Source file src/go/types/issues_test.go

     1  // Copyright 2013 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // This file implements tests for various issues.
     6  
     7  package types_test
     8  
     9  import (
    10  	"fmt"
    11  	"go/ast"
    12  	"go/importer"
    13  	"go/parser"
    14  	"go/token"
    15  	"internal/testenv"
    16  	"regexp"
    17  	"slices"
    18  	"strings"
    19  	"testing"
    20  
    21  	. "go/types"
    22  )
    23  
    24  func TestIssue5770(t *testing.T) {
    25  	_, err := typecheck(`package p; type S struct{T}`, nil, nil)
    26  	const want = "undefined: T"
    27  	if err == nil || !strings.Contains(err.Error(), want) {
    28  		t.Errorf("got: %v; want: %s", err, want)
    29  	}
    30  }
    31  
    32  func TestIssue5849(t *testing.T) {
    33  	src := `
    34  package p
    35  var (
    36  	s uint
    37  	_ = uint8(8)
    38  	_ = uint16(16) << s
    39  	_ = uint32(32 << s)
    40  	_ = uint64(64 << s + s)
    41  	_ = (interface{})("foo")
    42  	_ = (interface{})(nil)
    43  )`
    44  	types := make(map[ast.Expr]TypeAndValue)
    45  	mustTypecheck(src, nil, &Info{Types: types})
    46  
    47  	for x, tv := range types {
    48  		var want Type
    49  		switch x := x.(type) {
    50  		case *ast.BasicLit:
    51  			switch x.Value {
    52  			case `8`:
    53  				want = Typ[Uint8]
    54  			case `16`:
    55  				want = Typ[Uint16]
    56  			case `32`:
    57  				want = Typ[Uint32]
    58  			case `64`:
    59  				want = Typ[Uint] // because of "+ s", s is of type uint
    60  			case `"foo"`:
    61  				want = Typ[String]
    62  			}
    63  		case *ast.Ident:
    64  			if x.Name == "nil" {
    65  				want = Typ[UntypedNil]
    66  			}
    67  		}
    68  		if want != nil && !Identical(tv.Type, want) {
    69  			t.Errorf("got %s; want %s", tv.Type, want)
    70  		}
    71  	}
    72  }
    73  
    74  func TestIssue6413(t *testing.T) {
    75  	src := `
    76  package p
    77  func f() int {
    78  	defer f()
    79  	go f()
    80  	return 0
    81  }
    82  `
    83  	types := make(map[ast.Expr]TypeAndValue)
    84  	mustTypecheck(src, nil, &Info{Types: types})
    85  
    86  	want := Typ[Int]
    87  	n := 0
    88  	for x, tv := range types {
    89  		if _, ok := x.(*ast.CallExpr); ok {
    90  			if tv.Type != want {
    91  				t.Errorf("%s: got %s; want %s", fset.Position(x.Pos()), tv.Type, want)
    92  			}
    93  			n++
    94  		}
    95  	}
    96  
    97  	if n != 2 {
    98  		t.Errorf("got %d CallExprs; want 2", n)
    99  	}
   100  }
   101  
   102  func TestIssue7245(t *testing.T) {
   103  	src := `
   104  package p
   105  func (T) m() (res bool) { return }
   106  type T struct{} // receiver type after method declaration
   107  `
   108  	f := mustParse(fset, src)
   109  
   110  	var conf Config
   111  	defs := make(map[*ast.Ident]Object)
   112  	_, err := conf.Check(f.Name.Name, fset, []*ast.File{f}, &Info{Defs: defs})
   113  	if err != nil {
   114  		t.Fatal(err)
   115  	}
   116  
   117  	m := f.Decls[0].(*ast.FuncDecl)
   118  	res1 := defs[m.Name].(*Func).Signature().Results().At(0)
   119  	res2 := defs[m.Type.Results.List[0].Names[0]].(*Var)
   120  
   121  	if res1 != res2 {
   122  		t.Errorf("got %s (%p) != %s (%p)", res1, res2, res1, res2)
   123  	}
   124  }
   125  
   126  // This tests that uses of existing vars on the LHS of an assignment
   127  // are Uses, not Defs; and also that the (illegal) use of a non-var on
   128  // the LHS of an assignment is a Use nonetheless.
