go/ssa/source_test.go - tools - Git at Google

 // Copyright 2013 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package ssa_test

 // This file defines tests of source-level debugging utilities.

 import (
 	"fmt"
 	"go/ast"
 	"go/constant"
 	"go/token"
 	"go/types"
 	"os"
 	"runtime"
 	"strings"
 	"testing"

 	"golang.org/x/tools/go/ast/astutil"
 	"golang.org/x/tools/go/expect"
 	"golang.org/x/tools/go/ssa"
 )

 func TestObjValueLookup(t *testing.T) {
 	if runtime.GOOS == "android" {
 		t.Skipf("no testdata directory on %s", runtime.GOOS)
 	}

 	src, err := os.ReadFile("testdata/objlookup.go")
 	if err != nil {
 		t.Fatal(err)
 	}
 	readFile := func(filename string) ([]byte, error) { return src, nil }

 	mode := ssa.GlobalDebug /*|ssa.PrintFunctions*/
 	mainPkg, ppkg := buildPackage(t, string(src), mode)
 	fset := ppkg.Fset

 	// Maps each var Ident (represented "name:linenum") to the
 	// kind of ssa.Value we expect (represented "Constant", "&Alloc").
 	expectations := make(map[string]string)

 	// Each note of the form @ssa(x, "BinOp") in testdata/objlookup.go
 	// specifies an expectation that an object named x declared on the
 	// same line is associated with an ssa.Value of type *ssa.BinOp.
 	notes, err := expect.ExtractGo(fset, ppkg.Syntax[0])
 	if err != nil {
 		t.Fatal(err)
 	}
 	for _, n := range notes {
 		if n.Name != "ssa" {
 			t.Errorf("%v: unexpected note type %q, want \"ssa\"", fset.Position(n.Pos), n.Name)
 			continue
 		}
 		if len(n.Args) != 2 {
 			t.Errorf("%v: ssa has %d args, want 2", fset.Position(n.Pos), len(n.Args))
 			continue
 		}
 		ident, ok := n.Args[0].(expect.Identifier)
 		if !ok {
 			t.Errorf("%v: got %v for arg 1, want identifier", fset.Position(n.Pos), n.Args[0])
 			continue
 		}
 		exp, ok := n.Args[1].(string)
 		if !ok {
 			t.Errorf("%v: got %v for arg 2, want string", fset.Position(n.Pos), n.Args[1])
 			continue
 		}
 		p, _, err := expect.MatchBefore(fset, readFile, n.Pos, string(ident))
 		if err != nil {
 			t.Error(err)
 			continue
 		}
 		pos := fset.Position(p)
 		key := fmt.Sprintf("%s:%d", ident, pos.Line)
 		expectations[key] = exp
 	}

 	var varIds []*ast.Ident
 	var varObjs []*types.Var
 	for id, obj := range ppkg.TypesInfo.Defs {
 		// Check invariants for func and const objects.
 		switch obj := obj.(type) {
 		case *types.Func:
 			checkFuncValue(t, mainPkg.Prog, obj)

 		case *types.Const:
 			checkConstValue(t, mainPkg.Prog, obj)

 		case *types.Var:
 			if id.Name == "_" {
 				continue
 			}
 			varIds = append(varIds, id)
 			varObjs = append(varObjs, obj)
 		}
 	}
 	for id, obj := range ppkg.TypesInfo.Uses {
 		if obj, ok := obj.(*types.Var); ok {
 			varIds = append(varIds, id)
 			varObjs = append(varObjs, obj)
 		}
 	}

 	// Check invariants for var objects.
 	// The result varies based on the specific Ident.
 	for i, id := range varIds {
 		obj := varObjs[i]
 		ref, _ := astutil.PathEnclosingInterval(ppkg.Syntax[0], id.Pos(), id.Pos())
 		pos := fset.Position(id.Pos())
 		exp := expectations[fmt.Sprintf("%s:%d", id.Name, pos.Line)]
 		if exp == "" {
 			t.Errorf("%s: no expectation for var ident %s ", pos, id.Name)
 			continue
 		}
 		wantAddr := false
 		if exp[0] == '&' {
 			wantAddr = true
 			exp = exp[1:]
 		}
 		checkVarValue(t, mainPkg, ref, obj, exp, wantAddr)
 	}
 }

