassign(e, &e.theSink, n7.Right)
 		}
 
 		// Link addresses of captured variables to closure.
@@ -1036,8 +1034,8 @@
 	// Flowing multiple returns to a single dst happens when
 	// analyzing "go f(g())": here g() flows to sink (issue 4529).
 	case OCALLMETH, OCALLFUNC, OCALLINTER:
-		for it := nodeSeqIterate(e.nodeEscState(src).Escretval); !it.Done(); it.Next() {
-			escflows(e, dst, it.N())
+		for _, n := range e.nodeEscState(src).Escretval.Slice() {
+			escflows(e, dst, n)
 		}
 
 		// A non-pointer escaping from a struct does not concern us.
@@ -1071,7 +1069,7 @@
 	case OAPPEND:
 		// Append returns first argument.
 		// Subsequent arguments are already leaked because they are operands to append.
-		escassign(e, dst, nodeSeqFirst(src.List))
+		escassign(e, dst, src.List.First())
 
 	case OINDEX:
 		// Index of array preserves input value.
@@ -1369,8 +1367,8 @@
 	}
 
 	ll := n.List
-	if nodeSeqLen(n.List) == 1 {
-		a := nodeSeqFirst(n.List)
+	if n.List.Len() == 1 {
+		a := n.List.First()
 		if a.Type.Etype == TSTRUCT && a.Type.Funarg { // f(g()).
 			ll = e.nodeEscState(a).Escretval
 		}
@@ -1379,10 +1377,10 @@
 	if indirect {
 		// We know nothing!
 		// Leak all the parameters
-		for it := nodeSeqIterate(ll); !it.Done(); it.Next() {
-			escassign(e, &e.theSink, it.N())
+		for _, n1 := range ll.Slice() {
+			escassign(e, &e.theSink, n1)
 			if Debug['m'] > 2 {
-				fmt.Printf("%v::esccall:: indirect call <- %v, untracked\n", linestr(lineno), Nconv(it.N(), obj.FmtShort))
+				fmt.Printf("%v::esccall:: indirect call <- %v, untracked\n", linestr(lineno), Nconv(n1, obj.FmtShort))
 			}
 		}
 		// Set up bogus outputs
@@ -1407,13 +1405,12 @@
 
 		// function in same mutually recursive group. Incorporate into flow graph.
 		//		print("esc local fn: %N\n", fn->ntype);
-		if fn.Name.Defn.Esc == EscFuncUnknown || nodeSeqLen(nE.Escretval) != 0 {
+		if fn.Name.Defn.Esc == EscFuncUnknown || nE.Escretval.Len() != 0 {
 			Fatalf("graph inconsistency")
 		}
-
 		// set up out list on this call node
-		for it := nodeSeqIterate(fn.Name.Param.Ntype.Rlist); !it.Done(); it.Next() {
-			appendNodeSeqNode(&nE.Escretval, it.N().Left) // type.rlist ->  dclfield -> ONAME (PPARAMOUT)
+		for _, n2 := range fn.Name.Param.Ntype.Rlist.Slice() {
+			nE.Escretval.Append(n2.Left) // type.rlist ->  dclfield -> ONAME (PPARAMOUT)
 		}
 
 		// Receiver.
@@ -1458,7 +1455,7 @@
 	}
 
 	// Imported or completely analyzed function. Use the escape tags.
-	if nodeSeqLen(nE.Escretval) != 0 {
+	if nE.Escretval.Len() != 0 {
 		Fatalf("esc already decorated call %v\n", Nconv(n, obj.FmtSign))
 	}
 
@@ -1739,7 +1736,7 @@
 		}
 
 	case OAPPEND:
-		escwalk(e, level, dst, nodeSeqFirst(src.List))
+		escwalk(e, level, dst, src.List.First())
 
 	case ODDDARG:
 		if leaks {
@@ -1756,8 +1753,8 @@
 		if Isfixedarray(src.Type) {
 			break
 		}
-		for it := nodeSeqIterate(src.List); !it.Done(); it.Next() {
-			escwalk(e, level.dec(), dst, it.N().Right)
+		for _, n1 := range src.List.Slice() {
+			escwalk(e, level.dec(), dst, n1.Right)
 		}
 
 		fallthrough
@@ -1809,13 +1806,13 @@
 	// See e.g. #10466
 	// This can only happen with functions returning a single result.
 	case OCALLMETH, OCALLFUNC, OCALLINTER:
-		if nodeSeqLen(srcE.Escretval) != 0 {
+		if srcE.Escretval.Len() != 0 {
 			if Debug['m'] > 1 {
 				fmt.Printf("%v:[%d] dst %v escwalk replace src: %v with %v\n",
 					linestr(lineno), e.loopdepth,
-					Nconv(dst, obj.FmtShort), Nconv(src, obj.FmtShort), Nconv(nodeSeqFirst(srcE.Escretval), obj.FmtShort))
+					Nconv(dst, obj.FmtShort), Nconv(src, obj.FmtShort), Nconv(srcE.Escretval.First(), obj.FmtShort))
 			}
-			src = nodeSeqFirst(srcE.Escretval)
+			src = srcE.Escretval.First()
 			srcE = e.nodeEscState(src)
 		}
 	}
diff --git a/src/cmd/compile/internal/gc/export.go b/src/cmd/compile/internal/gc/export.go
index 5c53da3..e46dcd1 100644
--- a/src/cmd/compile/internal/gc/export.go
+++ b/src/cmd/compile/internal/gc/export.go
@@ -107,8 +107,8 @@
 
 // Look for anything we need for the inline body
 func reexportdeplist(ll Nodes) {
-	for it := nodeSeqIterate(ll); !it.Done(); it.Next() {
-		reexportdep(it.N())
+	for _, n := range ll.Slice() {
+		reexportdep(n)
 	}
 }
 
diff --git a/src/cmd/compile/internal/gc/fmt.go b/src/cmd/compile/internal/gc/fmt.go
index ac1d8cb..a900376 100644
--- a/src/cmd/compile/internal/gc/fmt.go
+++ b/src/cmd/compile/internal/gc/fmt.go
@@ -800,10 +800,10 @@
 	// block starting with the init statements.
 
 	// if we can just say "for" n->ninit; ... then do so
-	simpleinit := nodeSeqLen(n.Ninit) == 1 && nodeSeqLen(nodeSeqFirst(n.Ninit).Ninit) == 0 && stmtwithinit(n.Op)
+	simpleinit := n.Ninit.Len() == 1 && n.Ninit.First().Ninit.Len() == 0 && stmtwithinit(n.Op)
 
 	// otherwise, print the inits as separate statements
-	complexinit := nodeSeqLen(n.Ninit) != 0 && !simpleinit && (fmtmode != FErr)
+	complexinit := n.Ninit.Len() != 0 && !simpleinit && (fmtmode != FErr)
 
 	// but if it was for if/for/switch, put in an extra surrounding block to limit the scope
 	extrablock := complexinit && stmtwithinit(n.Op)
@@ -885,11 +885,11 @@
 
 	case OIF:
 		if simpleinit {
-			f += fmt.Sprintf("if %v; %v { %v }", nodeSeqFirst(n.Ninit), n.Left, n.Nbody)
+			f += fmt.Sprintf("if %v; %v { %v }", n.Ninit.First(), n.Left, n.Nbody)
 		} else {
 			f += fmt.Sprintf("if %v { %v }", n.Left, n.Nbody)
 		}
-		if nodeSeqLen(n.Rlist) != 0 {
+		if n.Rlist.Len() != 0 {
 			f += fmt.Sprintf(" else { %v }", n.Rlist)
 		}
 
@@ -901,7 +901,7 @@
 
 		f += "for"
 		if simpleinit {
-			f += fmt.Sprintf(" %v;", nodeSeqFirst(n.Ninit))
+			f += fmt.Sprintf(" %v;", n.Ninit.First())
 		} else if n.Right != nil {
 			f += " ;"
 		}
@@ -924,7 +924,7 @@
 			break
 		}
 
-		if nodeSeqLen(n.List) == 0 {
+		if n.List.Len() == 0 {
 			f += fmt.Sprintf("for range %v { %v }", n.Right, n.Nbody)
 			break
 		}
@@ -939,7 +939,7 @@
 
 		f += Oconv(n.Op, obj.FmtSharp)
 		if simpleinit {
-			f += fmt.Sprintf(" %v;", nodeSeqFirst(n.Ninit))
+			f += fmt.Sprintf(" %v;", n.Ninit.First())
 		}
 		if n.Left != nil {
 			f += Nconv(n.Left, 0)
@@ -948,7 +948,7 @@
 		f += fmt.Sprintf(" { %v }", n.List)
 
 	case OCASE, OXCASE:
-		if nodeSeqLen(n.List) != 0 {
+		if n.List.Len() != 0 {
 			f += fmt.Sprintf("case %v: %v", Hconv(n.List, obj.FmtComma), n.Nbody)
 		} else {
 			f += fmt.Sprintf("default: %v", n.Nbody)
@@ -1391,7 +1391,7 @@
 		return f
 
 	case OMAKEMAP, OMAKECHAN, OMAKESLICE:
-		if nodeSeqLen(n.List) != 0 { // pre-typecheck
+		if n.List.Len() != 0 { // pre-typecheck
 			return fmt.Sprintf("make(%v, %v)", n.Type, Hconv(n.List, obj.FmtComma))
 		}
 		if n.Right != nil {
@@ -1450,11 +1450,11 @@
 	case OADDSTR:
 		var f string
 		i := 0
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
+		for _, n1 := range n.List.Slice() {
 			if i != 0 {
 				f += " + "
 			}
-			f += exprfmt(it.N(), nprec)
+			f += exprfmt(n1, nprec)
 			i++
 		}
 
@@ -1523,7 +1523,7 @@
 			return buf.String()
 		}
 
-		if nodeSeqLen(n.Ninit) != 0 {
+		if n.Ninit.Len() != 0 {
 			fmt.Fprintf(&buf, "%v-init%v", Oconv(n.Op, 0), n.Ninit)
 			indent(&buf)
 		}
@@ -1576,12 +1576,12 @@
 		if n.Right != nil {
 			buf.WriteString(Nconv(n.Right, 0))
 		}
-		if nodeSeqLen(n.List) != 0 {
+		if n.List.Len() != 0 {
 			indent(&buf)
 			fmt.Fprintf(&buf, "%v-list%v", Oconv(n.Op, 0), n.List)
 		}
 
-		if nodeSeqLen(n.Rlist) != 0 {
+		if n.Rlist.Len() != 0 {
 			indent(&buf)
 			fmt.Fprintf(&buf, "%v-rlist%v", Oconv(n.Op, 0), n.Rlist)
 		}
@@ -1711,7 +1711,7 @@
 // Fmt '%H': NodeList.
 // Flags: all those of %N plus ',': separate with comma's instead of semicolons.
 func Hconv(l Nodes, flag int) string {
-	if nodeSeqLen(l) == 0 && fmtmode == FDbg {
+	if l.Len() == 0 && fmtmode == FDbg {
 		return "<nil>"
 	}
 
diff --git a/src/cmd/compile/internal/gc/gen.go b/src/cmd/compile/internal/gc/gen.go
index c30d0e0..12c296c 100644
--- a/src/cmd/compile/internal/gc/gen.go
+++ b/src/cmd/compile/internal/gc/gen.go
@@ -216,8 +216,8 @@
 
 // compile statements
 func Genlist(l Nodes) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		gen(it.N())
+	for _, n := range l.Slice() {
+		gen(n)
 	}
 }
 
@@ -440,7 +440,7 @@
 		r1.Type = byteptr
 		r2.Type = byteptr
 		setNodeSeq(&call.List, list(list(list1(&r1), &r2), typename(n.Left.Type)))
-		setNodeSeq(&call.List, ascompatte(OCALLFUNC, call, false, fn.Type.ParamsP(), call.List.Slice(), 0, nil))
+		call.List.Set(ascompatte(OCALLFUNC, call, false, fn.Type.ParamsP(), call.List.Slice(), 0, nil))
 		gen(call)
 		Regfree(&r1)
 		Regfree(&r2)
@@ -526,7 +526,7 @@
 	dowidth(fn.Type)
 	call := Nod(OCALLFUNC, fn, nil)
 	setNodeSeq(&call.List, list(list(list1(&r1), &r2), typename(n.Left.Type)))
-	setNodeSeq(&call.List, ascompatte(OCALLFUNC, call, false, fn.Type.ParamsP(), call.List.Slice(), 0, nil))
+	call.List.Set(ascompatte(OCALLFUNC, call, false, fn.Type.ParamsP(), call.List.Slice(), 0, nil))
 	gen(call)
 	Regfree(&r1)
 	Regfree(&r2)
@@ -638,7 +638,7 @@
 		goto ret
 	}
 
-	if nodeSeqLen(n.Ninit) > 0 {
+	if n.Ninit.Len() > 0 {
 		Genlist(n.Ninit)
 	}
 
@@ -845,7 +845,7 @@
 		Cgen_as_wb(n.Left, n.Right, true)
 
 	case OAS2DOTTYPE:
-		cgen_dottype(nodeSeqFirst(n.Rlist), nodeSeqFirst(n.List), nodeSeqSecond(n.List), needwritebarrier(nodeSeqFirst(n.List), nodeSeqFirst(n.Rlist)))
+		cgen_dottype(n.Rlist.First(), n.List.First(), n.List.Second(), needwritebarrier(n.List.First(), n.Rlist.First()))
 
 	case OCALLMETH:
 		cgen_callmeth(n, 0)
diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go
index c2faff7..69615ba 100644
--- a/src/cmd/compile/internal/gc/inl.go
+++ b/src/cmd/compile/internal/gc/inl.go
@@ -171,8 +171,8 @@
 
 // Look for anything we want to punt on.
 func ishairylist(ll Nodes, budget *int) bool {
-	for it := nodeSeqIterate(ll); !it.Done(); it.Next() {
-		if ishairy(it.N(), budget) {
+	for _, n := range ll.Slice() {
+		if ishairy(n, budget) {
 			return true
 		}
 	}
@@ -247,8 +247,8 @@
 // the exportlist.
 func inlcopylist(ll []*Node) []*Node {
 	s := make([]*Node, 0, nodeSeqLen(ll))
-	for it := nodeSeqIterate(ll); !it.Done(); it.Next() {
-		s = append(s, inlcopy(it.N()))
+	for _, n := range ll {
+		s = append(s, inlcopy(n))
 	}
 	return s
 }
@@ -270,9 +270,9 @@
 	}
 	m.Left = inlcopy(n.Left)
 	m.Right = inlcopy(n.Right)
-	setNodeSeq(&m.List, inlcopylist(n.List.Slice()))
-	setNodeSeq(&m.Rlist, inlcopylist(n.Rlist.Slice()))
-	setNodeSeq(&m.Ninit, inlcopylist(n.Ninit.Slice()))
+	m.List.Set(inlcopylist(n.List.Slice()))
+	m.Rlist.Set(inlcopylist(n.Rlist.Slice()))
+	m.Ninit.Set(inlcopylist(n.Ninit.Slice()))
 	m.Nbody.Set(inlcopylist(n.Nbody.Slice()))
 
 	return m
@@ -295,17 +295,17 @@
 	n.Op = OBLOCK
 
 	// n->ninit stays
-	setNodeSeq(&n.List, n.Nbody)
+	n.List.Set(n.Nbody.Slice())
 
 	n.Nbody.Set(nil)
-	setNodeSeq(&n.Rlist, nil)
+	n.Rlist.Set(nil)
 }
 
 // Turn an OINLCALL into a single valued expression.
 func inlconv2expr(np **Node) {
 	n := *np
-	r := nodeSeqFirst(n.Rlist)
-	addinit(&r, append(nodeSeqSlice(n.Ninit), n.Nbody.Slice()...))
+	r := n.Rlist.First()
+	addinit(&r, append(n.Ninit.Slice(), n.Nbody.Slice()...))
 	*np = r
 }
 
@@ -315,18 +315,18 @@
 // order will be preserved Used in return, oas2func and call
 // statements.
 func inlconv2list(n *Node) []*Node {
-	if n.Op != OINLCALL || nodeSeqLen(n.Rlist) == 0 {
+	if n.Op != OINLCALL || n.Rlist.Len() == 0 {
 		Fatalf("inlconv2list %v\n", Nconv(n, obj.FmtSign))
 	}
 
-	s := nodeSeqSlice(n.Rlist)
-	addinit(&s[0], append(nodeSeqSlice(n.Ninit), n.Nbody.Slice()...))
+	s := n.Rlist.Slice()
+	addinit(&s[0], append(n.Ninit.Slice(), n.Nbody.Slice()...))
 	return s
 }
 
 func inlnodelist(l Nodes) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		inlnode(it.P())
+	for i := range l.Slice() {
+		inlnode(&l.Slice()[i])
 	}
 }
 
@@ -367,9 +367,9 @@
 	lno := setlineno(n)
 
 	inlnodelist(n.Ninit)
-	for it := nodeSeqIterate(n.Ninit); !it.Done(); it.Next() {
-		if it.N().Op == OINLCALL {
-			inlconv2stmt(it.N())
+	for _, n1 := range n.Ninit.Slice() {
+		if n1.Op == OINLCALL {
+			inlconv2stmt(n1)
 		}
 	}
 
@@ -390,9 +390,9 @@
 	inlnodelist(n.List)
 	switch n.Op {
 	case OBLOCK:
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if it.N().Op == OINLCALL {
-				inlconv2stmt(it.N())
+		for _, n2 := range n.List.Slice() {
+			if n2.Op == OINLCALL {
+				inlconv2stmt(n2)
 			}
 		}
 