   129  func TestIssue7827(t *testing.T) {
   130  	const src = `
   131  package p
   132  func _() {
   133  	const w = 1        // defs w
   134          x, y := 2, 3       // defs x, y
   135          w, x, z := 4, 5, 6 // uses w, x, defs z; error: cannot assign to w
   136          _, _, _ = x, y, z  // uses x, y, z
   137  }
   138  `
   139  	// We need a specific fileset in this test below for positions.
   140  	// Cannot use typecheck helper.
   141  	fset := token.NewFileSet()
   142  	f := mustParse(fset, src)
   143  
   144  	const want = `L3 defs func p._()
   145  L4 defs const w untyped int
   146  L5 defs var x int
   147  L5 defs var y int
   148  L6 defs var z int
   149  L6 uses const w untyped int
   150  L6 uses var x int
   151  L7 uses var x int
   152  L7 uses var y int
   153  L7 uses var z int`
   154  
   155  	// don't abort at the first error
   156  	conf := Config{Error: func(err error) { t.Log(err) }}
   157  	defs := make(map[*ast.Ident]Object)
   158  	uses := make(map[*ast.Ident]Object)
   159  	_, err := conf.Check(f.Name.Name, fset, []*ast.File{f}, &Info{Defs: defs, Uses: uses})
   160  	if s := err.Error(); !strings.HasSuffix(s, "cannot assign to w") {
   161  		t.Errorf("Check: unexpected error: %s", s)
   162  	}
   163  
   164  	var facts []string
   165  	for id, obj := range defs {
   166  		if obj != nil {
   167  			fact := fmt.Sprintf("L%d defs %s", fset.Position(id.Pos()).Line, obj)
   168  			facts = append(facts, fact)
   169  		}
   170  	}
   171  	for id, obj := range uses {
   172  		fact := fmt.Sprintf("L%d uses %s", fset.Position(id.Pos()).Line, obj)
   173  		facts = append(facts, fact)
   174  	}
   175  	slices.Sort(facts)
   176  
   177  	got := strings.Join(facts, "\n")
   178  	if got != want {
   179  		t.Errorf("Unexpected defs/uses\ngot:\n%s\nwant:\n%s", got, want)
   180  	}
   181  }
   182  
   183  // This tests that the package associated with the types.Object.Pkg method
   184  // is the type's package independent of the order in which the imports are
   185  // listed in the sources src1, src2 below.
   186  // The actual issue is in go/internal/gcimporter which has a corresponding
   187  // test; we leave this test here to verify correct behavior at the go/types
   188  // level.
   189  func TestIssue13898(t *testing.T) {
   190  	testenv.MustHaveGoBuild(t)
   191  
   192  	const src0 = `
   193  package main
   194  
   195  import "go/types"
   196  
   197  func main() {
   198  	var info types.Info
   199  	for _, obj := range info.Uses {
   200  		_ = obj.Pkg()
   201  	}
   202  }
   203  `
   204  	// like src0, but also imports go/importer
   205  	const src1 = `
   206  package main
   207  
   208  import (
   209  	"go/types"
   210  	_ "go/importer"
   211  )
   212  
   213  func main() {
   214  	var info types.Info
   215  	for _, obj := range info.Uses {
   216  		_ = obj.Pkg()
   217  	}
   218  }
   219  `
   220  	// like src1 but with different import order
   221  	// (used to fail with this issue)
   222  	const src2 = `
   223  package main
   224  
   225  import (
   226  	_ "go/importer"
   227  	"go/types"
   228  )
   229  
   230  func main() {
   231  	var info types.Info
   232  	for _, obj := range info.Uses {
   233  		_ = obj.Pkg()
   234  	}
   235  }
   236  `
   237  	f := func(test, src string) {
   238  		info := &Info{Uses: make(map[*ast.Ident]Object)}
   239  		mustTypecheck(src, nil, info)
   240  
   241  		var pkg *Package
   242  		count := 0
   243  		for id, obj := range info.Uses {
   244  			if id.Name == "Pkg" {
   245  				pkg = obj.Pkg()
   246  				count++
   247  			}
   248  		}
   249  		if count != 1 {
   250  			t.Fatalf("%s: got %d entries named Pkg; want 1", test, count)
   251  		}
   252  		if pkg.Name() != "types" {
   253  			t.Fatalf("%s: got %v; want package types", test, pkg)
   254  		}
   255  	}
   256  
   257  	f("src0", src0)
   258  	f("src1", src1)
   259  	f("src2", src2)
   260  }
   261  
   262  func TestIssue22525(t *testing.T) {
   263  	const src = `package p; func f() { var a, b, c, d, e int }`
   264  
   265  	got := "\n"
   266  	conf := Config{Error: func(err error) { got += err.Error() + "\n" }}
   267  	typecheck(src, &conf, nil) // do not crash
   268  	want := "\n" +
   269  		"p:1:27: declared and not used: a\n" +
   270  		"p:1:30: declared and not used: b\n" +
   271  		"p:1:33: declared and not used: c\n" +
   272  		"p:1:36: declared and not used: d\n" +
   273  		"p:1:39: declared and not used: e\n"
   274  	if got != want {
   275  		t.Errorf("got: %swant: %s", got, want)
   276  	}
   277  }
   278  
   279  func TestIssue25627(t *testing.T) {
   280  	const prefix = `package p; import "unsafe"; type P *struct{}; type I interface{}; type T `
   281  	// The src strings (without prefix) are constructed such that the number of semicolons
   282  	// plus one corresponds to the number of fields expected in the respective struct.