 func checkFuncValue(t *testing.T, prog *ssa.Program, obj *types.Func) {
 	fn := prog.FuncValue(obj)
 	// fmt.Printf("FuncValue(%s) = %s\n", obj, fn) // debugging
 	if fn == nil {
 		if obj.Name() != "interfaceMethod" {
 			t.Errorf("FuncValue(%s) == nil", obj)
 		}
 		return
 	}
 	if fnobj := fn.Object(); fnobj != obj {
 		t.Errorf("FuncValue(%s).Object() == %s; value was %s",
 			obj, fnobj, fn.Name())
 		return
 	}
 	if !types.Identical(fn.Type(), obj.Type()) {
 		t.Errorf("FuncValue(%s).Type() == %s", obj, fn.Type())
 		return
 	}
 }

 func checkConstValue(t *testing.T, prog *ssa.Program, obj *types.Const) {
 	c := prog.ConstValue(obj)
 	// fmt.Printf("ConstValue(%s) = %s\n", obj, c) // debugging
 	if c == nil {
 		t.Errorf("ConstValue(%s) == nil", obj)
 		return
 	}
 	if !types.Identical(c.Type(), obj.Type()) {
 		t.Errorf("ConstValue(%s).Type() == %s", obj, c.Type())
 		return
 	}
 	if obj.Name() != "nil" {
 		if !constant.Compare(c.Value, token.EQL, obj.Val()) {
 			t.Errorf("ConstValue(%s).Value (%s) != %s",
 				obj, c.Value, obj.Val())
 			return
 		}
 	}
 }

 func checkVarValue(t *testing.T, pkg *ssa.Package, ref []ast.Node, obj *types.Var, expKind string, wantAddr bool) {
 	// The prefix of all assertions messages.
 	prefix := fmt.Sprintf("VarValue(%s @ L%d)",
 		obj, pkg.Prog.Fset.Position(ref[0].Pos()).Line)

 	v, gotAddr := pkg.Prog.VarValue(obj, pkg, ref)

 	// Kind is the concrete type of the ssa Value.
 	gotKind := "nil"
 	if v != nil {
 		gotKind = fmt.Sprintf("%T", v)[len("*ssa."):]
 	}

 	// fmt.Printf("%s = %v (kind %q; expect %q) wantAddr=%t gotAddr=%t\n", prefix, v, gotKind, expKind, wantAddr, gotAddr) // debugging

 	// Check the kinds match.
 	// "nil" indicates expected failure (e.g. optimized away).
 	if expKind != gotKind {
 		t.Errorf("%s concrete type == %s, want %s", prefix, gotKind, expKind)
 	}

 	// Check the types match.
 	// If wantAddr, the expected type is the object's address.
 	if v != nil {
 		expType := obj.Type()
 		if wantAddr {
 			expType = types.NewPointer(expType)
 			if !gotAddr {
 				t.Errorf("%s: got value, want address", prefix)
 			}
 		} else if gotAddr {
 			t.Errorf("%s: got address, want value", prefix)
 		}
 		if !types.Identical(v.Type(), expType) {
 			t.Errorf("%s.Type() == %s, want %s", prefix, v.Type(), expType)
 		}
 	}
 }

 // Ensure that, in debug mode, we can determine the ssa.Value
 // corresponding to every ast.Expr.
 func TestValueForExpr(t *testing.T) {
 	testValueForExpr(t, "testdata/valueforexpr.go")
 }

 func TestValueForExprStructConv(t *testing.T) {
 	testValueForExpr(t, "testdata/structconv.go")
 }

 func testValueForExpr(t *testing.T, testfile string) {
 	if runtime.GOOS == "android" {
 		t.Skipf("no testdata dir on %s", runtime.GOOS)
 	}

 	src, err := os.ReadFile(testfile)
 	if err != nil {
 		t.Fatal(err)
 	}

 	mode := ssa.GlobalDebug /*|ssa.PrintFunctions*/
 	mainPkg, ppkg := buildPackage(t, string(src), mode)
 	fset, file := ppkg.Fset, ppkg.Syntax[0]

 	if false {
 		// debugging
 		for _, mem := range mainPkg.Members {
 			if fn, ok := mem.(*ssa.Function); ok {
 				fn.WriteTo(os.Stderr)
 			}
 		}
 	}

 	var parenExprs []*ast.ParenExpr
 	ast.Inspect(file, func(n ast.Node) bool {
 		if n != nil {
 			if e, ok := n.(*ast.ParenExpr); ok {
 				parenExprs = append(parenExprs, e)
 			}
 		}
 		return true
 	})