@@ -404,16 +404,16 @@
 		OCALLINTER,
 		OAPPEND,
 		OCOMPLEX:
-		if nodeSeqLen(n.List) == 1 && nodeSeqFirst(n.List).Op == OINLCALL && nodeSeqLen(nodeSeqFirst(n.List).Rlist) > 1 {
-			setNodeSeq(&n.List, inlconv2list(nodeSeqFirst(n.List)))
+		if n.List.Len() == 1 && n.List.First().Op == OINLCALL && n.List.First().Rlist.Len() > 1 {
+			n.List.Set(inlconv2list(n.List.First()))
 			break
 		}
 		fallthrough
 
 	default:
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if it.N().Op == OINLCALL {
-				inlconv2expr(it.P())
+		for i3, n3 := range n.List.Slice() {
+			if n3.Op == OINLCALL {
+				inlconv2expr(&n.List.Slice()[i3])
 			}
 		}
 	}
@@ -421,8 +421,8 @@
 	inlnodelist(n.Rlist)
 	switch n.Op {
 	case OAS2FUNC:
-		if nodeSeqFirst(n.Rlist).Op == OINLCALL {
-			setNodeSeq(&n.Rlist, inlconv2list(nodeSeqFirst(n.Rlist)))
+		if n.Rlist.First().Op == OINLCALL {
+			n.Rlist.Set(inlconv2list(n.Rlist.First()))
 			n.Op = OAS2
 			n.Typecheck = 0
 			typecheck(np, Etop)
@@ -431,12 +431,12 @@
 		fallthrough
 
 	default:
-		for it := nodeSeqIterate(n.Rlist); !it.Done(); it.Next() {
-			if it.N().Op == OINLCALL {
+		for i4, n4 := range n.Rlist.Slice() {
+			if n4.Op == OINLCALL {
 				if n.Op == OIF {
-					inlconv2stmt(it.N())
+					inlconv2stmt(n4)
 				} else {
-					inlconv2expr(it.P())
+					inlconv2expr(&n.Rlist.Slice()[i4])
 				}
 			}
 		}
@@ -585,7 +585,7 @@
 			typecheck(&ln.Name.Inlvar, Erv)
 
 			if ln.Class&^PHEAP != PAUTO {
-				appendNodeSeqNode(&ninit, Nod(ODCL, ln.Name.Inlvar, nil)) // otherwise gen won't emit the allocations for heapallocs
+				ninit.Append(Nod(ODCL, ln.Name.Inlvar, nil)) // otherwise gen won't emit the allocations for heapallocs
 			}
 		}
 	}
@@ -603,7 +603,7 @@
 			i++
 		}
 
-		appendNodeSeqNode(&ninit, Nod(ODCL, m, nil))
+		ninit.Append(Nod(ODCL, m, nil))
 		inlretvars = list(inlretvars, m)
 	}
 
@@ -625,7 +625,7 @@
 		as = Nod(OAS, tinlvar(t), n.Left.Left)
 		if as != nil {
 			typecheck(&as, Etop)
-			appendNodeSeqNode(&ninit, as)
+			ninit.Append(as)
 		}
 	}
 
@@ -649,17 +649,17 @@
 	// check if argument is actually a returned tuple from call.
 	multiret := 0
 
-	if nodeSeqLen(n.List) == 1 {
-		switch nodeSeqFirst(n.List).Op {
+	if n.List.Len() == 1 {
+		switch n.List.First().Op {
 		case OCALL, OCALLFUNC, OCALLINTER, OCALLMETH:
-			if nodeSeqFirst(n.List).Left.Type.Outtuple > 1 {
-				multiret = nodeSeqFirst(n.List).Left.Type.Outtuple - 1
+			if n.List.First().Left.Type.Outtuple > 1 {
+				multiret = n.List.First().Left.Type.Outtuple - 1
 			}
 		}
 	}
 
 	if variadic {
-		varargcount = nodeSeqLen(n.List) + multiret
+		varargcount = n.List.Len() + multiret
 		if n.Left.Op != ODOTMETH {
 			varargcount -= fn.Type.Thistuple
 		}
@@ -669,13 +669,13 @@
 	// assign arguments to the parameters' temp names
 	as = Nod(OAS2, nil, nil)
 
-	setNodeSeq(&as.Rlist, n.List)
+	as.Rlist.Set(n.List.Slice())
 	it := nodeSeqIterate(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 {
 		// non-method call to method
-		if nodeSeqLen(n.List) == 0 {
+		if n.List.Len() == 0 {
 			Fatalf("non-method call to method without first arg: %v", Nconv(n, obj.FmtSign))
 		}
 
@@ -688,12 +688,12 @@
 		if t == nil {
 			Fatalf("method call unknown receiver type: %v", Nconv(n, obj.FmtSign))
 		}
-		appendNodeSeqNode(&as.List, tinlvar(t))
+		as.List.Append(tinlvar(t))
 		it.Next() // track argument count.
 	}
 
 	// append ordinary arguments to LHS.
-	chkargcount := nodeSeqLen(n.List) > 1
+	chkargcount := n.List.Len() > 1
 
 	var vararg *Node    // the slice argument to a variadic call
 	var varargs []*Node // the list of LHS names to put in vararg.
@@ -706,13 +706,13 @@
 				for i = 0; i < varargcount && it.Len() != 0; i++ {
 					m = argvar(varargtype, i)
 					varargs = append(varargs, m)
-					appendNodeSeqNode(&as.List, m)
+					as.List.Append(m)
 				}
 
 				break
 			}
 
-			appendNodeSeqNode(&as.List, tinlvar(t))
+			as.List.Append(tinlvar(t))
 		}
 	} else {
 		// match arguments except final variadic (unless the call is dotted itself)
@@ -724,7 +724,7 @@
 			if variadic && t.Isddd {
 				break
 			}
-			appendNodeSeqNode(&as.List, tinlvar(t))
+			as.List.Append(tinlvar(t))
 			t = t.Down
 			it.Next()
 		}
@@ -736,7 +736,7 @@
 			for i = 0; i < varargcount && !it.Done(); i++ {
 				m = argvar(varargtype, i)
 				varargs = append(varargs, m)
-				appendNodeSeqNode(&as.List, m)
+				as.List.Append(m)
 				it.Next()
 			}
 
@@ -750,9 +750,9 @@
 		}
 	}
 
-	if nodeSeqLen(as.Rlist) != 0 {
+	if as.Rlist.Len() != 0 {
 		typecheck(&as, Etop)
-		appendNodeSeqNode(&ninit, as)
+		ninit.Append(as)
 	}
 
 	// turn the variadic args into a slice.
@@ -767,19 +767,19 @@
 			vararrtype.Bound = int64(varargcount)
 
 			as.Right = Nod(OCOMPLIT, nil, typenod(varargtype))
-			setNodeSeq(&as.Right.List, varargs)
+			as.Right.List.Set(varargs)
 			as.Right = Nod(OSLICE, as.Right, Nod(OKEY, nil, nil))
 		}
 
 		typecheck(&as, Etop)
-		appendNodeSeqNode(&ninit, as)
+		ninit.Append(as)
 	}
 
 	// zero the outparams
 	for ll := inlretvars; ll != nil; ll = ll.Next {
 		as = Nod(OAS, ll.N, nil)
 		typecheck(&as, Etop)
-		appendNodeSeqNode(&ninit, as)
+		ninit.Append(as)
 	}
 
 	inlretlabel = newlabel_inl()
@@ -795,7 +795,7 @@
 
 	call := Nod(OINLCALL, nil, nil)
 
-	setNodeSeq(&call.Ninit, ninit)
+	call.Ninit.Set(ninit.Slice())
 	call.Nbody.Set(body)
 	setNodeSeq(&call.Rlist, inlretvars)
 	call.Type = n.Type
@@ -804,11 +804,11 @@
 	// Hide the args from setlno -- the parameters to the inlined
 	// call already have good line numbers that should be preserved.
 	args := as.Rlist
-	setNodeSeq(&as.Rlist, nil)
+	as.Rlist.Set(nil)
 
 	setlno(call, n.Lineno)
 
-	setNodeSeq(&as.Rlist, args)
+	as.Rlist.Set(args.Slice())
 
 	//dumplist("call body", body);
 
@@ -900,9 +900,9 @@
 // to input/output parameters with ones to the tmpnames, and
 // substituting returns with assignments to the output.
 func inlsubstlist(ll Nodes) []*Node {
-	s := make([]*Node, 0, nodeSeqLen(ll))
-	for it := nodeSeqIterate(ll); !it.Done(); it.Next() {
-		s = append(s, inlsubst(it.N()))
+	s := make([]*Node, 0, ll.Len())
+	for _, n := range ll.Slice() {
+		s = append(s, inlsubst(n))
 	}
 	return s
 }
@@ -935,18 +935,18 @@
 	case ORETURN:
 		m := Nod(OGOTO, inlretlabel, nil)
 
-		setNodeSeq(&m.Ninit, inlsubstlist(n.Ninit))
+		m.Ninit.Set(inlsubstlist(n.Ninit))
 
-		if inlretvars != nil && nodeSeqLen(n.List) != 0 {
+		if inlretvars != nil && n.List.Len() != 0 {
 			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 {
-				appendNodeSeqNode(&as.List, ll.N)
+				as.List.Append(ll.N)
 			}
-			setNodeSeq(&as.Rlist, inlsubstlist(n.List))
+			as.Rlist.Set(inlsubstlist(n.List))
 			typecheck(&as, Etop)
-			appendNodeSeqNode(&m.Ninit, as)
+			m.Ninit.Append(as)
 		}
 
 		typechecklist(m.Ninit.Slice(), Etop)
@@ -958,7 +958,7 @@
 	case OGOTO, OLABEL:
 		m := Nod(OXXX, nil, nil)
 		*m = *n
-		setNodeSeq(&m.Ninit, nil)
+		m.Ninit.Set(nil)
 		p := fmt.Sprintf("%s·%d", n.Left.Sym.Name, inlgen)
 		m.Left = newname(Lookup(p))
 
@@ -967,7 +967,7 @@
 
 	m := Nod(OXXX, nil, nil)
 	*m = *n
-	setNodeSeq(&m.Ninit, nil)
+	m.Ninit.Set(nil)
 
 	if n.Op == OCLOSURE {
 		Fatalf("cannot inline function containing closure: %v", Nconv(n, obj.FmtSign))
@@ -975,9 +975,9 @@
 
 	m.Left = inlsubst(n.Left)
 	m.Right = inlsubst(n.Right)
-	setNodeSeq(&m.List, inlsubstlist(n.List))
-	setNodeSeq(&m.Rlist, inlsubstlist(n.Rlist))
-	setNodeSeq(&m.Ninit, append(nodeSeqSlice(m.Ninit), inlsubstlist(n.Ninit)...))
+	m.List.Set(inlsubstlist(n.List))
+	m.Rlist.Set(inlsubstlist(n.Rlist))
+	m.Ninit.Set(append(m.Ninit.Slice(), inlsubstlist(n.Ninit)...))
 	m.Nbody.Set(inlsubstlist(n.Nbody))
 
 	return m
@@ -985,8 +985,8 @@
 
 // Plaster over linenumbers
 func setlnolist(ll Nodes, lno int32) {
-	for it := nodeSeqIterate(ll); !it.Done(); it.Next() {
-		setlno(it.N(), lno)
+	for _, n := range ll.Slice() {
+		setlno(n, lno)
 	}
 }
 
diff --git a/src/cmd/compile/internal/gc/order.go b/src/cmd/compile/internal/gc/order.go
index 7f74082..d287ae6 100644
--- a/src/cmd/compile/internal/gc/order.go
+++ b/src/cmd/compile/internal/gc/order.go
@@ -250,8 +250,8 @@
 
 // Orderstmtlist orders each of the statements in the list.
 func orderstmtlist(l Nodes, order *Order) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		orderstmt(it.N(), order)
+	for _, n := range l.Slice() {
+		orderstmt(n, order)
 	}
 }
 
@@ -304,17 +304,17 @@
 // Orderinit moves n's init list to order->out.
 func orderinit(n *Node, order *Order) {
 	orderstmtlist(n.Ninit, order)
-	setNodeSeq(&n.Ninit, nil)
+	n.Ninit.Set(nil)
 }
 
 // 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 Nodes) bool {
 	// one arg only
-	if nodeSeqLen(l) != 1 {
+	if l.Len() != 1 {
 		return false
 	}
-	n := nodeSeqFirst(l)
+	n := l.First()
 
 	// must be call
 	switch n.Op {
@@ -360,7 +360,7 @@
 func ordercallargs(l Nodes, order *Order) Nodes {
 	if ismulticall(l) {
 		// return f() where f() is multiple values.
-		return copyret(nodeSeqFirst(l), order)
+		return copyret(l.First(), order)
 	} else {
 		orderexprlist(l, order)
 		return l
@@ -443,23 +443,23 @@
 		var post []*Node
 		var m *Node
 		var a *Node
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if it.N().Op == OINDEXMAP {
-				m = it.N()
+		for i1, n1 := range n.List.Slice() {
+			if n1.Op == OINDEXMAP {
+				m = n1
 				if !istemp(m.Left) {
 					m.Left = ordercopyexpr(m.Left, m.Left.Type, order, 0)
 				}
 				if !istemp(m.Right) {
 					m.Right = ordercopyexpr(m.Right, m.Right.Type, order, 0)
 				}
-				*it.P() = ordertemp(m.Type, order, false)
-				a = Nod(OAS, m, it.N())
+				n.List.Slice()[i1] = ordertemp(m.Type, order, false)
+				a = Nod(OAS, m, n.List.Slice()[i1])
 				typecheck(&a, Etop)
 				post = append(post, a)
-			} else if instrumenting && n.Op == OAS2FUNC && !isblank(it.N()) {
-				m = it.N()
-				*it.P() = ordertemp(m.Type, order, false)
-				a = Nod(OAS, m, it.N())
+			} else if instrumenting && n.Op == OAS2FUNC && !isblank(n.List.Slice()[i1]) {
+				m = n.List.Slice()[i1]
+				n.List.Slice()[i1] = ordertemp(m.Type, order, false)
+				a = Nod(OAS, m, n.List.Slice()[i1])
 				typecheck(&a, Etop)
 				post = append(post, a)
 			}
@@ -546,7 +546,7 @@
 		t := marktemp(order)
 
 		orderexprlist(n.List, order)
-		r := nodeSeqFirst(n.Rlist)
+		r := n.Rlist.First()
 		orderexpr(&r.Left, order, nil)
 		orderexpr(&r.Right, order, nil)
 
@@ -563,7 +563,7 @@
 		t := marktemp(order)
 
 		orderexprlist(n.List, order)
-		ordercall(nodeSeqFirst(n.Rlist), order)
+		ordercall(n.Rlist.First(), order)
 		ordermapassign(n, order)
 		cleantemp(t, order)
 
@@ -574,17 +574,17 @@
 		t := marktemp(order)
 
 		orderexprlist(n.List, order)
-		orderexpr(&nodeSeqFirst(n.Rlist).Left, order, nil) // i in i.(T)
-		if isblank(nodeSeqFirst(n.List)) {
+		orderexpr(&n.Rlist.First().Left, order, nil) // i in i.(T)
+		if isblank(n.List.First()) {
 			order.out = append(order.out, n)
 		} else {
-			typ := nodeSeqFirst(n.Rlist).Type
+			typ := n.Rlist.First().Type
 			tmp1 := ordertemp(typ, order, haspointers(typ))
 			order.out = append(order.out, n)
-			r := Nod(OAS, nodeSeqFirst(n.List), tmp1)
+			r := Nod(OAS, n.List.First(), tmp1)
 			typecheck(&r, Etop)
 			ordermapassign(r, order)
-			setNodeSeq(&n.List, []*Node{tmp1, nodeSeqSecond(n.List)})
+			n.List.Set([]*Node{tmp1, n.List.Second()})
 		}
 
 		cleantemp(t, order)
@@ -595,23 +595,23 @@
 		t := marktemp(order)
 
 		orderexprlist(n.List, order)
-		orderexpr(&nodeSeqFirst(n.Rlist).Left, order, nil) // arg to recv
-		ch := nodeSeqFirst(n.Rlist).Left.Type
+		orderexpr(&n.Rlist.First().Left, order, nil) // arg to recv
+		ch := n.Rlist.First().Left.Type
 		tmp1 := ordertemp(ch.Type, order, haspointers(ch.Type))
 		var tmp2 *Node
-		if !isblank(nodeSeqSecond(n.List)) {
-			tmp2 = ordertemp(nodeSeqSecond(n.List).Type, order, false)
+		if !isblank(n.List.Second()) {
+			tmp2 = ordertemp(n.List.Second().Type, order, false)
 		} else {
 			tmp2 = ordertemp(Types[TBOOL], order, false)
 		}
 		order.out = append(order.out, n)
-		r := Nod(OAS, nodeSeqFirst(n.List), tmp1)
+		r := Nod(OAS, n.List.First(), tmp1)
 		typecheck(&r, Etop)
 		ordermapassign(r, order)
-		r = Nod(OAS, nodeSeqSecond(n.List), tmp2)
+		r = Nod(OAS, n.List.Second(), tmp2)
 		typecheck(&r, Etop)
 		ordermapassign(r, order)
-		setNodeSeq(&n.List, []*Node{tmp1, tmp2})
+		n.List.Set([]*Node{tmp1, tmp2})
 		cleantemp(t, order)
 
 		// Special: does not save n onto out.
@@ -699,10 +699,10 @@
 		n.Nbody.Set(append(l, n.Nbody.Slice()...))
 		l = nil
 		cleantempnopop(t, order, &l)
-		setNodeSeq(&n.Rlist, append(l, nodeSeqSlice(n.Rlist)...))
+		n.Rlist.Set(append(l, n.Rlist.Slice()...))
 		poptemp(t, order)
 		orderblockNodes(&n.Nbody)
-		setNodeSeq(&n.Rlist, orderblock(n.Rlist))
+		n.Rlist.Set(orderblock(n.Rlist))
 		order.out = append(order.out, n)
 
 		// Special: argument will be converted to interface using convT2E
@@ -739,7 +739,7 @@
 			if n.Right.Op == OSTRARRAYBYTE {
 				n.Right.Op = OSTRARRAYBYTETMP
 			}
-			if nodeSeqLen(n.List) < 2 || isblank(nodeSeqSecond(n.List)) {
+			if n.List.Len() < 2 || isblank(n.List.Second()) {
 				// for i := range x will only use x once, to compute len(x).
 				// No need to copy it.
 				break
@@ -771,9 +771,8 @@
 			// n->alloc is the temp for the iterator.
 			prealloc[n] = ordertemp(Types[TUINT8], order, true)
 		}
-
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			orderexprinplace(it.P(), order)
+		for i1 := range n.List.Slice() {
+			orderexprinplace(&n.List.Slice()[i1], order)
 		}
 		orderblockNodes(&n.Nbody)
 		order.out = append(order.out, n)
@@ -798,16 +797,16 @@
 		var tmp1 *Node
 		var tmp2 *Node
 		var r *Node
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if it.N().Op != OXCASE {
-				Fatalf("order select case %v", Oconv(it.N().Op, 0))
+		for _, n2 := range n.List.Slice() {
+			if n2.Op != OXCASE {
+				Fatalf("order select case %v", Oconv(n2.Op, 0))
 			}
-			r = it.N().Left
-			setlineno(it.N())
+			r = n2.Left
+			setlineno(n2)
 