   283  	for _, src := range []string{
   284  		`struct { x Missing }`,
   285  		`struct { Missing }`,
   286  		`struct { *Missing }`,
   287  		`struct { unsafe.Pointer }`,
   288  		`struct { P }`,
   289  		`struct { *I }`,
   290  		`struct { a int; b Missing; *Missing }`,
   291  	} {
   292  		f := mustParse(fset, prefix+src)
   293  
   294  		cfg := Config{Importer: importer.Default(), Error: func(err error) {}}
   295  		info := &Info{Types: make(map[ast.Expr]TypeAndValue)}
   296  		_, err := cfg.Check(f.Name.Name, fset, []*ast.File{f}, info)
   297  		if err != nil {
   298  			if _, ok := err.(Error); !ok {
   299  				t.Fatal(err)
   300  			}
   301  		}
   302  
   303  		ast.Inspect(f, func(n ast.Node) bool {
   304  			if spec, _ := n.(*ast.TypeSpec); spec != nil {
   305  				if tv, ok := info.Types[spec.Type]; ok && spec.Name.Name == "T" {
   306  					want := strings.Count(src, ";") + 1
   307  					if got := tv.Type.(*Struct).NumFields(); got != want {
   308  						t.Errorf("%s: got %d fields; want %d", src, got, want)
   309  					}
   310  				}
   311  			}
   312  			return true
   313  		})
   314  	}
   315  }
   316  
   317  func TestIssue28005(t *testing.T) {
   318  	// method names must match defining interface name for this test
   319  	// (see last comment in this function)
   320  	sources := [...]string{
   321  		"package p; type A interface{ A() }",
   322  		"package p; type B interface{ B() }",
   323  		"package p; type X interface{ A; B }",
   324  	}
   325  
   326  	// compute original file ASTs
   327  	var orig [len(sources)]*ast.File
   328  	for i, src := range sources {
   329  		orig[i] = mustParse(fset, src)
   330  	}
   331  
   332  	// run the test for all order permutations of the incoming files
   333  	for _, perm := range [][len(sources)]int{
   334  		{0, 1, 2},
   335  		{0, 2, 1},
   336  		{1, 0, 2},
   337  		{1, 2, 0},
   338  		{2, 0, 1},
   339  		{2, 1, 0},
   340  	} {
   341  		// create file order permutation
   342  		files := make([]*ast.File, len(sources))
   343  		for i := range perm {
   344  			files[i] = orig[perm[i]]
   345  		}
   346  
   347  		// type-check package with given file order permutation
   348  		var conf Config
   349  		info := &Info{Defs: make(map[*ast.Ident]Object)}
   350  		_, err := conf.Check("", fset, files, info)
   351  		if err != nil {
   352  			t.Fatal(err)
   353  		}
   354  
   355  		// look for interface object X
   356  		var obj Object
   357  		for name, def := range info.Defs {
   358  			if name.Name == "X" {
   359  				obj = def
   360  				break
   361  			}
   362  		}
   363  		if obj == nil {
   364  			t.Fatal("object X not found")
   365  		}
   366  		iface := obj.Type().Underlying().(*Interface) // object X must be an interface
   367  
   368  		// Each iface method m is embedded; and m's receiver base type name
   369  		// must match the method's name per the choice in the source file.