 	notes, err := expect.ExtractGo(fset, file)
 	if err != nil {
 		t.Fatal(err)
 	}
 	for _, n := range notes {
 		want := n.Name
 		if want == "nil" {
 			want = "<nil>"
 		}
 		position := fset.Position(n.Pos)
 		var e ast.Expr
 		for _, paren := range parenExprs {
 			if paren.Pos() > n.Pos {
 				e = paren.X
 				break
 			}
 		}
 		if e == nil {
 			t.Errorf("%s: note doesn't precede ParenExpr: %q", position, want)
 			continue
 		}

 		path, _ := astutil.PathEnclosingInterval(file, n.Pos, n.Pos)
 		if path == nil {
 			t.Errorf("%s: can't find AST path from root to comment: %s", position, want)
 			continue
 		}

 		fn := ssa.EnclosingFunction(mainPkg, path)
 		if fn == nil {
 			t.Errorf("%s: can't find enclosing function", position)
 			continue
 		}

 		v, gotAddr := fn.ValueForExpr(e) // (may be nil)
 		got := strings.TrimPrefix(fmt.Sprintf("%T", v), "*ssa.")
 		if got != want {
 			t.Errorf("%s: got value %q, want %q", position, got, want)
 		}
 		if v != nil {
 			T := v.Type()
 			if gotAddr {
 				T = T.Underlying().(*types.Pointer).Elem() // deref
 			}
 			if etyp := ppkg.TypesInfo.TypeOf(e); !types.Identical(T, etyp) {
 				t.Errorf("%s: got type %s, want %s", position, etyp, T)
 			}
 		}
 	}
 }

 func TestEnclosingFunction(t *testing.T) {
 	tests := []struct {
 		desc   string
 		input  string // the input file
 		substr string // first occurrence of this string denotes interval
 		fn     string // name of expected containing function
 	}{
 		// We use distinctive numbers as syntactic landmarks.
 		{"Ordinary function", `
 		  package main
 		  func f() { println(1003) }`,
 			"100", "main.f"},
 		{"Methods", `
 		  package main
           type T int
 		  func (t T) f() { println(200) }`,
 			"200", "(main.T).f"},
 		{"Function literal", `
 		  package main
 		  func f() { println(func() { print(300) }) }`,
 			"300", "main.f$1"},
 		{"Doubly nested", `
 		  package main
 		  func f() { println(func() { print(func() { print(350) })})}`,
 			"350", "main.f$1$1"},
 		{"Implicit init for package-level var initializer", `
 		  package main; var a = 400`,
 			"400", "main.init"},
 		{"No code for constants", "package main; const a = 500", "500", "(none)"},
 		{" Explicit init", "package main; func init() { println(600) }", "600", "main.init#1"},
 		{"Multiple explicit init functions", `
 		  package main
 		  func init() { println("foo") }
 		  func init() { println(800) }`,
 			"800", "main.init#2"},
 		{"init containing FuncLit", `
 		  package main
 		  func init() { println(func(){print(900)}) }`,
 			"900", "main.init#1$1"},
 		{"generic", `
 		    package main
 			type S[T any] struct{}
 			func (*S[T]) Foo() { println(1000) }
 			type P[T any] struct{ *S[T] }`,
 			"1000", "(*main.S[T]).Foo",
 		},
 	}
 	for _, test := range tests {
 		t.Run(test.desc, func(t *testing.T) {
 			pkg, ppkg := buildPackage(t, test.input, ssa.BuilderMode(0))
 			fset, file := ppkg.Fset, ppkg.Syntax[0]

 			// Find [start,end) positions of the first occurrence of substr in file.
 			index := strings.Index(test.input, test.substr)
 			if index < 0 {
 				t.Fatalf("%q is not a substring of input", test.substr)
 			}
 			filePos := fset.File(file.Package)
 			start, end := filePos.Pos(index), filePos.Pos(index+len(test.substr))

 			path, exact := astutil.PathEnclosingInterval(file, start, end)
 			if !exact {
 				t.Fatalf("PathEnclosingInterval(%q) not exact", test.substr)
 			}

 			name := "(none)"
 			fn := ssa.EnclosingFunction(pkg, path)
 			if fn != nil {
 				name = fn.String()
 			}

 			if name != test.fn {
 				t.Errorf("EnclosingFunction(%q in %q) got %s, want %s",
 					test.substr, test.input, name, test.fn)
 			}