 			// Append any new body prologue to ninit.
 			// The next loop will insert ninit into nbody.
-			if nodeSeqLen(it.N().Ninit) != 0 {
+			if n2.Ninit.Len() != 0 {
 				Fatalf("order select ninit")
 			}
 			if r != nil {
@@ -826,15 +825,15 @@
 						if itinit.Len() != 0 && itinit.N().Op == ODCL && itinit.N().Left == r.Left {
 							itinit.Next()
 						}
-						if itinit.Len() != 0 && itinit.N().Op == ODCL && nodeSeqLen(r.List) != 0 && itinit.N().Left == nodeSeqFirst(r.List) {
+						if itinit.Len() != 0 && itinit.N().Op == ODCL && r.List.Len() != 0 && itinit.N().Left == r.List.First() {
 							itinit.Next()
 						}
 						if itinit.Done() {
-							setNodeSeq(&r.Ninit, nil)
+							r.Ninit.Set(nil)
 						}
 					}
 
-					if nodeSeqLen(r.Ninit) != 0 {
+					if r.Ninit.Len() != 0 {
 						Yyerror("ninit on select recv")
 						dumplist("ninit", r.Ninit)
 					}
@@ -868,36 +867,35 @@
 						if r.Colas {
 							tmp2 = Nod(ODCL, tmp1, nil)
 							typecheck(&tmp2, Etop)
-							appendNodeSeqNode(&it.N().Ninit, tmp2)
+							n2.Ninit.Append(tmp2)
 						}
 
 						r.Left = ordertemp(r.Right.Left.Type.Type, order, haspointers(r.Right.Left.Type.Type))
 						tmp2 = Nod(OAS, tmp1, r.Left)
 						typecheck(&tmp2, Etop)
-						appendNodeSeqNode(&it.N().Ninit, tmp2)
+						n2.Ninit.Append(tmp2)
 					}
 
-					if nodeSeqLen(r.List) != 0 && isblank(nodeSeqFirst(r.List)) {
-						setNodeSeq(&r.List, nil)
+					if r.List.Len() != 0 && isblank(r.List.First()) {
+						r.List.Set(nil)
 					}
-					if nodeSeqLen(r.List) != 0 {
-						tmp1 = nodeSeqFirst(r.List)
+					if r.List.Len() != 0 {
+						tmp1 = r.List.First()
 						if r.Colas {
 							tmp2 = Nod(ODCL, tmp1, nil)
 							typecheck(&tmp2, Etop)
-							appendNodeSeqNode(&it.N().Ninit, tmp2)
+							n2.Ninit.Append(tmp2)
 						}
 
 						setNodeSeq(&r.List, list1(ordertemp(tmp1.Type, order, false)))
-						tmp2 = Nod(OAS, tmp1, nodeSeqFirst(r.List))
+						tmp2 = Nod(OAS, tmp1, r.List.First())
 						typecheck(&tmp2, Etop)
-						appendNodeSeqNode(&it.N().Ninit, tmp2)
+						n2.Ninit.Append(tmp2)
 					}
-
-					setNodeSeq(&it.N().Ninit, orderblock(it.N().Ninit))
+					n2.Ninit.Set(orderblock(n2.Ninit))
 
 				case OSEND:
-					if nodeSeqLen(r.Ninit) != 0 {
+					if r.Ninit.Len() != 0 {
 						Yyerror("ninit on select send")
 						dumplist("ninit", r.Ninit)
 					}
@@ -916,17 +914,16 @@
 				}
 			}
 
-			orderblockNodes(&it.N().Nbody)
+			orderblockNodes(&n2.Nbody)
 		}
-
 		// 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 it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			s := nodeSeqSlice(it.N().Ninit)
+		for _, n3 := range n.List.Slice() {
+			s := n3.Ninit.Slice()
 			cleantempnopop(t, order, &s)
-			it.N().Nbody.Set(append(s, it.N().Nbody.Slice()...))
-			setNodeSeq(&it.N().Ninit, nil)
+			n3.Nbody.Set(append(s, n3.Nbody.Slice()...))
+			n3.Ninit.Set(nil)
 		}
 
 		order.out = append(order.out, n)
@@ -953,12 +950,12 @@
 		t := marktemp(order)
 
 		orderexpr(&n.Left, order, nil)
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if it.N().Op != OXCASE {
-				Fatalf("order switch case %v", Oconv(it.N().Op, 0))
+		for _, n4 := range n.List.Slice() {
+			if n4.Op != OXCASE {
+				Fatalf("order switch case %v", Oconv(n4.Op, 0))
 			}
-			orderexprlistinplace(it.N().List, order)
-			orderblockNodes(&it.N().Nbody)
+			orderexprlistinplace(n4.List, order)
+			orderblockNodes(&n4.Nbody)
 		}
 
 		order.out = append(order.out, n)
@@ -970,16 +967,16 @@
 
 // Orderexprlist orders the expression list l into order.
 func orderexprlist(l Nodes, order *Order) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		orderexpr(it.P(), order, nil)
+	for i := range l.Slice() {
+		orderexpr(&l.Slice()[i], order, nil)
 	}
 }
 
 // Orderexprlist orders the expression list l but saves
 // the side effects on the individual expression ninit lists.
 func orderexprlistinplace(l Nodes, order *Order) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		orderexprinplace(it.P(), order)
+	for i := range l.Slice() {
+		orderexprinplace(&l.Slice()[i], order)
 	}
 }
 
@@ -1013,9 +1010,9 @@
 	case OADDSTR:
 		orderexprlist(n.List, order)
 
-		if nodeSeqLen(n.List) > 5 {
+		if n.List.Len() > 5 {
 			t := typ(TARRAY)
-			t.Bound = int64(nodeSeqLen(n.List))
+			t.Bound = int64(n.List.Len())
 			t.Type = Types[TSTRING]
 			prealloc[n] = ordertemp(t, order, false)
 		}
@@ -1030,15 +1027,15 @@
 		hasbyte := false
 
 		haslit := false
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			hasbyte = hasbyte || it.N().Op == OARRAYBYTESTR
-			haslit = haslit || it.N().Op == OLITERAL && len(it.N().Val().U.(string)) != 0
+		for _, n1 := range n.List.Slice() {
+			hasbyte = hasbyte || n1.Op == OARRAYBYTESTR
+			haslit = haslit || n1.Op == OLITERAL && len(n1.Val().U.(string)) != 0
 		}
 
 		if haslit && hasbyte {
-			for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-				if it.N().Op == OARRAYBYTESTR {
-					it.N().Op = OARRAYBYTESTRTMP
+			for _, n2 := range n.List.Slice() {
+				if n2.Op == OARRAYBYTESTR {
+					n2.Op = OARRAYBYTESTRTMP
 				}
 			}
 		}
@@ -1103,7 +1100,7 @@
 		var s []*Node
 
 		cleantempnopop(mark, order, &s)
-		setNodeSeq(&n.Right.Ninit, append(s, nodeSeqSlice(n.Right.Ninit)...))
+		n.Right.Ninit.Set(append(s, n.Right.Ninit.Slice()...))
 		orderexprinplace(&n.Right, order)
 
 	case OCALLFUNC,
@@ -1130,7 +1127,7 @@
 
 	case OAPPEND:
 		setNodeSeq(&n.List, ordercallargs(n.List, order))
-		if lhs == nil || lhs.Op != ONAME && !samesafeexpr(lhs, nodeSeqFirst(n.List)) {
+		if lhs == nil || lhs.Op != ONAME && !samesafeexpr(lhs, n.List.First()) {
 			n = ordercopyexpr(n, n.Type, order, 0)
 		}
 
diff --git a/src/cmd/compile/internal/gc/parser.go b/src/cmd/compile/internal/gc/parser.go
index 9a5dfe9..6312756 100644
--- a/src/cmd/compile/internal/gc/parser.go
+++ b/src/cmd/compile/internal/gc/parser.go
@@ -684,7 +684,7 @@
 	label.Name.Defn = ls
 	l := []*Node{label}
 	if ls != nil {
-		if ls.Op == OBLOCK && nodeSeqLen(ls.Ninit) == 0 {
+		if ls.Op == OBLOCK && ls.Ninit.Len() == 0 {
 			l = append(l, ls.List.Slice()...)
 		} else {
 			l = append(l, ls)
@@ -726,7 +726,7 @@
 					// type switch - declare variable
 					nn := newname(n.Sym)
 					declare(nn, dclcontext)
-					setNodeSeq(&stmt.Rlist, []*Node{nn})
+					stmt.Rlist.Set([]*Node{nn})
 
 					// keep track of the instances for reporting unused
 					nn.Name.Defn = tswitch
@@ -752,9 +752,9 @@
 			} else {
 				n = Nod(OAS2, nil, nil)
 				setNodeSeq(&n.List, cases)
-				setNodeSeq(&n.Rlist, []*Node{rhs})
+				n.Rlist.Set([]*Node{rhs})
 			}
-			setNodeSeq(&stmt.List, []*Node{n})
+			stmt.List.Set([]*Node{n})
 
 			p.want(':') // consume ':' after declaring select cases for correct lineno
 			return stmt
@@ -770,7 +770,7 @@
 			// done in casebody()
 			markdcl() // matching popdcl in caseblock
 			stmt := Nod(OXCASE, nil, nil)
-			setNodeSeq(&stmt.List, []*Node{colas(cases, list1(rhs), lno)})
+			stmt.List.Set([]*Node{colas(cases, list1(rhs), lno)})
 
 			p.want(':') // consume ':' after declaring select cases for correct lineno
 			return stmt
@@ -794,7 +794,7 @@
 				// type switch - declare variable
 				nn := newname(n.Sym)
 				declare(nn, dclcontext)
-				setNodeSeq(&stmt.Rlist, []*Node{nn})
+				stmt.Rlist.Set([]*Node{nn})
 
 				// keep track of the instances for reporting unused
 				nn.Name.Defn = tswitch
@@ -918,7 +918,7 @@
 		}
 		h := Nod(OFOR, nil, nil)
 		if init != nil {
-			setNodeSeq(&h.Ninit, []*Node{init})
+			h.Ninit.Set([]*Node{init})
 		}
 		h.Left = cond
 		h.Right = post
@@ -1022,7 +1022,7 @@
 	init, cond, _ := p.header(false)
 	h := Nod(OIF, nil, nil)
 	if init != nil {
-		setNodeSeq(&h.Ninit, []*Node{init})
+		h.Ninit.Set([]*Node{init})
 	}
 	h.Left = cond
 	return h
@@ -1047,13 +1047,13 @@
 
 	if p.got(LELSE) {
 		if p.tok == LIF {
-			setNodeSeq(&stmt.Rlist, []*Node{p.if_stmt()})
+			stmt.Rlist.Set([]*Node{p.if_stmt()})
 		} else {
 			cs := p.compound_stmt(true)
-			if cs.Op == OBLOCK && nodeSeqLen(cs.Ninit) == 0 {
-				setNodeSeq(&stmt.Rlist, cs.List)
+			if cs.Op == OBLOCK && cs.Ninit.Len() == 0 {
+				stmt.Rlist.Set(cs.List.Slice())
 			} else {
-				setNodeSeq(&stmt.Rlist, []*Node{cs})
+				stmt.Rlist.Set([]*Node{cs})
 			}
 		}
 	}
@@ -1553,7 +1553,7 @@
 	p.xnest--
 	p.want('}')
 
-	setNodeSeq(&n.List, l)
+	n.List.Set(l)
 	return n
 }
 
@@ -1842,7 +1842,7 @@
 	p.want('}')
 
 	t := Nod(OTINTER, nil, nil)
-	setNodeSeq(&t.List, l)
+	t.List.Set(l)
 	return t
 }
 
@@ -2514,7 +2514,7 @@
 
 		stmt := Nod(ORETURN, nil, nil)
 		setNodeSeq(&stmt.List, results)
-		if nodeSeqLen(stmt.List) == 0 && Curfn != nil {
+		if stmt.List.Len() == 0 && Curfn != nil {
 			for _, ln := range Curfn.Func.Dcl {
 				if ln.Class == PPARAM {
 					continue
@@ -2549,7 +2549,7 @@
 		if s == missing_stmt {
 			break
 		}
-		if s != nil && s.Op == OBLOCK && nodeSeqLen(s.Ninit) == 0 {
+		if s != nil && s.Op == OBLOCK && s.Ninit.Len() == 0 {
 			appendNodeSeq(&l, s.List)
 		} else {
 			appendNodeSeqNode(&l, s)
diff --git a/src/cmd/compile/internal/gc/racewalk.go b/src/cmd/compile/internal/gc/racewalk.go
index ab08405..04afc587 100644
--- a/src/cmd/compile/internal/gc/racewalk.go
+++ b/src/cmd/compile/internal/gc/racewalk.go
@@ -87,11 +87,11 @@
 }
 
 func instrumentlist(l Nodes, init *Nodes) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
+	for i := range l.Slice() {
 		var instr Nodes
-		instrumentnode(it.P(), &instr, 0, 0)
+		instrumentnode(&l.Slice()[i], &instr, 0, 0)
 		if init == nil {
-			it.N().Ninit.AppendNodes(&instr)
+			l.Slice()[i].Ninit.AppendNodes(&instr)
 		} else {
 			init.AppendNodes(&instr)
 		}
@@ -121,7 +121,7 @@
 		// nil it out and handle it separately before putting it back.
 		l := n.Ninit
 
-		setNodeSeq(&n.Ninit, nil)
+		n.Ninit.Set(nil)
 		instrumentlist(l, nil)
 		instrumentnode(&n, &l, wr, skip) // recurse with nil n->ninit
 		appendinit(&n, l)
@@ -167,7 +167,7 @@
 				out = append(outn.Slice(), it.N())
 			}
 		}
-		setNodeSeq(&n.List, out)
+		n.List.Set(out)
 		goto ret
 
 	case ODEFER:
@@ -595,8 +595,8 @@
 }
 
 func foreachlist(l Nodes, f func(*Node, interface{}), c interface{}) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		foreachnode(it.N(), f, c)
+	for _, n := range l.Slice() {
+		foreachnode(n, f, c)
 	}
 }
 
@@ -619,7 +619,7 @@
 // appendinit is like addinit in subr.go
 // but appends rather than prepends.
 func appendinit(np **Node, init Nodes) {
-	if nodeSeqLen(init) == 0 {
+	if init.Len() == 0 {
 		return
 	}
 
@@ -635,6 +635,6 @@
 		*np = n
 	}
 
-	appendNodeSeq(&n.Ninit, init)
+	n.Ninit.AppendNodes(&init)
 	n.Ullman = UINF
 }
diff --git a/src/cmd/compile/internal/gc/range.go b/src/cmd/compile/internal/gc/range.go
index 43447b459..841c95b 100644
--- a/src/cmd/compile/internal/gc/range.go
+++ b/src/cmd/compile/internal/gc/range.go
@@ -31,11 +31,10 @@
 	if t == nil {
 		goto out
 	}
-
 	// delicate little dance.  see typecheckas2
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		if it.N().Name == nil || it.N().Name.Defn != n {
-			typecheck(it.P(), Erv|Easgn)
+	for i1, n1 := range n.List.Slice() {
+		if n1.Name == nil || n1.Name.Defn != n {
+			typecheck(&n.List.Slice()[i1], Erv|Easgn)
 		}
 	}
 
@@ -66,7 +65,7 @@
 
 		t1 = t.Type
 		t2 = nil
-		if nodeSeqLen(n.List) == 2 {
+		if n.List.Len() == 2 {
 			toomany = 1
 		}
 
@@ -75,17 +74,17 @@
 		t2 = runetype
 	}
 
-	if nodeSeqLen(n.List) > 2 || toomany != 0 {
+	if n.List.Len() > 2 || toomany != 0 {
 		Yyerror("too many variables in range")
 	}
 
 	v1 = nil
-	if nodeSeqLen(n.List) != 0 {
-		v1 = nodeSeqFirst(n.List)
+	if n.List.Len() != 0 {
+		v1 = n.List.First()
 	}
 	v2 = nil
-	if nodeSeqLen(n.List) > 1 {
-		v2 = nodeSeqSecond(n.List)
+	if n.List.Len() > 1 {
+		v2 = n.List.Second()
 	}
 
 	// this is not only a optimization but also a requirement in the spec.
@@ -94,7 +93,7 @@
 	// present."
 	if isblank(v2) {
 		if v1 != nil {
-			setNodeSeq(&n.List, []*Node{v1})
+			n.List.Set([]*Node{v1})
 		}
 		v2 = nil
 	}
@@ -120,10 +119,9 @@
 	// second half of dance
 out:
 	n.Typecheck = 1
-
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		if it.N().Typecheck == 0 {
-			typecheck(it.P(), Erv|Easgn)
+	for i2, n2 := range n.List.Slice() {
+		if n2.Typecheck == 0 {
+			typecheck(&n.List.Slice()[i2], Erv|Easgn)
 		}
 	}
 
@@ -147,17 +145,17 @@
 	n.Right = nil
 
 	var v1 *Node
-	if nodeSeqLen(n.List) != 0 {
-		v1 = nodeSeqFirst(n.List)
+	if n.List.Len() != 0 {
+		v1 = n.List.First()
 	}
 	var v2 *Node
-	if nodeSeqLen(n.List) > 1 && !isblank(nodeSeqSecond(n.List)) {
-		v2 = nodeSeqSecond(n.List)
+	if n.List.Len() > 1 && !isblank(n.List.Second()) {
+		v2 = n.List.Second()
 	}
 
 	// n->list has no meaning anymore, clear it
 	// to avoid erroneous processing by racewalk.
-	setNodeSeq(&n.List, nil)
+	n.List.Set(nil)
 
 	var body []*Node
 	var init []*Node
@@ -195,8 +193,8 @@
 			body = []*Node{Nod(OAS, v1, hv1)}
 		} else {
 			a := Nod(OAS2, nil, nil)
-			setNodeSeq(&a.List, []*Node{v1, v2})
-			setNodeSeq(&a.Rlist, []*Node{hv1, Nod(OIND, hp, nil)})
+			a.List.Set([]*Node{v1, v2})
+			a.Rlist.Set([]*Node{hv1, Nod(OIND, hp, nil)})
 			body = []*Node{a}
 