   370  		for i := 0; i < iface.NumMethods(); i++ {
   371  			m := iface.Method(i)
   372  			recvName := m.Signature().Recv().Type().(*Named).Obj().Name()
   373  			if recvName != m.Name() {
   374  				t.Errorf("perm %v: got recv %s; want %s", perm, recvName, m.Name())
   375  			}
   376  		}
   377  	}
   378  }
   379  
   380  func TestIssue28282(t *testing.T) {
   381  	// create type interface { error }
   382  	et := Universe.Lookup("error").Type()
   383  	it := NewInterfaceType(nil, []Type{et})
   384  	it.Complete()
   385  	// verify that after completing the interface, the embedded method remains unchanged
   386  	want := et.Underlying().(*Interface).Method(0)
   387  	got := it.Method(0)
   388  	if got != want {
   389  		t.Fatalf("%s.Method(0): got %q (%p); want %q (%p)", it, got, got, want, want)
   390  	}
   391  	// verify that lookup finds the same method in both interfaces (redundant check)
   392  	obj, _, _ := LookupFieldOrMethod(et, false, nil, "Error")
   393  	if obj != want {
   394  		t.Fatalf("%s.Lookup: got %q (%p); want %q (%p)", et, obj, obj, want, want)
   395  	}
   396  	obj, _, _ = LookupFieldOrMethod(it, false, nil, "Error")
   397  	if obj != want {
   398  		t.Fatalf("%s.Lookup: got %q (%p); want %q (%p)", it, obj, obj, want, want)
   399  	}
   400  }
   401  
   402  func TestIssue29029(t *testing.T) {
   403  	f1 := mustParse(fset, `package p; type A interface { M() }`)
   404  	f2 := mustParse(fset, `package p; var B interface { A }`)
   405  
   406  	// printInfo prints the *Func definitions recorded in info, one *Func per line.
   407  	printInfo := func(info *Info) string {
   408  		var buf strings.Builder
   409  		for _, obj := range info.Defs {
   410  			if fn, ok := obj.(*Func); ok {
   411  				fmt.Fprintln(&buf, fn)
   412  			}
   413  		}
   414  		return buf.String()
   415  	}
   416  
   417  	// The *Func (method) definitions for package p must be the same
   418  	// independent on whether f1 and f2 are type-checked together, or
   419  	// incrementally.
   420  
   421  	// type-check together
   422  	var conf Config
   423  	info := &Info{Defs: make(map[*ast.Ident]Object)}
   424  	check := NewChecker(&conf, fset, NewPackage("", "p"), info)
   425  	if err := check.Files([]*ast.File{f1, f2}); err != nil {
   426  		t.Fatal(err)
   427  	}
   428  	want := printInfo(info)
   429  
   430  	// type-check incrementally
   431  	info = &Info{Defs: make(map[*ast.Ident]Object)}
   432  	check = NewChecker(&conf, fset, NewPackage("", "p"), info)
   433  	if err := check.Files([]*ast.File{f1}); err != nil {
   434  		t.Fatal(err)
   435  	}
   436  	if err := check.Files([]*ast.File{f2}); err != nil {
   437  		t.Fatal(err)
   438  	}
   439  	got := printInfo(info)
   440  
   441  	if got != want {
   442  		t.Errorf("\ngot : %swant: %s", got, want)
   443  	}
   444  }
   445  
   446  func TestIssue34151(t *testing.T) {
   447  	const asrc = `package a; type I interface{ M() }; type T struct { F interface { I } }`
   448  	const bsrc = `package b; import "a"; type T struct { F interface { a.I } }; var _ = a.T(T{})`
   449  
   450  	a := mustTypecheck(asrc, nil, nil)
   451  
   452  	conf := Config{Importer: importHelper{pkg: a}}
   453  	mustTypecheck(bsrc, &conf, nil)
   454  }
   455  
   456  type importHelper struct {
   457  	pkg      *Package
   458  	fallback Importer
   459  }
   460  
   461  func (h importHelper) Import(path string) (*Package, error) {
   462  	if path == h.pkg.Path() {
   463  		return h.pkg, nil
   464  	}
   465  	if h.fallback == nil {
   466  		return nil, fmt.Errorf("got package path %q; want %q", path, h.pkg.Path())
   467  	}
   468  	return h.fallback.Import(path)
   469  }
   470  
   471  // TestIssue34921 verifies that we don't update an imported type's underlying
   472  // type when resolving an underlying type. Specifically, when determining the
   473  // underlying type of b.T (which is the underlying type of a.T, which is int)
   474  // we must not set the underlying type of a.T again since that would lead to
   475  // a race condition if package b is imported elsewhere, in a package that is
   476  // concurrently type-checked.