 			// While we're here: test HasEnclosingFunction.
 			if has := ssa.HasEnclosingFunction(pkg, path); has != (fn != nil) {
 				t.Errorf("HasEnclosingFunction(%q in %q) got %v, want %v",
 					test.substr, test.input, has, fn != nil)
 			}
 		})
 	}
 }
	// Copyright 2013 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package ssa_test

	// This file defines tests of source-level debugging utilities.

	import (
	"fmt"
	"go/ast"
	"go/constant"
	"go/token"
	"go/types"
	"os"
	"runtime"
	"strings"
	"testing"

	"golang.org/x/tools/go/ast/astutil"
	"golang.org/x/tools/go/expect"
	"golang.org/x/tools/go/ssa"
	)

	func TestObjValueLookup(t *testing.T) {
	if runtime.GOOS == "android" {
	t.Skipf("no testdata directory on %s", runtime.GOOS)
	}

	src, err := os.ReadFile("testdata/objlookup.go")
	if err != nil {
	t.Fatal(err)
	}
	readFile := func(filename string) ([]byte, error) { return src, nil }

	mode := ssa.GlobalDebug /\|ssa.PrintFunctions/
	mainPkg, ppkg := buildPackage(t, string(src), mode)
	fset := ppkg.Fset

	// Maps each var Ident (represented "name:linenum") to the
	// kind of ssa.Value we expect (represented "Constant", "&Alloc").
	expectations := make(map[string]string)

	// Each note of the form @ssa(x, "BinOp") in testdata/objlookup.go
	// specifies an expectation that an object named x declared on the
	// same line is associated with an ssa.Value of type *ssa.BinOp.
	notes, err := expect.ExtractGo(fset, ppkg.Syntax[0])
	if err != nil {
	t.Fatal(err)
	}
	for _, n := range notes {
	if n.Name != "ssa" {
	t.Errorf("%v: unexpected note type %q, want \"ssa\"", fset.Position(n.Pos), n.Name)
	continue
	}
	if len(n.Args) != 2 {
	t.Errorf("%v: ssa has %d args, want 2", fset.Position(n.Pos), len(n.Args))
	continue
	}
	ident, ok := n.Args[0].(expect.Identifier)
	if !ok {
	t.Errorf("%v: got %v for arg 1, want identifier", fset.Position(n.Pos), n.Args[0])
	continue
	}
	exp, ok := n.Args[1].(string)
	if !ok {
	t.Errorf("%v: got %v for arg 2, want string", fset.Position(n.Pos), n.Args[1])
	continue
	}
	p, _, err := expect.MatchBefore(fset, readFile, n.Pos, string(ident))
	if err != nil {
	t.Error(err)
	continue
	}
	pos := fset.Position(p)
	key := fmt.Sprintf("%s:%d", ident, pos.Line)
	expectations[key] = exp
	}

	var varIds []*ast.Ident
	var varObjs []*types.Var
	for id, obj := range ppkg.TypesInfo.Defs {
	// Check invariants for func and const objects.
	switch obj := obj.(type) {
	case *types.Func:
	checkFuncValue(t, mainPkg.Prog, obj)

	case *types.Const:
	checkConstValue(t, mainPkg.Prog, obj)

	case *types.Var:
	if id.Name == "_" {
	continue
	}
	varIds = append(varIds, id)
	varObjs = append(varObjs, obj)
	}
	}
	for id, obj := range ppkg.TypesInfo.Uses {
	if obj, ok := obj.(*types.Var); ok {
	varIds = append(varIds, id)
	varObjs = append(varObjs, obj)
	}
	}

	// Check invariants for var objects.
	// The result varies based on the specific Ident.
	for i, id := range varIds {
	obj := varObjs[i]
	ref, _ := astutil.PathEnclosingInterval(ppkg.Syntax[0], id.Pos(), id.Pos())
	pos := fset.Position(id.Pos())
	exp := expectations[fmt.Sprintf("%s:%d", id.Name, pos.Line)]
	if exp == "" {
	t.Errorf("%s: no expectation for var ident %s ", pos, id.Name)
	continue
	}
	wantAddr := false
	if exp[0] == '&' {
	wantAddr = true
	exp = exp[1:]
	}
	checkVarValue(t, mainPkg, ref, obj, exp, wantAddr)
	}
	}