 			// Advance pointer as part of increment.
@@ -215,7 +213,7 @@
 			tmp.Right.Typecheck = 1
 			a = Nod(OAS, hp, tmp)
 			typecheck(&a, Etop)
-			setNodeSeq(&n.Right.Ninit, []*Node{a})
+			n.Right.Ninit.Set([]*Node{a})
 		}
 
 		// orderstmt allocated the iterator for us.
@@ -250,8 +248,8 @@
 			val := Nod(ODOT, hit, valname)
 			val = Nod(OIND, val, nil)
 			a := Nod(OAS2, nil, nil)
-			setNodeSeq(&a.List, []*Node{v1, v2})
-			setNodeSeq(&a.Rlist, []*Node{key, val})
+			a.List.Set([]*Node{v1, v2})
+			a.Rlist.Set([]*Node{key, val})
 			body = []*Node{a}
 		}
 
@@ -271,9 +269,9 @@
 		n.Left = Nod(ONE, hb, Nodbool(false))
 		a := Nod(OAS2RECV, nil, nil)
 		a.Typecheck = 1
-		setNodeSeq(&a.List, []*Node{hv1, hb})
-		setNodeSeq(&a.Rlist, []*Node{Nod(ORECV, ha, nil)})
-		setNodeSeq(&n.Left.Ninit, []*Node{a})
+		a.List.Set([]*Node{hv1, hb})
+		a.Rlist.Set([]*Node{Nod(ORECV, ha, nil)})
+		n.Left.Ninit.Set([]*Node{a})
 		if v1 == nil {
 			body = nil
 		} else {
@@ -296,13 +294,13 @@
 		} else {
 			hv2 = temp(runetype)
 			a = Nod(OAS2, nil, nil)
-			setNodeSeq(&a.List, []*Node{hv1, hv2})
+			a.List.Set([]*Node{hv1, hv2})
 			fn := syslook("stringiter2")
-			setNodeSeq(&a.Rlist, []*Node{mkcall1(fn, fn.Type.Results(), nil, ha, hv1)})
+			a.Rlist.Set([]*Node{mkcall1(fn, fn.Type.Results(), nil, ha, hv1)})
 		}
 
 		n.Left = Nod(ONE, hv1, Nodintconst(0))
-		setNodeSeq(&n.Left.Ninit, []*Node{Nod(OAS, ohv1, hv1), a})
+		n.Left.Ninit.Set([]*Node{Nod(OAS, ohv1, hv1), a})
 
 		body = nil
 		if v1 != nil {
@@ -315,7 +313,7 @@
 
 	n.Op = OFOR
 	typechecklist(init, Etop)
-	appendNodeSeq(&n.Ninit, init)
+	n.Ninit.Append(init...)
 	typechecklist(n.Left.Ninit.Slice(), Etop)
 	typecheck(&n.Left, Erv)
 	typecheck(&n.Right, Etop)
diff --git a/src/cmd/compile/internal/gc/select.go b/src/cmd/compile/internal/gc/select.go
index 16d7575..91cb086 100644
--- a/src/cmd/compile/internal/gc/select.go
+++ b/src/cmd/compile/internal/gc/select.go
@@ -13,28 +13,28 @@
 	lno := setlineno(sel)
 	count := 0
 	typechecklist(sel.Ninit.Slice(), Etop)
-	for it := nodeSeqIterate(sel.List); !it.Done(); it.Next() {
+	for _, n1 := range sel.List.Slice() {
 		count++
-		ncase = it.N()
+		ncase = n1
 		setlineno(ncase)
 		if ncase.Op != OXCASE {
 			Fatalf("typecheckselect %v", Oconv(ncase.Op, 0))
 		}
 
-		if nodeSeqLen(ncase.List) == 0 {
+		if ncase.List.Len() == 0 {
 			// default
 			if def != nil {
 				Yyerror("multiple defaults in select (first at %v)", def.Line())
 			} else {
 				def = ncase
 			}
-		} else if nodeSeqLen(ncase.List) > 1 {
+		} else if ncase.List.Len() > 1 {
 			Yyerror("select cases cannot be lists")
 		} else {
 			it2 := nodeSeqIterate(ncase.List)
 			n = typecheck(it2.P(), Etop)
 			ncase.Left = n
-			setNodeSeq(&ncase.List, nil)
+			ncase.List.Set(nil)
 			setlineno(n)
 			switch n.Op {
 			default:
@@ -57,16 +57,16 @@
 
 				// convert x, ok = <-c into OSELRECV2(x, <-c) with ntest=ok
 			case OAS2RECV:
-				if nodeSeqFirst(n.Rlist).Op != ORECV {
+				if n.Rlist.First().Op != ORECV {
 					Yyerror("select assignment must have receive on right hand side")
 					break
 				}
 
 				n.Op = OSELRECV2
-				n.Left = nodeSeqFirst(n.List)
-				setNodeSeq(&n.List, []*Node{nodeSeqSecond(n.List)})
-				n.Right = nodeSeqFirst(n.Rlist)
-				setNodeSeq(&n.Rlist, nil)
+				n.Left = n.List.First()
+				n.List.Set([]*Node{n.List.Second()})
+				n.Right = n.Rlist.First()
+				n.Rlist.Set(nil)
 
 				// convert <-c into OSELRECV(N, <-c)
 			case ORECV:
@@ -88,12 +88,12 @@
 }
 
 func walkselect(sel *Node) {
-	if nodeSeqLen(sel.List) == 0 && sel.Xoffset != 0 {
+	if sel.List.Len() == 0 && sel.Xoffset != 0 {
 		Fatalf("double walkselect") // already rewrote
 	}
 
 	lno := setlineno(sel)
-	i := nodeSeqLen(sel.List)
+	i := sel.List.Len()
 
 	// optimization: zero-case select
 	var init []*Node
@@ -111,13 +111,13 @@
 	// TODO(rsc): Reenable optimization once order.go can handle it.
 	// golang.org/issue/7672.
 	if i == 1 {
-		cas := nodeSeqFirst(sel.List)
+		cas := sel.List.First()
 		setlineno(cas)
-		l := nodeSeqSlice(cas.Ninit)
+		l := cas.Ninit.Slice()
 		if cas.Left != nil { // not default:
 			n := cas.Left
-			l = append(l, nodeSeqSlice(n.Ninit)...)
-			setNodeSeq(&n.Ninit, nil)
+			l = append(l, n.Ninit.Slice()...)
+			n.Ninit.Set(nil)
 			var ch *Node
 			switch n.Op {
 			default:
@@ -129,7 +129,7 @@
 
 			case OSELRECV, OSELRECV2:
 				ch = n.Right.Left
-				if n.Op == OSELRECV || nodeSeqLen(n.List) == 0 {
+				if n.Op == OSELRECV || n.List.Len() == 0 {
 					if n.Left == nil {
 						n = n.Right
 					} else {
@@ -144,8 +144,8 @@
 				}
 
 				n.Op = OAS2
-				setNodeSeq(&n.List, append([]*Node{n.Left}, nodeSeqSlice(n.List)...))
-				setNodeSeq(&n.Rlist, []*Node{n.Right})
+				n.List.Set(append([]*Node{n.Left}, n.List.Slice()...))
+				n.Rlist.Set([]*Node{n.Right})
 				n.Right = nil
 				n.Left = nil
 				n.Typecheck = 0
@@ -185,7 +185,7 @@
 			typecheck(&n.Right, Erv)
 
 		case OSELRECV, OSELRECV2:
-			if n.Op == OSELRECV2 && nodeSeqLen(n.List) == 0 {
+			if n.Op == OSELRECV2 && n.List.Len() == 0 {
 				n.Op = OSELRECV
 			}
 			if n.Op == OSELRECV2 {
@@ -204,21 +204,21 @@
 	}
 
 	// optimization: two-case select but one is default: single non-blocking op.
-	if i == 2 && (nodeSeqFirst(sel.List).Left == nil || nodeSeqSecond(sel.List).Left == nil) {
+	if i == 2 && (sel.List.First().Left == nil || sel.List.Second().Left == nil) {
 		var cas *Node
 		var dflt *Node
-		if nodeSeqFirst(sel.List).Left == nil {
-			cas = nodeSeqSecond(sel.List)
-			dflt = nodeSeqFirst(sel.List)
+		if sel.List.First().Left == nil {
+			cas = sel.List.Second()
+			dflt = sel.List.First()
 		} else {
-			dflt = nodeSeqSecond(sel.List)
+			dflt = sel.List.Second()
 			cas = nodeSeqFirst(sel.List.Slice())
 		}
 
 		n := cas.Left
 		setlineno(n)
 		r := Nod(OIF, nil, nil)
-		setNodeSeq(&r.Ninit, cas.Ninit)
+		r.Ninit.Set(cas.Ninit.Slice())
 		switch n.Op {
 		default:
 			Fatalf("select %v", Oconv(n.Op, 0))
@@ -233,7 +233,7 @@
 		case OSELRECV:
 			r = Nod(OIF, nil, nil)
 
-			setNodeSeq(&r.Ninit, cas.Ninit)
+			r.Ninit.Set(cas.Ninit.Slice())
 			ch := n.Right.Left
 			r.Left = mkcall1(chanfn("selectnbrecv", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, ch)
 
@@ -241,20 +241,20 @@
 		case OSELRECV2:
 			r = Nod(OIF, nil, nil)
 
-			setNodeSeq(&r.Ninit, cas.Ninit)
+			r.Ninit.Set(cas.Ninit.Slice())
 			ch := n.Right.Left
-			r.Left = mkcall1(chanfn("selectnbrecv2", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, nodeSeqFirst(n.List), ch)
+			r.Left = mkcall1(chanfn("selectnbrecv2", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, n.List.First(), ch)
 		}
 
 		typecheck(&r.Left, Erv)
 		r.Nbody.Set(cas.Nbody.Slice())
-		setNodeSeq(&r.Rlist, append(nodeSeqSlice(dflt.Ninit), dflt.Nbody.Slice()...))
+		r.Rlist.Set(append(dflt.Ninit.Slice(), dflt.Nbody.Slice()...))
 		sel.Nbody.Set([]*Node{r})
 		goto out
 	}
 
-	init = nodeSeqSlice(sel.Ninit)
-	setNodeSeq(&sel.Ninit, nil)
+	init = sel.Ninit.Slice()
+	sel.Ninit.Set(nil)
 
 	// generate sel-struct
 	setlineno(sel)
@@ -267,18 +267,16 @@
 	r = mkcall("newselect", nil, nil, var_, Nodintconst(selv.Type.Width), Nodintconst(sel.Xoffset))
 	typecheck(&r, Etop)
 	init = append(init, r)
-
 	// register cases
-	for it := nodeSeqIterate(sel.List); !it.Done(); it.Next() {
-		cas = it.N()
+	for _, cas = range sel.List.Slice() {
 		setlineno(cas)
 		n = cas.Left
 		r = Nod(OIF, nil, nil)
-		setNodeSeq(&r.Ninit, cas.Ninit)
-		setNodeSeq(&cas.Ninit, nil)
+		r.Ninit.Set(cas.Ninit.Slice())
+		cas.Ninit.Set(nil)
 		if n != nil {
-			appendNodeSeq(&r.Ninit, n.Ninit)
-			setNodeSeq(&n.Ninit, nil)
+			r.Ninit.AppendNodes(&n.Ninit)
+			n.Ninit.Set(nil)
 		}
 
 		if n == nil {
@@ -299,7 +297,7 @@
 
 				// selectrecv2(sel *byte, hchan *chan any, elem *any, received *bool) (selected bool);
 			case OSELRECV2:
-				r.Left = mkcall1(chanfn("selectrecv2", 2, n.Right.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Right.Left, n.Left, nodeSeqFirst(n.List))
+				r.Left = mkcall1(chanfn("selectrecv2", 2, n.Right.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Right.Left, n.Left, n.List.First())
 			}
 		}
 
@@ -318,7 +316,7 @@
 	sel.Nbody.Set(init)
 
 out:
-	setNodeSeq(&sel.List, nil)
+	sel.List.Set(nil)
 	walkstmtlist(sel.Nbody.Slice())
 	lineno = lno
 }
@@ -329,41 +327,41 @@
 	// and then cache; and also cache Select per size.
 	sudog := Nod(OTSTRUCT, nil, nil)
 
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("g")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("selectdone")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("next")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("prev")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("elem")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("releasetime")), typenod(Types[TUINT64])))
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("nrelease")), typenod(Types[TINT32])))
-	appendNodeSeqNode(&sudog.List, Nod(ODCLFIELD, newname(Lookup("waitlink")), typenod(Ptrto(Types[TUINT8]))))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("g")), typenod(Ptrto(Types[TUINT8]))))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("selectdone")), typenod(Ptrto(Types[TUINT8]))))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("next")), typenod(Ptrto(Types[TUINT8]))))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("prev")), typenod(Ptrto(Types[TUINT8]))))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("elem")), typenod(Ptrto(Types[TUINT8]))))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("releasetime")), typenod(Types[TUINT64])))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("nrelease")), typenod(Types[TINT32])))
+	sudog.List.Append(Nod(ODCLFIELD, newname(Lookup("waitlink")), typenod(Ptrto(Types[TUINT8]))))
 	typecheck(&sudog, Etype)
 	sudog.Type.Noalg = true
 	sudog.Type.Local = true
 
 	scase := Nod(OTSTRUCT, nil, nil)
-	appendNodeSeqNode(&scase.List, Nod(ODCLFIELD, newname(Lookup("elem")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&scase.List, Nod(ODCLFIELD, newname(Lookup("chan")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&scase.List, Nod(ODCLFIELD, newname(Lookup("pc")), typenod(Types[TUINTPTR])))
-	appendNodeSeqNode(&scase.List, Nod(ODCLFIELD, newname(Lookup("kind")), typenod(Types[TUINT16])))
-	appendNodeSeqNode(&scase.List, Nod(ODCLFIELD, newname(Lookup("so")), typenod(Types[TUINT16])))
-	appendNodeSeqNode(&scase.List, Nod(ODCLFIELD, newname(Lookup("receivedp")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&scase.List, Nod(ODCLFIELD, newname(Lookup("releasetime")), typenod(Types[TUINT64])))
+	scase.List.Append(Nod(ODCLFIELD, newname(Lookup("elem")), typenod(Ptrto(Types[TUINT8]))))
+	scase.List.Append(Nod(ODCLFIELD, newname(Lookup("chan")), typenod(Ptrto(Types[TUINT8]))))
+	scase.List.Append(Nod(ODCLFIELD, newname(Lookup("pc")), typenod(Types[TUINTPTR])))
+	scase.List.Append(Nod(ODCLFIELD, newname(Lookup("kind")), typenod(Types[TUINT16])))
+	scase.List.Append(Nod(ODCLFIELD, newname(Lookup("so")), typenod(Types[TUINT16])))
+	scase.List.Append(Nod(ODCLFIELD, newname(Lookup("receivedp")), typenod(Ptrto(Types[TUINT8]))))
+	scase.List.Append(Nod(ODCLFIELD, newname(Lookup("releasetime")), typenod(Types[TUINT64])))
 	typecheck(&scase, Etype)
 	scase.Type.Noalg = true
 	scase.Type.Local = true
 
 	sel := Nod(OTSTRUCT, nil, nil)
-	appendNodeSeqNode(&sel.List, Nod(ODCLFIELD, newname(Lookup("tcase")), typenod(Types[TUINT16])))
-	appendNodeSeqNode(&sel.List, Nod(ODCLFIELD, newname(Lookup("ncase")), typenod(Types[TUINT16])))
-	appendNodeSeqNode(&sel.List, Nod(ODCLFIELD, newname(Lookup("pollorder")), typenod(Ptrto(Types[TUINT8]))))
-	appendNodeSeqNode(&sel.List, Nod(ODCLFIELD, newname(Lookup("lockorder")), typenod(Ptrto(Types[TUINT8]))))
+	sel.List.Append(Nod(ODCLFIELD, newname(Lookup("tcase")), typenod(Types[TUINT16])))
+	sel.List.Append(Nod(ODCLFIELD, newname(Lookup("ncase")), typenod(Types[TUINT16])))
+	sel.List.Append(Nod(ODCLFIELD, newname(Lookup("pollorder")), typenod(Ptrto(Types[TUINT8]))))
+	sel.List.Append(Nod(ODCLFIELD, newname(Lookup("lockorder")), typenod(Ptrto(Types[TUINT8]))))
 	arr := Nod(OTARRAY, Nodintconst(int64(size)), scase)
-	appendNodeSeqNode(&sel.List, Nod(ODCLFIELD, newname(Lookup("scase")), arr))
+	sel.List.Append(Nod(ODCLFIELD, newname(Lookup("scase")), arr))
 	arr = Nod(OTARRAY, Nodintconst(int64(size)), typenod(Ptrto(Types[TUINT8])))
-	appendNodeSeqNode(&sel.List, Nod(ODCLFIELD, newname(Lookup("lockorderarr")), arr))
+	sel.List.Append(Nod(ODCLFIELD, newname(Lookup("lockorderarr")), arr))
 	arr = Nod(OTARRAY, Nodintconst(int64(size)), typenod(Types[TUINT16]))
-	appendNodeSeqNode(&sel.List, Nod(ODCLFIELD, newname(Lookup("pollorderarr")), arr))
+	sel.List.Append(Nod(ODCLFIELD, newname(Lookup("pollorderarr")), arr))
 	typecheck(&sel, Etype)
 	sel.Type.Noalg = true
 	sel.Type.Local = true
diff --git a/src/cmd/compile/internal/gc/sinit.go b/src/cmd/compile/internal/gc/sinit.go
index a0ec4cc..4b73001 100644
--- a/src/cmd/compile/internal/gc/sinit.go
+++ b/src/cmd/compile/internal/gc/sinit.go
@@ -30,8 +30,8 @@
 	}
 	init1(n.Left, out)
 	init1(n.Right, out)
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		init1(it.N(), out)
+	for _, n1 := range n.List.Slice() {
+		init1(n1, out)
 	}
 
 	if n.Left != nil && n.Type != nil && n.Left.Op == OTYPE && n.Class == PFUNC {
@@ -128,8 +128,8 @@
 				break
 			}
 			defn.Initorder = InitPending
-			for it := nodeSeqIterate(defn.Rlist); !it.Done(); it.Next() {
-				init1(it.N(), out)
+			for _, n2 := range defn.Rlist.Slice() {
+				init1(n2, out)
 			}
 			if Debug['%'] != 0 {
 				Dump("nonstatic", defn)
@@ -192,7 +192,7 @@
 		return
 	}
 