   477  func TestIssue34921(t *testing.T) {
   478  	defer func() {
   479  		if r := recover(); r != nil {
   480  			t.Error(r)
   481  		}
   482  	}()
   483  
   484  	var sources = []string{
   485  		`package a; type T int`,
   486  		`package b; import "a"; type T a.T`,
   487  	}
   488  
   489  	var pkg *Package
   490  	for _, src := range sources {
   491  		conf := Config{Importer: importHelper{pkg: pkg}}
   492  		pkg = mustTypecheck(src, &conf, nil) // pkg imported by the next package in this test
   493  	}
   494  }
   495  
   496  func TestIssue43088(t *testing.T) {
   497  	// type T1 struct {
   498  	//         _ T2
   499  	// }
   500  	//
   501  	// type T2 struct {
   502  	//         _ struct {
   503  	//                 _ T2
   504  	//         }
   505  	// }
   506  	n1 := NewTypeName(nopos, nil, "T1", nil)
   507  	T1 := NewNamed(n1, nil, nil)
   508  	n2 := NewTypeName(nopos, nil, "T2", nil)
   509  	T2 := NewNamed(n2, nil, nil)
   510  	s1 := NewStruct([]*Var{NewField(nopos, nil, "_", T2, false)}, nil)
   511  	T1.SetUnderlying(s1)
   512  	s2 := NewStruct([]*Var{NewField(nopos, nil, "_", T2, false)}, nil)
   513  	s3 := NewStruct([]*Var{NewField(nopos, nil, "_", s2, false)}, nil)
   514  	T2.SetUnderlying(s3)
   515  
   516  	// These calls must terminate (no endless recursion).
   517  	Comparable(T1)
   518  	Comparable(T2)
   519  }
   520  
   521  func TestIssue44515(t *testing.T) {
   522  	typ := Unsafe.Scope().Lookup("Pointer").Type()
   523  
   524  	got := TypeString(typ, nil)
   525  	want := "unsafe.Pointer"
   526  	if got != want {
   527  		t.Errorf("got %q; want %q", got, want)
   528  	}
   529  
   530  	qf := func(pkg *Package) string {
   531  		if pkg == Unsafe {
   532  			return "foo"
   533  		}
   534  		return ""
   535  	}
   536  	got = TypeString(typ, qf)
   537  	want = "foo.Pointer"
   538  	if got != want {
   539  		t.Errorf("got %q; want %q", got, want)
   540  	}
   541  }
   542  
   543  func TestIssue43124(t *testing.T) {
   544  	// TODO(rFindley) move this to testdata by enhancing support for importing.
   545  
   546  	testenv.MustHaveGoBuild(t) // The go command is needed for the importer to determine the locations of stdlib .a files.
   547  
   548  	// All involved packages have the same name (template). Error messages should
   549  	// disambiguate between text/template and html/template by printing the full
   550  	// path.
   551  	const (
   552  		asrc = `package a; import "text/template"; func F(template.Template) {}; func G(int) {}`
   553  		bsrc = `
   554  package b
   555  
   556  import (
   557  	"a"
   558  	"html/template"
   559  )
   560  
   561  func _() {
   562  	// Packages should be fully qualified when there is ambiguity within the
   563  	// error string itself.
   564  	a.F(template /* ERRORx "cannot use.*html/template.* as .*text/template" */ .Template{})
   565  }
   566  `
   567  		csrc = `
   568  package c
   569  
   570  import (
   571  	"a"
   572  	"fmt"
   573  	"html/template"
   574  )
   575  
   576  // go.dev/issue/46905: make sure template is not the first package qualified.