	func checkFuncValue(t testing.T, prog ssa.Program, obj *types.Func) {
	fn := prog.FuncValue(obj)
	// fmt.Printf("FuncValue(%s) = %s\n", obj, fn) // debugging
	if fn == nil {
	if obj.Name() != "interfaceMethod" {
	t.Errorf("FuncValue(%s) == nil", obj)
	}
	return
	}
	if fnobj := fn.Object(); fnobj != obj {
	t.Errorf("FuncValue(%s).Object() == %s; value was %s",
	obj, fnobj, fn.Name())
	return
	}
	if !types.Identical(fn.Type(), obj.Type()) {
	t.Errorf("FuncValue(%s).Type() == %s", obj, fn.Type())
	return
	}
	}

	func checkConstValue(t testing.T, prog ssa.Program, obj *types.Const) {
	c := prog.ConstValue(obj)
	// fmt.Printf("ConstValue(%s) = %s\n", obj, c) // debugging
	if c == nil {
	t.Errorf("ConstValue(%s) == nil", obj)
	return
	}
	if !types.Identical(c.Type(), obj.Type()) {
	t.Errorf("ConstValue(%s).Type() == %s", obj, c.Type())
	return
	}
	if obj.Name() != "nil" {
	if !constant.Compare(c.Value, token.EQL, obj.Val()) {
	t.Errorf("ConstValue(%s).Value (%s) != %s",
	obj, c.Value, obj.Val())
	return
	}
	}
	}

	func checkVarValue(t testing.T, pkg ssa.Package, ref []ast.Node, obj *types.Var, expKind string, wantAddr bool) {
	// The prefix of all assertions messages.
	prefix := fmt.Sprintf("VarValue(%s @ L%d)",
	obj, pkg.Prog.Fset.Position(ref[0].Pos()).Line)

	v, gotAddr := pkg.Prog.VarValue(obj, pkg, ref)

	// Kind is the concrete type of the ssa Value.
	gotKind := "nil"
	if v != nil {
	gotKind = fmt.Sprintf("%T", v)[len("*ssa."):]
	}

	// fmt.Printf("%s = %v (kind %q; expect %q) wantAddr=%t gotAddr=%t\n", prefix, v, gotKind, expKind, wantAddr, gotAddr) // debugging

	// Check the kinds match.
	// "nil" indicates expected failure (e.g. optimized away).
	if expKind != gotKind {
	t.Errorf("%s concrete type == %s, want %s", prefix, gotKind, expKind)
	}

	// Check the types match.
	// If wantAddr, the expected type is the object's address.
	if v != nil {
	expType := obj.Type()
	if wantAddr {
	expType = types.NewPointer(expType)
	if !gotAddr {
	t.Errorf("%s: got value, want address", prefix)
	}
	} else if gotAddr {
	t.Errorf("%s: got address, want value", prefix)
	}
	if !types.Identical(v.Type(), expType) {
	t.Errorf("%s.Type() == %s, want %s", prefix, v.Type(), expType)
	}
	}
	}

	// Ensure that, in debug mode, we can determine the ssa.Value
	// corresponding to every ast.Expr.
	func TestValueForExpr(t *testing.T) {
	testValueForExpr(t, "testdata/valueforexpr.go")
	}

	func TestValueForExprStructConv(t *testing.T) {
	testValueForExpr(t, "testdata/structconv.go")
	}

	func testValueForExpr(t *testing.T, testfile string) {
	if runtime.GOOS == "android" {
	t.Skipf("no testdata dir on %s", runtime.GOOS)
	}

	src, err := os.ReadFile(testfile)
	if err != nil {
	t.Fatal(err)
	}

	mode := ssa.GlobalDebug /\|ssa.PrintFunctions/
	mainPkg, ppkg := buildPackage(t, string(src), mode)
	fset, file := ppkg.Fset, ppkg.Syntax[0]

	if false {
	// debugging
	for _, mem := range mainPkg.Members {
	if fn, ok := mem.(*ssa.Function); ok {
	fn.WriteTo(os.Stderr)
	}
	}
	}

	var parenExprs []*ast.ParenExpr
	ast.Inspect(file, func(n ast.Node) bool {
	if n != nil {
	if e, ok := n.(*ast.ParenExpr); ok {
	parenExprs = append(parenExprs, e)
	}
	}
	return true
	})