-	if n.Op == ONAME && nodeSeqLen(n.Ninit) != 0 {
+	if n.Op == ONAME && n.Ninit.Len() != 0 {
 		Fatalf("name %v with ninit: %v\n", n.Sym, Nconv(n, obj.FmtSign))
 	}
 
@@ -213,23 +213,21 @@
 }
 
 func init2list(l Nodes, out *[]*Node) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		init2(it.N(), out)
+	for _, n := range l.Slice() {
+		init2(n, out)
 	}
 }
 
 func initreorder(l []*Node, out *[]*Node) {
 	var n *Node
-
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		n = it.N()
+	for _, n = range l {
 		switch n.Op {
 		case ODCLFUNC, ODCLCONST, ODCLTYPE:
 			continue
 		}
 
 		initreorder(n.Ninit.Slice(), out)
-		setNodeSeq(&n.Ninit, nil)
+		n.Ninit.Set(nil)
 		init1(n, out)
 	}
 }
@@ -558,9 +556,8 @@
 	case OSTRUCTLIT:
 		break
 	}
-
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		value := it.N().Right
+	for _, n1 := range n.List.Slice() {
+		value := n1.Right
 		mode |= getdyn(value, 0)
 		if mode == MODEDYNAM|MODECONST {
 			break
@@ -571,8 +568,7 @@
 }
 
 func structlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		r := it.N()
+	for _, r := range n.List.Slice() {
 		if r.Op != OKEY {
 			Fatalf("structlit: rhs not OKEY: %v", r)
 		}
@@ -636,8 +632,7 @@
 }
 
 func arraylit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		r := it.N()
+	for _, r := range n.List.Slice() {
 		if r.Op != OKEY {
 			Fatalf("arraylit: rhs not OKEY: %v", r)
 		}
@@ -784,7 +779,7 @@
 		a = Nod(OADDR, a, nil)
 	} else {
 		a = Nod(ONEW, nil, nil)
-		setNodeSeq(&a.List, []*Node{typenod(t)})
+		a.List.Set([]*Node{typenod(t)})
 	}
 
 	a = Nod(OAS, vauto, a)
@@ -809,10 +804,8 @@
 	orderstmtinplace(&a)
 	walkstmt(&a)
 	init.Append(a)
-
 	// put dynamics into slice (6)
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		r := it.N()
+	for _, r := range n.List.Slice() {
 		if r.Op != OKEY {
 			Fatalf("slicelit: rhs not OKEY: %v", r)
 		}
@@ -858,13 +851,12 @@
 	nerr := nerrors
 
 	a := Nod(OMAKE, nil, nil)
-	setNodeSeq(&a.List, []*Node{typenod(n.Type)})
+	a.List.Set([]*Node{typenod(n.Type)})
 	litas(var_, a, init)
 
 	// count the initializers
 	b := 0
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		r := it.N()
+	for _, r := range n.List.Slice() {
 		if r.Op != OKEY {
 			Fatalf("maplit: rhs not OKEY: %v", r)
 		}
@@ -907,9 +899,7 @@
 		vstat := staticname(tarr, ctxt)
 
 		b := int64(0)
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			r := it.N()
-
+		for _, r := range n.List.Slice() {
 			if r.Op != OKEY {
 				Fatalf("maplit: rhs not OKEY: %v", r)
 			}
@@ -965,7 +955,7 @@
 		a = Nod(OFOR, nil, nil)
 		a.Nbody.Set([]*Node{r})
 
-		setNodeSeq(&a.Ninit, []*Node{Nod(OAS, index, Nodintconst(0))})
+		a.Ninit.Set([]*Node{Nod(OAS, index, Nodintconst(0))})
 		a.Left = Nod(OLT, index, Nodintconst(tarr.Bound))
 		a.Right = Nod(OAS, index, Nod(OADD, index, Nodintconst(1)))
 
@@ -976,9 +966,7 @@
 
 	// put in dynamic entries one-at-a-time
 	var key, val *Node
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		r := it.N()
-
+	for _, r := range n.List.Slice() {
 		if r.Op != OKEY {
 			Fatalf("maplit: rhs not OKEY: %v", r)
 		}
@@ -1065,7 +1053,7 @@
 			Fatalf("anylit: not struct")
 		}
 
-		if simplename(var_) && nodeSeqLen(n.List) > 4 {
+		if simplename(var_) && n.List.Len() > 4 {
 			if ctxt == 0 {
 				// lay out static data
 				vstat := staticname(t, ctxt)
@@ -1091,7 +1079,7 @@
 		}
 
 		// initialize of not completely specified
-		if simplename(var_) || nodeSeqLen(n.List) < structcount(t) {
+		if simplename(var_) || n.List.Len() < structcount(t) {
 			a := Nod(OAS, var_, nil)
 			typecheck(&a, Etop)
 			walkexpr(&a, init)
@@ -1109,7 +1097,7 @@
 			break
 		}
 
-		if simplename(var_) && nodeSeqLen(n.List) > 4 {
+		if simplename(var_) && n.List.Len() > 4 {
 			if ctxt == 0 {
 				// lay out static data
 				vstat := staticname(t, ctxt)
@@ -1135,7 +1123,7 @@
 		}
 
 		// initialize of not completely specified
-		if simplename(var_) || int64(nodeSeqLen(n.List)) < t.Bound {
+		if simplename(var_) || int64(n.List.Len()) < t.Bound {
 			a := Nod(OAS, var_, nil)
 			typecheck(&a, Etop)
 			walkexpr(&a, init)
@@ -1257,8 +1245,7 @@
 		Fatalf("initplan")
 
 	case OARRAYLIT:
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			a := it.N()
+		for _, a := range n.List.Slice() {
 			if a.Op != OKEY || !Smallintconst(a.Left) {
 				Fatalf("initplan arraylit")
 			}
@@ -1266,8 +1253,7 @@
 		}
 
 	case OSTRUCTLIT:
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			a := it.N()
+		for _, a := range n.List.Slice() {
 			if a.Op != OKEY || a.Left.Type == nil {
 				Fatalf("initplan structlit")
 			}
@@ -1275,8 +1261,7 @@
 		}
 
 	case OMAPLIT:
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			a := it.N()
+		for _, a := range n.List.Slice() {
 			if a.Op != OKEY {
 				Fatalf("initplan maplit")
 			}
@@ -1351,8 +1336,8 @@
 
 		// fall through
 	case OSTRUCTLIT:
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if !iszero(it.N().Right) {
+		for _, n1 := range n.List.Slice() {
+			if !iszero(n1.Right) {
 				return false
 			}
 		}
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 8027a90..e124d02b 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -510,8 +510,8 @@
 
 // ssaStmtList converts the statement n to SSA and adds it to s.
 func (s *state) stmtList(l Nodes) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		s.stmt(it.N())
+	for _, n := range l.Slice() {
+		s.stmt(n)
 	}
 }
 
@@ -559,9 +559,9 @@
 		s.call(n.Left, callGo)
 
 	case OAS2DOTTYPE:
-		res, resok := s.dottype(nodeSeqFirst(n.Rlist), true)
-		s.assign(nodeSeqFirst(n.List), res, needwritebarrier(nodeSeqFirst(n.List), nodeSeqFirst(n.Rlist)), false, n.Lineno)
-		s.assign(nodeSeqSecond(n.List), resok, false, false, n.Lineno)
+		res, resok := s.dottype(n.Rlist.First(), true)
+		s.assign(n.List.First(), res, needwritebarrier(n.List.First(), n.Rlist.First()), false, n.Lineno)
+		s.assign(n.List.Second(), resok, false, false, n.Lineno)
 		return
 
 	case ODCL:
@@ -702,7 +702,7 @@
 		bThen := s.f.NewBlock(ssa.BlockPlain)
 		bEnd := s.f.NewBlock(ssa.BlockPlain)
 		var bElse *ssa.Block
-		if nodeSeqLen(n.Rlist) != 0 {
+		if n.Rlist.Len() != 0 {
 			bElse = s.f.NewBlock(ssa.BlockPlain)
 			s.condBranch(n.Left, bThen, bElse, n.Likely)
 		} else {
@@ -715,7 +715,7 @@
 			b.AddEdgeTo(bEnd)
 		}
 
-		if nodeSeqLen(n.Rlist) != 0 {
+		if n.Rlist.Len() != 0 {
 			s.startBlock(bElse)
 			s.stmtList(n.Rlist)
 			if b := s.endBlock(); b != nil {
@@ -2025,14 +2025,14 @@
 		pt := Ptrto(et)
 
 		// Evaluate slice
-		slice := s.expr(nodeSeqFirst(n.List))
+		slice := s.expr(n.List.First())
 
 		// Allocate new blocks
 		grow := s.f.NewBlock(ssa.BlockPlain)
 		assign := s.f.NewBlock(ssa.BlockPlain)
 
 		// Decide if we need to grow
-		nargs := int64(nodeSeqLen(n.List) - 1)
+		nargs := int64(n.List.Len() - 1)
 		p := s.newValue1(ssa.OpSlicePtr, pt, slice)
 		l := s.newValue1(ssa.OpSliceLen, Types[TINT], slice)
 		c := s.newValue1(ssa.OpSliceCap, Types[TINT], slice)
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 4d4be84..b264717 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -536,7 +536,7 @@
 		m.Orig = m
 		m.Left = treecopy(n.Left, lineno)
 		m.Right = treecopy(n.Right, lineno)
-		setNodeSeq(&m.List, listtreecopy(n.List.Slice(), lineno))
+		m.List.Set(listtreecopy(n.List.Slice(), lineno))
 		if lineno != 0 {
 			m.Lineno = lineno
 		}
@@ -1379,7 +1379,7 @@
 
 	var ul int
 	var ur int
-	if nodeSeqLen(n.Ninit) != 0 {
+	if n.Ninit.Len() != 0 {
 		ul = UINF
 		goto out
 	}
@@ -1497,7 +1497,7 @@
 		return nil
 	}
 
-	if nodeSeqLen(n.Ninit) != 0 {
+	if n.Ninit.Len() != 0 {
 		walkstmtlist(n.Ninit.Slice())
 		init.AppendNodes(&n.Ninit)
 	}
@@ -1968,8 +1968,8 @@
 		l = append(l, pad)
 	}
 
-	setNodeSeq(&t.List, append(l, in...))
-	setNodeSeq(&t.Rlist, out)
+	t.List.Set(append(l, in...))
+	t.Rlist.Set(out)
 
 	fn := Nod(ODCLFUNC, nil, nil)
 	fn.Func.Nname = newname(newnam)
@@ -2008,7 +2008,7 @@
 		v.U = method.Sym.Name
 		l = append(l, nodlit(v)) // method name
 		call := Nod(OCALL, syslook("panicwrap"), nil)
-		setNodeSeq(&call.List, l)
+		call.List.Set(l)
 		n.Nbody.Set([]*Node{call})
 		fn.Nbody.Append(n)
 	}
@@ -2031,11 +2031,11 @@
 	} else {
 		fn.Func.Wrapper = true // ignore frame for panic+recover matching
 		call := Nod(OCALL, dot, nil)
-		setNodeSeq(&call.List, args)
+		call.List.Set(args)
 		call.Isddd = isddd
 		if method.Type.Outtuple > 0 {
 			n := Nod(ORETURN, nil, nil)
-			setNodeSeq(&n.List, []*Node{call})
+			n.List.Set([]*Node{call})
 			call = n
 		}
 
@@ -2069,10 +2069,10 @@
 	n := newname(sym)
 	n.Class = PFUNC
 	tfn := Nod(OTFUNC, nil, nil)
-	appendNodeSeqNode(&tfn.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
-	appendNodeSeqNode(&tfn.List, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
-	appendNodeSeqNode(&tfn.List, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
-	appendNodeSeqNode(&tfn.Rlist, Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
+	tfn.List.Append(Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
+	tfn.List.Append(Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
+	tfn.List.Append(Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
+	tfn.Rlist.Append(Nod(ODCLFIELD, nil, typenod(Types[TUINTPTR])))
 	typecheck(&tfn, Etype)
 	n.Type = tfn.Type
 	return n
@@ -2218,15 +2218,15 @@
 
 func listtreecopy(l []*Node, lineno int32) []*Node {
 	var out []*Node
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		out = append(out, treecopy(it.N(), lineno))
+	for _, n := range l {
+		out = append(out, treecopy(n, lineno))
 	}
 	return out
 }
 
 func liststmt(l []*Node) *Node {
 	n := Nod(OBLOCK, nil, nil)
-	setNodeSeq(&n.List, l)
+	n.List.Set(l)
 	if nodeSeqLen(l) != 0 {
 		n.Lineno = nodeSeqFirst(l).Lineno
 	}
@@ -2573,7 +2573,7 @@
 		*np = n
 	}
 
-	setNodeSeq(&n.Ninit, append(nodeSeqSlice(init), nodeSeqSlice(n.Ninit)...))
+	n.Ninit.Set(append(nodeSeqSlice(init), n.Ninit.Slice()...))
 	n.Ullman = UINF
 }
 
diff --git a/src/cmd/compile/internal/gc/swt.go b/src/cmd/compile/internal/gc/swt.go
index 070f2ca..d54e4d6 100644
--- a/src/cmd/compile/internal/gc/swt.go
+++ b/src/cmd/compile/internal/gc/swt.go
@@ -105,10 +105,9 @@
 	n.Type = t
 
 	var def *Node
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		ncase := it.N()
+	for _, ncase := range n.List.Slice() {
 		setlineno(n)
-		if nodeSeqLen(ncase.List) == 0 {
+		if ncase.List.Len() == 0 {
 			// default
 			if def != nil {
 				Yyerror("multiple defaults in switch (first at %v)", def.Line())
@@ -116,30 +115,30 @@
 				def = ncase
 			}
 		} else {
-			for it2 := nodeSeqIterate(ncase.List); !it2.Done(); it2.Next() {
-				setlineno(it2.N())
-				typecheck(it2.P(), Erv|Etype)
-				if it2.N().Type == nil || t == nil {
+			for i1, n1 := range ncase.List.Slice() {
+				setlineno(n1)
+				typecheck(&ncase.List.Slice()[i1], Erv|Etype)
+				if ncase.List.Slice()[i1].Type == nil || t == nil {
 					continue
 				}
 				setlineno(ncase)
 				switch top {
 				// expression switch
 				case Erv:
-					defaultlit(it2.P(), t)
+					defaultlit(&ncase.List.Slice()[i1], t)
 					switch {
-					case it2.N().Op == OTYPE:
-						Yyerror("type %v is not an expression", it2.N().Type)
-					case it2.N().Type != nil && assignop(it2.N().Type, t, nil) == 0 && assignop(t, it2.N().Type, nil) == 0:
+					case ncase.List.Slice()[i1].Op == OTYPE:
+						Yyerror("type %v is not an expression", ncase.List.Slice()[i1].Type)
+					case ncase.List.Slice()[i1].Type != nil && assignop(ncase.List.Slice()[i1].Type, t, nil) == 0 && assignop(t, ncase.List.Slice()[i1].Type, nil) == 0:
 						if n.Left != nil {
-							Yyerror("invalid case %v in switch on %v (mismatched types %v and %v)", it2.N(), n.Left, it2.N().Type, t)
+							Yyerror("invalid case %v in switch on %v (mismatched types %v and %v)", ncase.List.Slice()[i1], n.Left, ncase.List.Slice()[i1].Type, t)
 						} else {
-							Yyerror("invalid case %v in switch (mismatched types %v and bool)", it2.N(), it2.N().Type)
+							Yyerror("invalid case %v in switch (mismatched types %v and bool)", ncase.List.Slice()[i1], ncase.List.Slice()[i1].Type)
 						}
-					case nilonly != "" && !isnil(it2.N()):
-						Yyerror("invalid case %v in switch (can only compare %s %v to nil)", it2.N(), nilonly, n.Left)
-					case Isinter(t) && !Isinter(it2.N().Type) && algtype1(it2.N().Type, nil) == ANOEQ:
-						Yyerror("invalid case %v in switch (incomparable type)", Nconv(it2.N(), obj.FmtLong))
+					case nilonly != "" && !isnil(ncase.List.Slice()[i1]):
+						Yyerror("invalid case %v in switch (can only compare %s %v to nil)", ncase.List.Slice()[i1], nilonly, n.Left)
+					case Isinter(t) && !Isinter(ncase.List.Slice()[i1].Type) && algtype1(ncase.List.Slice()[i1].Type, nil) == ANOEQ:
+						Yyerror("invalid case %v in switch (incomparable type)", Nconv(ncase.List.Slice()[i1], obj.FmtLong))
 					}
 