   577  var _ fmt.Stringer = 1 // ERRORx "cannot use 1.*as fmt\\.Stringer"
   578  
   579  // Packages should be fully qualified when there is ambiguity in reachable
   580  // packages. In this case both a (and for that matter html/template) import
   581  // text/template.
   582  func _() { a.G(template /* ERRORx "cannot use .*html/template.*Template" */ .Template{}) }
   583  `
   584  
   585  		tsrc = `
   586  package template
   587  
   588  import "text/template"
   589  
   590  type T int
   591  
   592  // Verify that the current package name also causes disambiguation.
   593  var _ T = template /* ERRORx "cannot use.*text/template.* as T value" */.Template{}
   594  `
   595  	)
   596  
   597  	a := mustTypecheck(asrc, nil, nil)
   598  	imp := importHelper{pkg: a, fallback: importer.Default()}
   599  
   600  	withImporter := func(cfg *Config) {
   601  		cfg.Importer = imp
   602  	}
   603  
   604  	testFiles(t, []string{"b.go"}, [][]byte{[]byte(bsrc)}, false, withImporter)
   605  	testFiles(t, []string{"c.go"}, [][]byte{[]byte(csrc)}, false, withImporter)
   606  	testFiles(t, []string{"t.go"}, [][]byte{[]byte(tsrc)}, false, withImporter)
   607  }
   608  
   609  func TestIssue50646(t *testing.T) {
   610  	anyType := Universe.Lookup("any").Type().Underlying()
   611  	comparableType := Universe.Lookup("comparable").Type()
   612  
   613  	if !Comparable(anyType) {
   614  		t.Error("any is not a comparable type")
   615  	}
   616  	if !Comparable(comparableType) {
   617  		t.Error("comparable is not a comparable type")
   618  	}
   619  
   620  	if Implements(anyType, comparableType.Underlying().(*Interface)) {
   621  		t.Error("any implements comparable")
   622  	}
   623  	if !Implements(comparableType, anyType.(*Interface)) {
   624  		t.Error("comparable does not implement any")
   625  	}
   626  
   627  	if AssignableTo(anyType, comparableType) {
   628  		t.Error("any assignable to comparable")
   629  	}
   630  	if !AssignableTo(comparableType, anyType) {
   631  		t.Error("comparable not assignable to any")
   632  	}
   633  }
   634  
   635  func TestIssue55030(t *testing.T) {
   636  	// makeSig makes the signature func(typ...)
   637  	makeSig := func(typ Type) {
   638  		par := NewVar(nopos, nil, "", typ)
   639  		params := NewTuple(par)
   640  		NewSignatureType(nil, nil, nil, params, nil, true)
   641  	}
   642  
   643  	// makeSig must not panic for the following (example) types:
   644  	// []int
   645  	makeSig(NewSlice(Typ[Int]))
   646  
   647  	// string
   648  	makeSig(Typ[String])
   649  
   650  	// P where P's core type is string
   651  	{
   652  		P := NewTypeName(nopos, nil, "P", nil) // [P string]
   653  		makeSig(NewTypeParam(P, NewInterfaceType(nil, []Type{Typ[String]})))
   654  	}
   655  
   656  	// P where P's core type is an (unnamed) slice
   657  	{
   658  		P := NewTypeName(nopos, nil, "P", nil) // [P []int]
   659  		makeSig(NewTypeParam(P, NewInterfaceType(nil, []Type{NewSlice(Typ[Int])})))
   660  	}
   661  
   662  	// P where P's core type is bytestring (i.e., string or []byte)
   663  	{
   664  		t1 := NewTerm(true, Typ[String])          // ~string
   665  		t2 := NewTerm(false, NewSlice(Typ[Byte])) // []byte
   666  		u := NewUnion([]*Term{t1, t2})            // ~string | []byte
   667  		P := NewTypeName(nopos, nil, "P", nil)    // [P ~string | []byte]
   668  		makeSig(NewTypeParam(P, NewInterfaceType(nil, []Type{u})))
   669  	}
   670  }
   671  
   672  func TestIssue51093(t *testing.T) {
   673  	// Each test stands for a conversion of the form P(val)
   674  	// where P is a type parameter with typ as constraint.
   675  	// The test ensures that P(val) has the correct type P
   676  	// and is not a constant.