	notes, err := expect.ExtractGo(fset, file)
	if err != nil {
	t.Fatal(err)
	}
	for _, n := range notes {
	want := n.Name
	if want == "nil" {
	want = "<nil>"
	}
	position := fset.Position(n.Pos)
	var e ast.Expr
	for _, paren := range parenExprs {
	if paren.Pos() > n.Pos {
	e = paren.X
	break
	}
	}
	if e == nil {
	t.Errorf("%s: note doesn't precede ParenExpr: %q", position, want)
	continue
	}

	path, _ := astutil.PathEnclosingInterval(file, n.Pos, n.Pos)
	if path == nil {
	t.Errorf("%s: can't find AST path from root to comment: %s", position, want)
	continue
	}

	fn := ssa.EnclosingFunction(mainPkg, path)
	if fn == nil {
	t.Errorf("%s: can't find enclosing function", position)
	continue
	}

	v, gotAddr := fn.ValueForExpr(e) // (may be nil)
	got := strings.TrimPrefix(fmt.Sprintf("%T", v), "*ssa.")
	if got != want {
	t.Errorf("%s: got value %q, want %q", position, got, want)
	}
	if v != nil {
	T := v.Type()
	if gotAddr {
	T = T.Underlying().(*types.Pointer).Elem() // deref
	}
	if etyp := ppkg.TypesInfo.TypeOf(e); !types.Identical(T, etyp) {
	t.Errorf("%s: got type %s, want %s", position, etyp, T)
	}
	}
	}
	}

	func TestEnclosingFunction(t *testing.T) {
	tests := []struct {
	desc string
	input string // the input file
	substr string // first occurrence of this string denotes interval
	fn string // name of expected containing function
	}{
	// We use distinctive numbers as syntactic landmarks.
	{"Ordinary function", `
	package main
	func f() { println(1003) }`,
	"100", "main.f"},
	{"Methods", `
	package main
	type T int
	func (t T) f() { println(200) }`,
	"200", "(main.T).f"},
	{"Function literal", `
	package main
	func f() { println(func() { print(300) }) }`,
	"300", "main.f$1"},
	{"Doubly nested", `
	package main
	func f() { println(func() { print(func() { print(350) })})}`,
	"350", "main.f$1$1"},
	{"Implicit init for package-level var initializer", `
	package main; var a = 400`,
	"400", "main.init"},
	{"No code for constants", "package main; const a = 500", "500", "(none)"},
	{" Explicit init", "package main; func init() { println(600) }", "600", "main.init#1"},
	{"Multiple explicit init functions", `
	package main
	func init() { println("foo") }
	func init() { println(800) }`,
	"800", "main.init#2"},
	{"init containing FuncLit", `
	package main
	func init() { println(func(){print(900)}) }`,
	"900", "main.init#1$1"},
	{"generic", `
	package main
	type S[T any] struct{}
	func (*S[T]) Foo() { println(1000) }
	type P[T any] struct{ *S[T] }`,
	"1000", "(*main.S[T]).Foo",
	},
	}
	for _, test := range tests {
	t.Run(test.desc, func(t *testing.T) {
	pkg, ppkg := buildPackage(t, test.input, ssa.BuilderMode(0))
	fset, file := ppkg.Fset, ppkg.Syntax[0]

	// Find [start,end) positions of the first occurrence of substr in file.
	index := strings.Index(test.input, test.substr)
	if index < 0 {
	t.Fatalf("%q is not a substring of input", test.substr)
	}
	filePos := fset.File(file.Package)
	start, end := filePos.Pos(index), filePos.Pos(index+len(test.substr))

	path, exact := astutil.PathEnclosingInterval(file, start, end)
	if !exact {
	t.Fatalf("PathEnclosingInterval(%q) not exact", test.substr)
	}

	name := "(none)"
	fn := ssa.EnclosingFunction(pkg, path)
	if fn != nil {
	name = fn.String()
	}

	if name != test.fn {
	t.Errorf("EnclosingFunction(%q in %q) got %s, want %s",
	test.substr, test.input, name, test.fn)
	}

	// While we're here: test HasEnclosingFunction.
	if has := ssa.HasEnclosingFunction(pkg, path); has != (fn != nil) {
	t.Errorf("HasEnclosingFunction(%q in %q) got %v, want %v",
	test.substr, test.input, has, fn != nil)
	}
	})
	}
	}