 				// type switch
@@ -147,16 +146,16 @@
 					var missing, have *Type
 					var ptr int
 					switch {
-					case it2.N().Op == OLITERAL && Istype(it2.N().Type, TNIL):
-					case it2.N().Op != OTYPE && it2.N().Type != nil: // should this be ||?
-						Yyerror("%v is not a type", Nconv(it2.N(), obj.FmtLong))
+					case ncase.List.Slice()[i1].Op == OLITERAL && Istype(ncase.List.Slice()[i1].Type, TNIL):
+					case ncase.List.Slice()[i1].Op != OTYPE && ncase.List.Slice()[i1].Type != nil: // should this be ||?
+						Yyerror("%v is not a type", Nconv(ncase.List.Slice()[i1], obj.FmtLong))
 						// reset to original type
-						*it2.P() = n.Left.Right
-					case it2.N().Type.Etype != TINTER && t.Etype == TINTER && !implements(it2.N().Type, t, &missing, &have, &ptr):
+						ncase.List.Slice()[i1] = n.Left.Right
+					case ncase.List.Slice()[i1].Type.Etype != TINTER && t.Etype == TINTER && !implements(ncase.List.Slice()[i1].Type, t, &missing, &have, &ptr):
 						if have != nil && !missing.Broke && !have.Broke {
-							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (wrong type for %v method)\n\thave %v%v\n\twant %v%v", Nconv(n.Left.Right, obj.FmtLong), it2.N().Type, missing.Sym, have.Sym, Tconv(have.Type, obj.FmtShort), missing.Sym, Tconv(missing.Type, obj.FmtShort))
+							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (wrong type for %v method)\n\thave %v%v\n\twant %v%v", Nconv(n.Left.Right, obj.FmtLong), ncase.List.Slice()[i1].Type, missing.Sym, have.Sym, Tconv(have.Type, obj.FmtShort), missing.Sym, Tconv(missing.Type, obj.FmtShort))
 						} else if !missing.Broke {
-							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (missing %v method)", Nconv(n.Left.Right, obj.FmtLong), it2.N().Type, missing.Sym)
+							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (missing %v method)", Nconv(n.Left.Right, obj.FmtLong), ncase.List.Slice()[i1].Type, missing.Sym)
 						}
 					}
 				}
@@ -165,11 +164,11 @@
 
 		if top == Etype && n.Type != nil {
 			ll := ncase.List
-			if nodeSeqLen(ncase.Rlist) != 0 {
-				nvar := nodeSeqFirst(ncase.Rlist)
-				if nodeSeqLen(ll) == 1 && nodeSeqFirst(ll).Type != nil && !Istype(nodeSeqFirst(ll).Type, TNIL) {
+			if ncase.Rlist.Len() != 0 {
+				nvar := ncase.Rlist.First()
+				if ll.Len() == 1 && ll.First().Type != nil && !Istype(ll.First().Type, TNIL) {
 					// single entry type switch
-					nvar.Name.Param.Ntype = typenod(nodeSeqFirst(ll).Type)
+					nvar.Name.Param.Ntype = typenod(ll.First().Type)
 				} else {
 					// multiple entry type switch or default
 					nvar.Name.Param.Ntype = typenod(n.Type)
@@ -244,7 +243,7 @@
 
 	// enumerate the cases, and lop off the default case
 	cc := caseClauses(sw, s.kind)
-	setNodeSeq(&sw.List, nil)
+	sw.List.Set(nil)
 	var def *Node
 	if len(cc) > 0 && cc[0].typ == caseKindDefault {
 		def = cc[0].node.Right
@@ -326,7 +325,7 @@
 	}
 	typecheck(&a.Left, Erv)
 	a.Nbody.Set([]*Node{s.walkCases(cc[:half])})
-	setNodeSeq(&a.Rlist, []*Node{s.walkCases(cc[half:])})
+	a.Rlist.Set([]*Node{s.walkCases(cc[half:])})
 	return a
 }
 
@@ -334,7 +333,7 @@
 // It makes labels between cases and statements
 // and deals with fallthrough, break, and unreachable statements.
 func casebody(sw *Node, typeswvar *Node) {
-	if nodeSeqLen(sw.List) == 0 {
+	if sw.List.Len() == 0 {
 		return
 	}
 
@@ -352,10 +351,10 @@
 			Fatalf("casebody %v", Oconv(n.Op, 0))
 		}
 		n.Op = OCASE
-		needvar := nodeSeqLen(n.List) != 1 || nodeSeqFirst(n.List).Op == OLITERAL
+		needvar := n.List.Len() != 1 || n.List.First().Op == OLITERAL
 
 		jmp := Nod(OGOTO, newCaseLabel(), nil)
-		if nodeSeqLen(n.List) == 0 {
+		if n.List.Len() == 0 {
 			if def != nil {
 				Yyerror("more than one default case")
 			}
@@ -364,24 +363,24 @@
 			def = n
 		}
 
-		if nodeSeqLen(n.List) == 1 {
+		if n.List.Len() == 1 {
 			// one case -- reuse OCASE node
-			n.Left = nodeSeqFirst(n.List)
+			n.Left = n.List.First()
 			n.Right = jmp
-			setNodeSeq(&n.List, nil)
+			n.List.Set(nil)
 			cas = append(cas, n)
 		} else {
 			// expand multi-valued cases
-			for lcit := nodeSeqIterate(n.List); !lcit.Done(); lcit.Next() {
-				cas = append(cas, Nod(OCASE, lcit.N(), jmp))
+			for _, n1 := range n.List.Slice() {
+				cas = append(cas, Nod(OCASE, n1, jmp))
 			}
 		}
 
 		stat = append(stat, Nod(OLABEL, jmp.Left, nil))
-		if typeswvar != nil && needvar && nodeSeqLen(n.Rlist) != 0 {
+		if typeswvar != nil && needvar && n.Rlist.Len() != 0 {
 			l := []*Node{
-				Nod(ODCL, nodeSeqFirst(n.Rlist), nil),
-				Nod(OAS, nodeSeqFirst(n.Rlist), typeswvar),
+				Nod(ODCL, n.Rlist.First(), nil),
+				Nod(OAS, n.Rlist.First(), typeswvar),
 			}
 			typecheckslice(l, Etop)
 			stat = append(stat, l...)
@@ -412,7 +411,7 @@
 		cas = append(cas, def)
 	}
 
-	setNodeSeq(&sw.List, cas)
+	sw.List.Set(cas)
 	sw.Nbody.Set(stat)
 	lineno = lno
 }
@@ -432,8 +431,7 @@
 // Kind is the kind of switch statement.
 func caseClauses(sw *Node, kind int) []*caseClause {
 	var cc []*caseClause
-	for it := nodeSeqIterate(sw.List); !it.Done(); it.Next() {
-		n := it.N()
+	for _, n := range sw.List.Slice() {
 		c := new(caseClause)
 		cc = append(cc, c)
 		c.ordinal = len(cc)
@@ -518,7 +516,7 @@
 	sw.Left = nil
 
 	if cond == nil {
-		setNodeSeq(&sw.List, nil)
+		sw.List.Set(nil)
 		return
 	}
 	if cond.Right == nil {
@@ -552,7 +550,7 @@
 	casebody(sw, s.facename)
 
 	cc := caseClauses(sw, switchKindType)
-	setNodeSeq(&sw.List, nil)
+	sw.List.Set(nil)
 	var def *Node
 	if len(cc) > 0 && cc[0].typ == caseKindDefault {
 		def = cc[0].node.Right
@@ -588,7 +586,7 @@
 		i.Nbody.Set([]*Node{Nod(OGOTO, lbl, nil)})
 		// Wrap default case with label.
 		blk := Nod(OBLOCK, nil, nil)
-		setNodeSeq(&blk.List, []*Node{Nod(OLABEL, lbl, nil), def})
+		blk.List.Set([]*Node{Nod(OLABEL, lbl, nil), def})
 		def = blk
 	}
 	typecheck(&i.Left, Erv)
@@ -669,7 +667,7 @@
 	if nerrors == 0 {
 		cas = append(cas, def)
 		sw.Nbody.Set(append(cas, sw.Nbody.Slice()...))
-		setNodeSeq(&sw.List, nil)
+		sw.List.Set(nil)
 		walkstmtlist(sw.Nbody.Slice())
 	}
 }
@@ -679,11 +677,11 @@
 func (s *typeSwitch) typeone(t *Node) *Node {
 	var name *Node
 	var init []*Node
-	if nodeSeqLen(t.Rlist) == 0 {
+	if t.Rlist.Len() == 0 {
 		name = nblank
 		typecheck(&nblank, Erv|Easgn)
 	} else {
-		name = nodeSeqFirst(t.Rlist)
+		name = t.Rlist.First()
 		init = []*Node{Nod(ODCL, name, nil)}
 		a := Nod(OAS, name, nil)
 		typecheck(&a, Etop)
@@ -691,10 +689,10 @@
 	}
 
 	a := Nod(OAS2, nil, nil)
-	setNodeSeq(&a.List, []*Node{name, s.okname}) // name, ok =
+	a.List.Set([]*Node{name, s.okname}) // name, ok =
 	b := Nod(ODOTTYPE, s.facename, nil)
 	b.Type = t.Left.Type // interface.(type)
-	setNodeSeq(&a.Rlist, []*Node{b})
+	a.Rlist.Set([]*Node{b})
 	typecheck(&a, Etop)
 	init = append(init, a)
 
@@ -729,7 +727,7 @@
 	a.Left = Nod(OLE, s.hashname, Nodintconst(int64(cc[half-1].hash)))
 	typecheck(&a.Left, Erv)
 	a.Nbody.Set([]*Node{s.walkCases(cc[:half])})
-	setNodeSeq(&a.Rlist, []*Node{s.walkCases(cc[half:])})
+	a.Rlist.Set([]*Node{s.walkCases(cc[half:])})
 	return a
 }
 
diff --git a/src/cmd/compile/internal/gc/syntax.go b/src/cmd/compile/internal/gc/syntax.go
index 6ac1f29..59748ea 100644
--- a/src/cmd/compile/internal/gc/syntax.go
+++ b/src/cmd/compile/internal/gc/syntax.go
@@ -429,6 +429,26 @@
 	return *n.slice
 }
 
+// Len returns the number of entries in Nodes.
+func (n *Nodes) Len() int {
+	if n.slice == nil {
+		return 0
+	}
+	return len(*n.slice)
+}
+
+// First returns the first element of Nodes.
+// It panics if Nodes has no elements.
+func (n *Nodes) First() *Node {
+	return (*n.slice)[0]
+}
+
+// Second returns the second element of Nodes.
+// It panics if Nodes has fewer than two elements.
+func (n *Nodes) Second() *Node {
+	return (*n.slice)[1]
+}
+
 // NodeList returns the entries in Nodes as a NodeList.
 // Changes to the NodeList entries (as in l.N = n) will *not* be
 // reflected in the Nodes.
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 85605dc..e1840ee 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -35,8 +35,8 @@
 }
 
 func typechecklist(l []*Node, top int) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		typecheck(it.P(), top)
+	for i := range l {
+		typecheck(&l[i], top)
 	}
 }
 
@@ -221,8 +221,8 @@
 }
 
 func callrecvlist(l Nodes) bool {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		if callrecv(it.N()) {
+	for _, n := range l.Slice() {
+		if callrecv(n) {
 			return true
 		}
 	}
@@ -431,7 +431,7 @@
 			n.Type = nil
 			return
 		}
-		setNodeSeq(&n.List, nil)
+		n.List.Set(nil)
 
 	case OTINTER:
 		ok |= Etype
@@ -704,14 +704,14 @@
 				n.Op = OADDSTR
 
 				if l.Op == OADDSTR {
-					setNodeSeq(&n.List, l.List)
+					n.List.Set(l.List.Slice())
 				} else {
-					setNodeSeq(&n.List, []*Node{l})
+					n.List.Set([]*Node{l})
 				}
 				if r.Op == OADDSTR {
-					appendNodeSeq(&n.List, r.List)
+					n.List.AppendNodes(&r.List)
 				} else {
-					appendNodeSeqNode(&n.List, r)
+					n.List.Append(r)
 				}
 				n.Left = nil
 				n.Right = nil
@@ -1288,7 +1288,7 @@
 			return
 		}
 
-		if nodeSeqLen(n.List) == 1 && !n.Isddd {
+		if n.List.Len() == 1 && !n.Isddd {
 			it := nodeSeqIterate(n.List)
 			typecheck(it.P(), Erv|Efnstruct)
 		} else {
@@ -1446,22 +1446,22 @@
 		ok |= Erv
 		var r *Node
 		var l *Node
-		if nodeSeqLen(n.List) == 1 {
+		if n.List.Len() == 1 {
 			typechecklist(n.List.Slice(), Efnstruct)
-			if nodeSeqFirst(n.List).Op != OCALLFUNC && nodeSeqFirst(n.List).Op != OCALLMETH {
+			if n.List.First().Op != OCALLFUNC && n.List.First().Op != OCALLMETH {
 				Yyerror("invalid operation: complex expects two arguments")
 				n.Type = nil
 				return
 			}
 
-			t := nodeSeqFirst(n.List).Left.Type
+			t := n.List.First().Left.Type
 			if t.Outtuple != 2 {
-				Yyerror("invalid operation: complex expects two arguments, %v returns %d results", nodeSeqFirst(n.List), t.Outtuple)
+				Yyerror("invalid operation: complex expects two arguments, %v returns %d results", n.List.First(), t.Outtuple)
 				n.Type = nil
 				return
 			}
 
-			t = nodeSeqFirst(n.List).Type.Type
+			t = n.List.First().Type.Type
 			l = t.Nname
 			r = t.Down.Nname
 		} else {
@@ -1548,19 +1548,19 @@
 
 	case ODELETE:
 		args := n.List
-		if nodeSeqLen(args) == 0 {
+		if args.Len() == 0 {
 			Yyerror("missing arguments to delete")
 			n.Type = nil
 			return
 		}
 
-		if nodeSeqLen(args) == 1 {
+		if args.Len() == 1 {
 			Yyerror("missing second (key) argument to delete")
 			n.Type = nil
 			return
 		}
 
-		if nodeSeqLen(args) != 2 {
+		if args.Len() != 2 {
 			Yyerror("too many arguments to delete")
 			n.Type = nil
 			return
@@ -1568,8 +1568,8 @@
 
 		ok |= Etop
 		typechecklist(args.Slice(), Erv)
-		l := nodeSeqFirst(args)
-		r := nodeSeqSecond(args)
+		l := args.First()
+		r := args.Second()
 		if l.Type != nil && l.Type.Etype != TMAP {
 			Yyerror("first argument to delete must be map; have %v", Tconv(l.Type, obj.FmtLong))
 			n.Type = nil
@@ -1584,20 +1584,20 @@
 	case OAPPEND:
 		ok |= Erv
 		args := n.List
-		if nodeSeqLen(args) == 0 {
+		if args.Len() == 0 {
 			Yyerror("missing arguments to append")
 			n.Type = nil
 			return
 		}
 
-		if nodeSeqLen(args) == 1 && !n.Isddd {
+		if args.Len() == 1 && !n.Isddd {
 			it := nodeSeqIterate(args)
 			typecheck(it.P(), Erv|Efnstruct)
 		} else {
 			typechecklist(args.Slice(), Erv)
 		}
 
-		t := nodeSeqFirst(args).Type
+		t := args.First().Type
 		if t == nil {
 			n.Type = nil
 			return
@@ -1612,7 +1612,7 @@
 
 		n.Type = t
 		if !Isslice(t) {
-			if Isconst(nodeSeqFirst(args), CTNIL) {
+			if Isconst(args.First(), CTNIL) {
 				Yyerror("first argument to append must be typed slice; have untyped nil")
 				n.Type = nil
 				return
@@ -1624,19 +1624,19 @@
 		}
 
 		if n.Isddd {
-			if nodeSeqLen(args) == 1 {
+			if args.Len() == 1 {
 				Yyerror("cannot use ... on first argument to append")
 				n.Type = nil
 				return
 			}
 
-			if nodeSeqLen(args) != 2 {
+			if args.Len() != 2 {
 				Yyerror("too many arguments to append")
 				n.Type = nil
 				return
 			}
 
-			if Istype(t.Type, TUINT8) && Istype(nodeSeqSecond(args).Type, TSTRING) {
+			if Istype(t.Type, TUINT8) && Istype(args.Second().Type, TSTRING) {
 				it := nodeSeqIterate(args)
 				it.Next()
 				defaultlit(it.P(), Types[TSTRING])
@@ -1645,7 +1645,7 @@
 
 			it := nodeSeqIterate(args)
 			it.Next()
-			*it.P() = assignconv(nodeSeqSecond(args), t.Orig, "append")
+			*it.P() = assignconv(args.Second(), t.Orig, "append")
 			break OpSwitch
 		}
 
@@ -1671,21 +1671,21 @@
 	case OCOPY:
 		ok |= Etop | Erv
 		args := n.List
-		if nodeSeqLen(args) < 2 {
+		if args.Len() < 2 {
 			Yyerror("missing arguments to copy")
 			n.Type = nil
 			return
 		}
 
-		if nodeSeqLen(args) > 2 {
+		if args.Len() > 2 {
 			Yyerror("too many arguments to copy")
 			n.Type = nil
 			return
 		}
 
-		n.Left = nodeSeqFirst(args)
-		n.Right = nodeSeqSecond(args)
-		setNodeSeq(&n.List, nil)
+		n.Left = args.First()
+		n.Right = args.Second()
+		n.List.Set(nil)
 		n.Type = Types[TINT]
 		typecheck(&n.Left, Erv)
 		typecheck(&n.Right, Erv)
@@ -1784,7 +1784,7 @@
 			return
 		}
 
-		setNodeSeq(&n.List, nil)
+		n.List.Set(nil)
 		l := args.N()
 		args.Next()
 		typecheck(&l, Etype)
@@ -1896,20 +1896,20 @@
 	case ONEW:
 		ok |= Erv
 		args := n.List
-		if nodeSeqLen(args) == 0 {
+		if args.Len() == 0 {
 			Yyerror("missing argument to new")
 			n.Type = nil
 			return
 		}
 
-		l := nodeSeqFirst(args)
+		l := args.First()
 		typecheck(&l, Etype)
 		t := l.Type
 		if t == nil {
 			n.Type = nil
 			return
 		}
-		if nodeSeqLen(args) > 1 {
+		if args.Len() > 1 {
 			Yyerror("too many arguments to new(%v)", t)
 			n.Type = nil
 			return
@@ -1922,12 +1922,12 @@
 	case OPRINT, OPRINTN:
 		ok |= Etop
 		typechecklist(n.List.Slice(), Erv|Eindir) // Eindir: address does not escape
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
+		for i1, n1 := range n.List.Slice() {
 			// Special case for print: int constant is int64, not int.
-			if Isconst(it.N(), CTINT) {
-				defaultlit(it.P(), Types[TINT64])
+			if Isconst(n1, CTINT) {
+				defaultlit(&n.List.Slice()[i1], Types[TINT64])
 			} else {
-				defaultlit(it.P(), nil)
+				defaultlit(&n.List.Slice()[i1], nil)
 			}
 		}
 
@@ -1949,7 +1949,7 @@
 
 	case ORECOVER:
 		ok |= Erv | Etop
-		if nodeSeqLen(n.List) != 0 {
+		if n.List.Len() != 0 {
 			Yyerror("too many arguments to recover")
 			n.Type = nil
 			return
@@ -2093,7 +2093,7 @@
 
 	case ORETURN:
 		ok |= Etop
-		if nodeSeqLen(n.List) == 1 {
+		if n.List.Len() == 1 {
 			typechecklist(n.List.Slice(), Erv|Efnstruct)
 		} else {
 			typechecklist(n.List.Slice(), Erv)
@@ -2104,7 +2104,7 @@
 			return
 		}
 
-		if Curfn.Type.Outnamed && nodeSeqLen(n.List) == 0 {
+		if Curfn.Type.Outnamed && n.List.Len() == 0 {
 			break OpSwitch
 		}
 		typecheckaste(ORETURN, nil, false, Curfn.Type.Results(), n.List, func() string { return "return argument" })
@@ -2332,22 +2332,22 @@
 	if n.Left != nil {
 		return true
 	}
-	if nodeSeqLen(n.List) == 0 {
+	if n.List.Len() == 0 {
 		p := fmt.Sprintf(f, args...)
 		Yyerror("missing argument to %s: %v", p, n)
 		return false
 	}
 
-	if nodeSeqLen(n.List) > 1 {
+	if n.List.Len() > 1 {
 		p := fmt.Sprintf(f, args...)
 		Yyerror("too many arguments to %s: %v", p, n)
-		n.Left = nodeSeqFirst(n.List)
-		setNodeSeq(&n.List, nil)
+		n.Left = n.List.First()
+		n.List.Set(nil)
 		return false
 	}
 
-	n.Left = nodeSeqFirst(n.List)
-	setNodeSeq(&n.List, nil)
+	n.Left = n.List.First()
+	n.List.Set(nil)
 	return true
 }
 
@@ -2355,26 +2355,26 @@
 	if n.Left != nil {
 		return true
 	}
-	if nodeSeqLen(n.List) == 0 {
+	if n.List.Len() == 0 {
 		Yyerror("missing argument to %v - %v", Oconv(n.Op, 0), n)
 		return false
 	}
 
-	n.Left = nodeSeqFirst(n.List)
-	if nodeSeqLen(n.List) == 1 {
+	n.Left = n.List.First()
+	if n.List.Len() == 1 {
 		Yyerror("missing argument to %v - %v", Oconv(n.Op, 0), n)
-		setNodeSeq(&n.List, nil)
+		n.List.Set(nil)
 		return false
 	}
 
-	if nodeSeqLen(n.List) > 2 {
+	if n.List.Len() > 2 {
 		Yyerror("too many arguments to %v - %v", Oconv(n.Op, 0), n)
-		setNodeSeq(&n.List, nil)
+		n.List.Set(nil)
 		return false
 	}
 
-	n.Right = nodeSeqSecond(n.List)
-	setNodeSeq(&n.List, nil)
+	n.Right = n.List.Second()
+	n.List.Set(nil)
 	return true
 }
 
@@ -2576,8 +2576,8 @@
 }
 
 func nokeys(l Nodes) bool {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		if it.N().Op == OKEY {
+	for _, n := range l.Slice() {
+		if n.Op == OKEY {
 			return false
 		}
 	}
@@ -2620,8 +2620,8 @@
 	}
 
 	n = nil
-	if nodeSeqLen(nl) == 1 {
-		n = nodeSeqFirst(nl)
+	if nl.Len() == 1 {
+		n = nl.First()
 		if n.Type != nil {
 			if n.Type.Etype == TSTRUCT && n.Type.Funarg {
 				if !hasddd(tstruct) {
@@ -2675,7 +2675,7 @@
 	}
 
 	n1 = downcount(tstruct)
-	n2 = nodeSeqLen(nl)
+	n2 = nl.Len()
 	if !hasddd(tstruct) {
 		if n2 > n1 {
 			goto toomany
@@ -2917,8 +2917,8 @@
 	}()
 
 	if n.Right == nil {
-		if nodeSeqLen(n.List) != 0 {
-			setlineno(nodeSeqFirst(n.List))
+		if n.List.Len() != 0 {
+			setlineno(n.List.First())
 		}
 		Yyerror("missing type in composite literal")
 		n.Type = nil
@@ -2968,22 +2968,22 @@
 	case TARRAY:
 		// Only allocate hash if there are some key/value pairs.
 		var hash map[int64]*Node
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if it.N().Op == OKEY {
+		for _, n1 := range n.List.Slice() {
+			if n1.Op == OKEY {
 				hash = make(map[int64]*Node)
 				break
 			}
 		}
 		length := int64(0)
 		i := 0
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			l := it.N()
+		for i2, n2 := range n.List.Slice() {
+			l := n2
 			setlineno(l)
 			if l.Op != OKEY {
 				l = Nod(OKEY, Nodintconst(int64(i)), l)
 				l.Left.Type = Types[TINT]
 				l.Left.Typecheck = 1
-				*it.P() = l
+				n.List.Slice()[i2] = l
 			}
 
 			typecheck(&l.Left, Erv)
@@ -3026,11 +3026,11 @@
 	case TMAP:
 		hash := make(map[uint32][]*Node)
 		var l *Node
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			l = it.N()
+		for i3, n3 := range n.List.Slice() {
+			l = n3
 			setlineno(l)
 			if l.Op != OKEY {
-				typecheck(it.P(), Erv)
+				typecheck(&n.List.Slice()[i3], Erv)
 				Yyerror("missing key in map literal")
 				continue
 			}
@@ -3055,14 +3055,14 @@
 
 	case TSTRUCT:
 		bad := 0
-		if nodeSeqLen(n.List) != 0 && nokeys(n.List) {
+		if n.List.Len() != 0 && nokeys(n.List) {
 			// simple list of variables
 			f := t.Type
 
 			var s *Sym
-			for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-				setlineno(it.N())
-				typecheck(it.P(), Erv)
+			for i4, n4 := range n.List.Slice() {
+				setlineno(n4)
+				typecheck(&n.List.Slice()[i4], Erv)
 				if f == nil {
 					if bad == 0 {
 						Yyerror("too many values in struct initializer")
@@ -3075,13 +3075,11 @@
 				if s != nil && !exportname(s.Name) && s.Pkg != localpkg {
 					Yyerror("implicit assignment of unexported field '%s' in %v literal", s.Name, t)
 				}
-
 				// No pushtype allowed here. Must name fields for that.
-				*it.P() = assignconv(it.N(), f.Type, "field value")
-
-				*it.P() = Nod(OKEY, newname(f.Sym), it.N())
-				it.N().Left.Type = f
-				it.N().Left.Typecheck = 1
+				n.List.Slice()[i4] = assignconv(n.List.Slice()[i4], f.Type, "field value")
+				n.List.Slice()[i4] = Nod(OKEY, newname(f.Sym), n.List.Slice()[i4])
+				n.List.Slice()[i4].Left.Type = f
+				n.List.Slice()[i4].Left.Typecheck = 1
 				f = f.Down
 			}
 
@@ -3096,15 +3094,15 @@
 			var f *Type
 			var l *Node
 			var s1 *Sym
-			for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-				l = it.N()
+			for i5, n5 := range n.List.Slice() {
+				l = n5
 				setlineno(l)
 				if l.Op != OKEY {
 					if bad == 0 {
 						Yyerror("mixture of field:value and value initializers")
 					}
 					bad++
-					typecheck(it.P(), Erv)
+					typecheck(&n.List.Slice()[i5], Erv)
 					continue
 				}
 
@@ -3236,8 +3234,8 @@
 }
 
 func checkassignlist(stmt *Node, l Nodes) {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		checkassign(stmt, it.N())
+	for _, n := range l.Slice() {
+		checkassign(stmt, n)
 	}
 }
 
@@ -3315,17 +3313,17 @@
 }
 
 func typecheckas2(n *Node) {
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
+	for i1 := range n.List.Slice() {
 		// delicate little dance.
-		*it.P() = resolve(it.N())
+		n.List.Slice()[i1] = resolve(n.List.Slice()[i1])
 
-		if it.N().Name == nil || it.N().Name.Defn != n || it.N().Name.Param.Ntype != nil {
-			typecheck(it.P(), Erv|Easgn)
+		if n.List.Slice()[i1].Name == nil || n.List.Slice()[i1].Name.Defn != n || n.List.Slice()[i1].Name.Param.Ntype != nil {
+			typecheck(&n.List.Slice()[i1], Erv|Easgn)
 		}
 	}
 
-	cl := nodeSeqLen(n.List)
-	cr := nodeSeqLen(n.Rlist)
+	cl := n.List.Len()
+	cr := n.Rlist.Len()
 	if cl > 1 && cr == 1 {
 		it := nodeSeqIterate(n.Rlist)
 		typecheck(it.P(), Erv|Efnstruct)
@@ -3339,13 +3337,13 @@
 	if cl == cr {
 		// easy
 		lrit := nodeSeqIterate(n.Rlist)
-		for llit := nodeSeqIterate(n.List); !llit.Done(); llit.Next() {
-			if llit.N().Type != nil && lrit.N().Type != nil {
-				*lrit.P() = assignconv(lrit.N(), llit.N().Type, "assignment")
+		for _, n2 := range n.List.Slice() {
+			if n2.Type != nil && lrit.N().Type != nil {
+				*lrit.P() = assignconv(lrit.N(), n2.Type, "assignment")
 			}
-			if llit.N().Name != nil && llit.N().Name.Defn == n && llit.N().Name.Param.Ntype == nil {
+			if n2.Name != nil && n2.Name.Defn == n && n2.Name.Param.Ntype == nil {
 				defaultlit(lrit.P(), nil)
-				llit.N().Type = lrit.N().Type
+				n2.Type = lrit.N().Type
 			}
 			lrit.Next()
 		}
@@ -3353,8 +3351,8 @@
 		goto out
 	}
 
-	l = nodeSeqFirst(n.List)
-	r = nodeSeqFirst(n.Rlist)
+	l = n.List.First()
+	r = n.Rlist.First()
 
 	// x,y,z = f()
 	if cr == 1 {
@@ -3372,12 +3370,12 @@
 			}
 			n.Op = OAS2FUNC
 			t, s := IterFields(r.Type)
-			for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-				if t.Type != nil && it.N().Type != nil {
-					checkassignto(t.Type, it.N())
+			for _, n3 := range n.List.Slice() {
+				if t.Type != nil && n3.Type != nil {
+					checkassignto(t.Type, n3)
 				}
-				if it.N().Name != nil && it.N().Name.Defn == n && it.N().Name.Param.Ntype == nil {
-					it.N().Type = t.Type
+				if n3.Name != nil && n3.Name.Defn == n && n3.Name.Param.Ntype == nil {
+					n3.Type = t.Type
 				}
 				t = s.Next()
 			}
@@ -3411,7 +3409,7 @@
 			if l.Name != nil && l.Name.Defn == n {
 				l.Type = r.Type
 			}
-			l := nodeSeqSecond(n.List)
+			l := n.List.Second()
 			if l.Type != nil && l.Type.Etype != TBOOL {
 				checkassignto(Types[TBOOL], l)
 			}
@@ -3428,10 +3426,9 @@
 	// second half of dance
 out:
 	n.Typecheck = 1
-
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		if it.N().Typecheck == 0 {
-			typecheck(it.P(), Erv|Easgn)
+	for i4, n4 := range n.List.Slice() {
+		if n4.Typecheck == 0 {
+			typecheck(&n.List.Slice()[i4], Erv|Easgn)
 		}
 	}
 }
@@ -3480,7 +3477,7 @@
 	}
 
 	nn := Nod(OCOMPLIT, nil, typenod(n.Type))
-	setNodeSeq(&nn.List, l)
+	nn.List.Set(l)
 	typecheck(&nn, Erv)
 	*np = nn
 }
@@ -3966,11 +3963,11 @@
 			return false
 		}
 		def := 0
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if !it.N().Nbody.isterminating() {
+		for _, n1 := range n.List.Slice() {
+			if !n1.Nbody.isterminating() {
 				return false
 			}
-			if nodeSeqLen(it.N().List) == 0 { // default
+			if n1.List.Len() == 0 { // default
 				def = 1
 			}
 		}
diff --git a/src/cmd/compile/internal/gc/unsafe.go b/src/cmd/compile/internal/gc/unsafe.go
index 9bfc6a5..99e0ac8 100644
--- a/src/cmd/compile/internal/gc/unsafe.go
+++ b/src/cmd/compile/internal/gc/unsafe.go
@@ -26,12 +26,12 @@
 		return nil
 	}
 
-	if nodeSeqLen(args) == 0 {
+	if args.Len() == 0 {
 		Yyerror("missing argument for %v", s)
 		return nil
 	}
 
-	r := nodeSeqFirst(args)
+	r := args.First()
 
 	var v int64
 	if s.Name == "Sizeof" {
@@ -129,7 +129,7 @@
 	goto ret
 
 yes:
-	if nodeSeqLen(args) > 1 {
+	if args.Len() > 1 {
 		Yyerror("extra arguments for %v", s)
 	}
 
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 1db951c..a53d1bd 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -119,8 +119,7 @@
 	var lhs *Node
 
 	callfunc := n.Left
-	for argsit := nodeSeqIterate(callfunc.List); !argsit.Done(); argsit.Next() {
-		arg = argsit.N()
+	for _, arg = range callfunc.List.Slice() {
 		if arg.Op != OAS {
 			Yyerror("call arg not assignment")
 		}
@@ -189,7 +188,7 @@
 			Fatalf("missing typecheck: %v", Nconv(n, obj.FmtSign))
 		}
 		init := n.Ninit
-		setNodeSeq(&n.Ninit, nil)
+		n.Ninit.Set(nil)
 		walkexpr(&n, &init)
 		addinit(&n, init.Slice())
 		if (*np).Op == OCOPY && n.Op == OCONVNOP {
@@ -203,7 +202,7 @@
 			Fatalf("missing typecheck: %v", Nconv(n, obj.FmtSign))
 		}
 		init := n.Ninit
-		setNodeSeq(&n.Ninit, nil)
+		n.Ninit.Set(nil)
 
 		walkexpr(&n.Left, &init)
 		n = mkcall1(chanfn("chanrecv1", 2, n.Left.Type), nil, &init, typename(n.Left.Type), n.Left, nodnil())
@@ -255,7 +254,7 @@
 		if n.Left != nil {
 			walkstmtlist(n.Left.Ninit.Slice())
 			init := n.Left.Ninit
-			setNodeSeq(&n.Left.Ninit, nil)
+			n.Left.Ninit.Set(nil)
 			walkexpr(&n.Left, &init)
 			addinit(&n.Left, init.Slice())
 		}
@@ -285,10 +284,10 @@
 
 	case ORETURN:
 		walkexprlist(n.List.Slice(), &n.Ninit)
-		if nodeSeqLen(n.List) == 0 {
+		if n.List.Len() == 0 {
 			break
 		}
-		if (Curfn.Type.Outnamed && nodeSeqLen(n.List) > 1) || paramoutheap(Curfn) {
+		if (Curfn.Type.Outnamed && n.List.Len() > 1) || paramoutheap(Curfn) {
 			// assign to the function out parameters,
 			// so that reorder3 can fix up conflicts
 			var rl []*Node
@@ -304,7 +303,7 @@
 				}
 			}
 
-			if got, want := nodeSeqLen(n.List), len(rl); got != want {
+			if got, want := n.List.Len(), len(rl); got != want {
 				// order should have rewritten multi-value function calls
 				// with explicit OAS2FUNC nodes.
 				Fatalf("expected %v return arguments, have %v", want, got)
@@ -312,7 +311,7 @@
 
 			if samelist(rl, n.List.Slice()) {
 				// special return in disguise
-				setNodeSeq(&n.List, nil)
+				n.List.Set(nil)
 
 				break
 			}
@@ -321,15 +320,15 @@
 			walkexprlistsafe(n.List.Slice(), &n.Ninit)
 
 			ll := ascompatee(n.Op, rl, n.List.Slice(), &n.Ninit)
-			setNodeSeq(&n.List, reorder3(ll))
-			for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-				*it.P() = applywritebarrier(it.N())
+			n.List.Set(reorder3(ll))
+			for i1 := range n.List.Slice() {
+				n.List.Slice()[i1] = applywritebarrier(n.List.Slice()[i1])
 			}
 			break
 		}
 
 		ll := ascompatte(n.Op, nil, false, Curfn.Type.ResultsP(), n.List.Slice(), 1, &n.Ninit)
-		setNodeSeq(&n.List, ll)
+		n.List.Set(ll)
 
 	case ORETJMP:
 		break
@@ -465,7 +464,7 @@
 		Fatalf("walkexpr init == &n->ninit")
 	}
 
-	if nodeSeqLen(n.Ninit) != 0 {
+	if n.Ninit.Len() != 0 {
 		walkstmtlist(n.Ninit.Slice())
 		init.AppendNodes(&n.Ninit)
 	}
@@ -572,8 +571,8 @@
 		OCOMPLEX,
 		OLROT:
 		if n.Op == OCOMPLEX && n.Left == nil && n.Right == nil {
-			n.Left = nodeSeqFirst(n.List)
-			n.Right = nodeSeqSecond(n.List)
+			n.Left = n.List.First()
+			n.Right = n.List.Second()
 		}
 
 		walkexpr(&n.Left, init)
@@ -633,13 +632,13 @@
 
 	case OCALLINTER:
 		t := n.Left.Type
-		if nodeSeqLen(n.List) != 0 && nodeSeqFirst(n.List).Op == OAS {
+		if n.List.Len() != 0 && n.List.First().Op == OAS {
 			break
 		}
 		walkexpr(&n.Left, init)
 		walkexprlist(n.List.Slice(), init)
 		ll := ascompatte(n.Op, n, n.Isddd, t.ParamsP(), n.List.Slice(), 0, init)
-		setNodeSeq(&n.List, reorder1(ll))
+		n.List.Set(reorder1(ll))
 
 	case OCALLFUNC:
 		if n.Left.Op == OCLOSURE {
@@ -647,7 +646,7 @@
 			// transformclosure already did all preparation work.
 
 			// Prepend captured variables to argument list.
-			setNodeSeq(&n.List, append(n.Left.Func.Enter.Slice(), nodeSeqSlice(n.List)...))
+			n.List.Set(append(n.Left.Func.Enter.Slice(), n.List.Slice()...))
 
 			n.Left.Func.Enter.Set(nil)
 
@@ -668,7 +667,7 @@
 		}
 
 		t := n.Left.Type
-		if nodeSeqLen(n.List) != 0 && nodeSeqFirst(n.List).Op == OAS {
+		if n.List.Len() != 0 && n.List.First().Op == OAS {
 			break
 		}
 
@@ -679,18 +678,18 @@
 			switch Thearch.Thechar {
 			case '5', '6', '7':
 				n.Op = OSQRT
-				n.Left = nodeSeqFirst(n.List)
-				setNodeSeq(&n.List, nil)
+				n.Left = n.List.First()
+				n.List.Set(nil)
 				break opswitch
 			}
 		}
 
 		ll := ascompatte(n.Op, n, n.Isddd, t.ParamsP(), n.List.Slice(), 0, init)
-		setNodeSeq(&n.List, reorder1(ll))
+		n.List.Set(reorder1(ll))
 
 	case OCALLMETH:
 		t := n.Left.Type
-		if nodeSeqLen(n.List) != 0 && nodeSeqFirst(n.List).Op == OAS {
+		if n.List.Len() != 0 && n.List.First().Op == OAS {
 			break
 		}
 		walkexpr(&n.Left, init)
@@ -700,7 +699,7 @@
 		ll = append(ll, lr...)
 		n.Left.Left = nil
 		ullmancalc(n.Left)
-		setNodeSeq(&n.List, reorder1(ll))
+		n.List.Set(reorder1(ll))
 
 	case OAS:
 		init.AppendNodes(&n.Ninit)
@@ -799,7 +798,7 @@
 	case OAS2FUNC:
 		init.AppendNodes(&n.Ninit)
 
-		r := nodeSeqFirst(n.Rlist)
+		r := n.Rlist.First()
 		walkexprlistsafe(n.List.Slice(), init)
 		walkexpr(&r, init)
 
@@ -814,26 +813,26 @@
 	case OAS2RECV:
 		init.AppendNodes(&n.Ninit)
 
-		r := nodeSeqFirst(n.Rlist)
+		r := n.Rlist.First()
 		walkexprlistsafe(n.List.Slice(), init)
 		walkexpr(&r.Left, init)
 		var n1 *Node
-		if isblank(nodeSeqFirst(n.List)) {
+		if isblank(n.List.First()) {
 			n1 = nodnil()
 		} else {
-			n1 = Nod(OADDR, nodeSeqFirst(n.List), nil)
+			n1 = Nod(OADDR, n.List.First(), nil)
 		}
 		n1.Etype = 1 // addr does not escape
 		fn := chanfn("chanrecv2", 2, r.Left.Type)
-		r = mkcall1(fn, nodeSeqSecond(n.List).Type, init, typename(r.Left.Type), r.Left, n1)
-		n = Nod(OAS, nodeSeqSecond(n.List), r)
+		r = mkcall1(fn, n.List.Second().Type, init, typename(r.Left.Type), r.Left, n1)
+		n = Nod(OAS, n.List.Second(), r)
 		typecheck(&n, Etop)
 
 		// a,b = m[i];
 	case OAS2MAPR:
 		init.AppendNodes(&n.Ninit)
 
-		r := nodeSeqFirst(n.Rlist)
+		r := n.Rlist.First()
 		walkexprlistsafe(n.List.Slice(), init)
 		walkexpr(&r.Left, init)
 		walkexpr(&r.Right, init)
@@ -867,7 +866,7 @@
 		// to:
 		//   var,b = mapaccess2*(t, m, i)
 		//   a = *var
-		a := nodeSeqFirst(n.List)
+		a := n.List.First()
 
 		fn := mapfn(p, t)
 		r = mkcall1(fn, fn.Type.Results(), init, typename(t), r.Left, key)
@@ -875,8 +874,8 @@
 		// mapaccess2* returns a typed bool, but due to spec changes,
 		// the boolean result of i.(T) is now untyped so we make it the
 		// same type as the variable on the lhs.
-		if !isblank(nodeSeqSecond(n.List)) {
-			r.Type.Type.Down.Type = nodeSeqSecond(n.List).Type
+		if !isblank(n.List.Second()) {
+			r.Type.Type.Down.Type = n.List.Second().Type
 		}
 		setNodeSeq(&n.Rlist, list1(r))
 		n.Op = OAS2FUNC
@@ -899,8 +898,8 @@
 
 	case ODELETE:
 		init.AppendNodes(&n.Ninit)
-		map_ := nodeSeqFirst(n.List)
-		key := nodeSeqSecond(n.List)
+		map_ := n.List.First()
+		key := n.List.Second()
 		walkexpr(&map_, init)
 		walkexpr(&key, init)
 
@@ -911,7 +910,7 @@
 		n = mkcall1(mapfndel("mapdelete", t), nil, init, typename(t), map_, key)
 
 	case OAS2DOTTYPE:
-		e := nodeSeqFirst(n.Rlist) // i.(T)
+		e := n.Rlist.First() // i.(T)
 		// TODO(rsc): The Isfat is for consistency with componentgen and orderexpr.
 		// It needs to be removed in all three places.
 		// That would allow inlining x.(struct{*int}) the same as x.(*int).
@@ -932,7 +931,7 @@
 		from := e.Left // i
 
 		oktype := Types[TBOOL]
-		ok := nodeSeqSecond(n.List)
+		ok := n.List.Second()
 		if !isblank(ok) {
 			oktype = ok.Type
 		}
@@ -943,7 +942,7 @@
 		// Avoid runtime calls in a few cases of the form _, ok := i.(T).
 		// This is faster and shorter and allows the corresponding assertX2X2
 		// routines to skip nil checks on their last argument.
-		if isblank(nodeSeqFirst(n.List)) {
+		if isblank(n.List.First()) {
 			var fast *Node
 			switch {
 			case fromKind == 'E' && toKind == 'T':
@@ -967,10 +966,10 @@
 		}
 
 		var resptr *Node // &res
-		if isblank(nodeSeqFirst(n.List)) {
+		if isblank(n.List.First()) {
 			resptr = nodnil()
 		} else {
-			resptr = Nod(OADDR, nodeSeqFirst(n.List), nil)
+			resptr = Nod(OADDR, n.List.First(), nil)
 		}
 		resptr.Etype = 1 // addr does not escape
 
@@ -1344,9 +1343,9 @@
 		}
 
 		// s + "badgerbadgerbadger" == "badgerbadgerbadger"
-		if (Op(n.Etype) == OEQ || Op(n.Etype) == ONE) && Isconst(n.Right, CTSTR) && n.Left.Op == OADDSTR && nodeSeqLen(n.Left.List) == 2 && Isconst(nodeSeqSecond(n.Left.List), CTSTR) && strlit(n.Right) == strlit(nodeSeqSecond(n.Left.List)) {
+		if (Op(n.Etype) == OEQ || Op(n.Etype) == ONE) && Isconst(n.Right, CTSTR) && n.Left.Op == OADDSTR && n.Left.List.Len() == 2 && Isconst(n.Left.List.Second(), CTSTR) && strlit(n.Right) == strlit(n.Left.List.Second()) {
 			// TODO(marvin): Fix Node.EType type union.
-			r := Nod(Op(n.Etype), Nod(OLEN, nodeSeqFirst(n.Left.List), nil), Nodintconst(0))
+			r := Nod(Op(n.Etype), Nod(OLEN, n.Left.List.First(), nil), Nodintconst(0))
 			typecheck(&r, Erv)
 			walkexpr(&r, init)
 			r.Type = n.Type
@@ -1654,11 +1653,11 @@
 	//	expr-list = expr-list
 
 	// ensure order of evaluation for function calls
-	for nlit := nodeSeqIterate(nl); !nlit.Done(); nlit.Next() {
-		*nlit.P() = safeexpr(nlit.N(), init)
+	for i := range nl {
+		nl[i] = safeexpr(nl[i], init)
 	}
-	for nrit := nodeSeqIterate(nr); !nrit.Done(); nrit.Next() {
-		*nrit.P() = safeexpr(nrit.N(), init)
+	for i1 := range nr {
+		nr[i1] = safeexpr(nr[i1], init)
 	}
 
 	var nn []*Node
@@ -1751,7 +1750,7 @@
 	}
 
 	if !it.Done() || r != nil {
-		Yyerror("ascompatet: assignment count mismatch: %d = %d", nodeSeqLen(nl), structcount(*nr))
+		Yyerror("ascompatet: assignment count mismatch: %d = %d", nl.Len(), structcount(*nr))
 	}
 
 	if ucount != 0 {
@@ -1780,7 +1779,7 @@
 		if ddd != nil && prealloc[ddd] != nil {
 			prealloc[n] = prealloc[ddd] // temporary to use
 		}
-		setNodeSeq(&n.List, lr0)
+		n.List.Set(lr0)
 		n.Esc = esc
 		typecheck(&n, Erv)
 		if n.Type == nil {
@@ -1820,8 +1819,7 @@
 	fmt_ := ""
 	fmt_ += "\t"
 	first := 1
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		r = it.N()
+	for _, r = range l {
 		if first != 0 {
 			first = 0
 		} else {
@@ -1874,8 +1872,8 @@
 		}
 
 		a = Nod(OAS2, nil, nil)
-		setNodeSeq(&a.List, alist)
-		setNodeSeq(&a.Rlist, lr)
+		a.List.Set(alist)
+		a.Rlist.Set(lr)
 		typecheck(&a, Etop)
 		walkstmt(&a)
 		init.Append(a)
@@ -1962,15 +1960,14 @@
 	walkexprlistcheap(all.Slice(), init)
 
 	calls = append(calls, mkcall("printlock", nil, init))
-
-	for it := nodeSeqIterate(all); !it.Done(); it.Next() {
+	for i1, n1 := range all.Slice() {
 		if notfirst {
 			calls = append(calls, mkcall("printsp", nil, init))
 		}
 
 		notfirst = op == OPRINTN
 
-		n = it.N()
+		n = n1
 		if n.Op == OLITERAL {
 			switch n.Val().Ctype() {
 			case CTRUNE:
@@ -1988,7 +1985,7 @@
 			defaultlit(&n, Types[TINT64])
 		}
 		defaultlit(&n, nil)
-		*it.P() = n
+		all.Slice()[i1] = n
 		if n.Type == nil || n.Type.Etype == TFORW {
 			continue
 		}
@@ -2045,7 +2042,7 @@
 		}
 
 		r = Nod(OCALL, on, nil)
-		appendNodeSeqNode(&r.List, n)
+		r.List.Append(n)
 		calls = append(calls, r)
 	}
 
@@ -2061,7 +2058,7 @@
 	r = Nod(OEMPTY, nil, nil)
 	typecheck(&r, Etop)
 	walkexpr(&r, init)
-	setNodeSeq(&r.Ninit, calls)
+	r.Ninit.Set(calls)
 	return r
 }
 
@@ -2532,8 +2529,8 @@
 	if vmatch2(l, r.Right) {
 		return true
 	}
-	for it := nodeSeqIterate(r.List); !it.Done(); it.Next() {
-		if vmatch2(l, it.N()) {
+	for _, n := range r.List.Slice() {
+		if vmatch2(l, n) {
 			return true
 		}
 	}
@@ -2573,8 +2570,8 @@
 	if vmatch1(l.Right, r) {
 		return true
 	}
-	for it := nodeSeqIterate(l.List); !it.Done(); it.Next() {
-		if vmatch1(it.N(), r) {
+	for _, n := range l.List.Slice() {
+		if vmatch1(n, r) {
 			return true
 		}
 	}
@@ -2667,7 +2664,7 @@
 	n := fn.Type.Intuple
 
 	r := Nod(OCALL, fn, nil)
-	setNodeSeq(&r.List, va[:n])
+	r.List.Set(va[:n])
 	if fn.Type.Outtuple > 0 {
 		typecheck(&r, Erv|Efnstruct)
 	} else {
@@ -2738,7 +2735,7 @@
 
 func addstr(n *Node, init *Nodes) *Node {
 	// orderexpr rewrote OADDSTR to have a list of strings.
-	c := nodeSeqLen(n.List)
+	c := n.List.Len()
 
 	if c < 2 {
 		Yyerror("addstr count %d too small", c)
@@ -2747,9 +2744,9 @@
 	buf := nodnil()
 	if n.Esc == EscNone {
 		sz := int64(0)
-		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-			if it.N().Op == OLITERAL {
-				sz += int64(len(it.N().Val().U.(string)))
+		for _, n1 := range n.List.Slice() {
+			if n1.Op == OLITERAL {
+				sz += int64(len(n1.Val().U.(string)))
 			}
 		}
 
@@ -2764,9 +2761,8 @@
 
 	// build list of string arguments
 	args := []*Node{buf}
-
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		args = append(args, conv(it.N(), Types[TSTRING]))
+	for _, n2 := range n.List.Slice() {
+		args = append(args, conv(n2, Types[TSTRING]))
 	}
 
 	var fn string
@@ -2785,7 +2781,7 @@
 		if prealloc[n] != nil {
 			prealloc[slice] = prealloc[n]
 		}
-		setNodeSeq(&slice.List, args[1:]) // skip buf arg
+		slice.List.Set(args[1:]) // skip buf arg
 		args = []*Node{buf}
 		args = append(args, slice)
 		slice.Esc = EscNone
@@ -2793,7 +2789,7 @@
 
 	cat := syslook(fn)
 	r := Nod(OCALL, cat, nil)
-	setNodeSeq(&r.List, args)
+	r.List.Set(args)
 	typecheck(&r, Erv)
 	walkexpr(&r, init)
 	r.Type = n.Type
@@ -2815,16 +2811,18 @@
 // l2 is allowed to be a string.
 func appendslice(n *Node, init *Nodes) *Node {
 	walkexprlistsafe(n.List.Slice(), init)
+	for i1 := range
 
 	// 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 it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
-		*it.P() = cheapexpr(it.N(), init)
+	n.List.Slice() {
+		n.List.Slice()[i1] = cheapexpr(n.List.Slice()[i1],
+			init)
 	}
 
-	l1 := nodeSeqFirst(n.List)
-	l2 := nodeSeqSecond(n.List)
+	l1 := n.List.First()
+	l2 := n.List.Second()
 
 	s := temp(l1.Type) // var s []T
 	var l []*Node
@@ -2934,7 +2932,7 @@
 //   }
 //   s
 func walkappend(n *Node, init *Nodes, dst *Node) *Node {
-	if !samesafeexpr(dst, nodeSeqFirst(n.List)) {
+	if !samesafeexpr(dst, n.List.First()) {
 		it := nodeSeqIterate(n.List)
 		*it.P() = safeexpr(it.N(), init)
 		walkexpr(it.P(), init)
@@ -2953,13 +2951,13 @@
 		*it.P() = cheapexpr(it.N(), init)
 	}
 
-	nsrc := nodeSeqFirst(n.List)
+	nsrc := n.List.First()
 
 	// Resolve slice type of multi-valued return.
 	if Istype(nsrc.Type, TSTRUCT) {
 		nsrc.Type = nsrc.Type.Type.Type
 	}
-	argc := nodeSeqLen(n.List) - 1
+	argc := n.List.Len() - 1
 	if argc < 1 {
 		return nsrc
 	}
@@ -3098,9 +3096,9 @@
 	n := newname(sym)
 	n.Class = PFUNC
 	ntype := Nod(OTFUNC, nil, nil)
-	appendNodeSeqNode(&ntype.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
-	appendNodeSeqNode(&ntype.List, Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
-	appendNodeSeqNode(&ntype.Rlist, Nod(ODCLFIELD, nil, typenod(Types[TBOOL])))
+	ntype.List.Append(Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
+	ntype.List.Append(Nod(ODCLFIELD, nil, typenod(Ptrto(t))))
+	ntype.Rlist.Append(Nod(ODCLFIELD, nil, typenod(Types[TBOOL])))
 	typecheck(&ntype, Etype)
 	n.Type = ntype.Type
 	*needsize = 0
@@ -3153,9 +3151,9 @@
 		// x, ok := l.(type(r))
 		expr := Nod(OAS2, nil, nil)
 
-		appendNodeSeqNode(&expr.List, x)
-		appendNodeSeqNode(&expr.List, ok)
-		appendNodeSeqNode(&expr.Rlist, a)
+		expr.List.Append(x)
+		expr.List.Append(ok)
+		expr.Rlist.Append(a)
 		typecheck(&expr, Etop)
 		walkexpr(&expr, init)
 
@@ -3285,10 +3283,10 @@
 	var needsize int
 	call := Nod(OCALL, eqfor(t, &needsize), nil)
 
-	appendNodeSeqNode(&call.List, l)
-	appendNodeSeqNode(&call.List, r)
+	call.List.Append(l)
+	call.List.Append(r)
 	if needsize != 0 {
-		appendNodeSeqNode(&call.List, Nodintconst(t.Width))
+		call.List.Append(Nodintconst(t.Width))
 	}
 	r = call
 	if n.Op != OEQ {
@@ -3841,8 +3839,8 @@
 }
 
 func candiscardlist(l Nodes) bool {
-	for it := nodeSeqIterate(l); !it.Done(); it.Next() {
-		if !candiscard(it.N()) {
+	for _, n := range l.Slice() {
+		if !candiscard(n) {
 			return false
 		}
 	}
@@ -3955,7 +3953,7 @@
 func walkprintfunc(np **Node, init *Nodes) {
 	n := *np
 
-	if nodeSeqLen(n.Ninit) != 0 {
+	if n.Ninit.Len() != 0 {
 		walkstmtlist(n.Ninit.Slice())
 		init.AppendNodes(&n.Ninit)
 	}
@@ -3965,11 +3963,11 @@
 	var printargs []*Node
 	var a *Node
 	var buf string
-	for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
+	for _, n1 := range n.List.Slice() {
 		buf = fmt.Sprintf("a%d", num)
 		num++
-		a = Nod(ODCLFIELD, newname(Lookup(buf)), typenod(it.N().Type))
-		appendNodeSeqNode(&t.List, a)
+		a = Nod(ODCLFIELD, newname(Lookup(buf)), typenod(n1.Type))
+		t.List.Append(a)
 		printargs = append(printargs, a.Left)
 	}
 
@@ -3986,7 +3984,7 @@
 	funchdr(fn)
 
 	a = Nod(n.Op, nil, nil)
-	setNodeSeq(&a.List, printargs)
+	a.List.Set(printargs)
 	typecheck(&a, Etop)
 	walkstmt(&a)
 
@@ -4001,7 +3999,7 @@
 
 	a = Nod(OCALL, nil, nil)
 	a.Left = fn.Func.Nname
-	setNodeSeq(&a.List, n.List)
+	a.List.Set(n.List.Slice())
 	typecheck(&a, Etop)
 	walkexpr(&a, init)
 	*np = a