   677  	var tests = []struct {
   678  		typ string
   679  		val string
   680  	}{
   681  		{"bool", "false"},
   682  		{"int", "-1"},
   683  		{"uint", "1.0"},
   684  		{"rune", "'a'"},
   685  		{"float64", "3.5"},
   686  		{"complex64", "1.25"},
   687  		{"string", "\"foo\""},
   688  
   689  		// some more complex constraints
   690  		{"~byte", "1"},
   691  		{"~int | ~float64 | complex128", "1"},
   692  		{"~uint64 | ~rune", "'X'"},
   693  	}
   694  
   695  	for _, test := range tests {
   696  		src := fmt.Sprintf("package p; func _[P %s]() { _ = P(%s) }", test.typ, test.val)
   697  		types := make(map[ast.Expr]TypeAndValue)
   698  		mustTypecheck(src, nil, &Info{Types: types})
   699  
   700  		var n int
   701  		for x, tv := range types {
   702  			if x, _ := x.(*ast.CallExpr); x != nil {
   703  				// there must be exactly one CallExpr which is the P(val) conversion
   704  				n++
   705  				tpar, _ := tv.Type.(*TypeParam)
   706  				if tpar == nil {
   707  					t.Fatalf("%s: got type %s, want type parameter", ExprString(x), tv.Type)
   708  				}
   709  				if name := tpar.Obj().Name(); name != "P" {
   710  					t.Fatalf("%s: got type parameter name %s, want P", ExprString(x), name)
   711  				}
   712  				// P(val) must not be constant
   713  				if tv.Value != nil {
   714  					t.Errorf("%s: got constant value %s (%s), want no constant", ExprString(x), tv.Value, tv.Value.String())
   715  				}
   716  			}
   717  		}
   718  
   719  		if n != 1 {
   720  			t.Fatalf("%s: got %d CallExpr nodes; want 1", src, 1)
   721  		}
   722  	}
   723  }
   724  
   725  func TestIssue54258(t *testing.T) {
   726  
   727  	tests := []struct{ main, b, want string }{
   728  		{ //---------------------------------------------------------------
   729  			`package main
   730  import "b"
   731  type I0 interface {
   732  	M0(w struct{ f string })
   733  }
   734  var _ I0 = b.S{}
   735  `,
   736  			`package b
   737  type S struct{}
   738  func (S) M0(struct{ f string }) {}
   739  `,
   740  			`6:12: cannot use b[.]S{} [(]value of type b[.]S[)] as I0 value in variable declaration: b[.]S does not implement I0 [(]wrong type for method M0[)]
   741  .*have M0[(]struct{f string /[*] package b [*]/ }[)]
   742  .*want M0[(]struct{f string /[*] package main [*]/ }[)]`},
   743  
   744  		{ //---------------------------------------------------------------
   745  			`package main
   746  import "b"
   747  type I1 interface {
   748  	M1(struct{ string })
   749  }
   750  var _ I1 = b.S{}
   751  `,
   752  			`package b
   753  type S struct{}
   754  func (S) M1(struct{ string }) {}
   755  `,
   756  			`6:12: cannot use b[.]S{} [(]value of type b[.]S[)] as I1 value in variable declaration: b[.]S does not implement I1 [(]wrong type for method M1[)]
   757  .*have M1[(]struct{string /[*] package b [*]/ }[)]
   758  .*want M1[(]struct{string /[*] package main [*]/ }[)]`},
   759  
   760  		{ //---------------------------------------------------------------
   761  			`package main
   762  import "b"
   763  type I2 interface {
   764  	M2(y struct{ f struct{ f string } })
   765  }
   766  var _ I2 = b.S{}
   767  `,
   768  			`package b
   769  type S struct{}
   770  func (S) M2(struct{ f struct{ f string } }) {}
   771  `,
   772  			`6:12: cannot use b[.]S{} [(]value of type b[.]S[)] as I2 value in variable declaration: b[.]S does not implement I2 [(]wrong type for method M2[)]
   773  .*have M2[(]struct{f struct{f string} /[*] package b [*]/ }[)]
   774  .*want M2[(]struct{f struct{f string} /[*] package main [*]/ }[)]`},
   775  
   776  		{ //---------------------------------------------------------------
   777  			`package main
   778  import "b"
   779  type I3 interface {
   780  	M3(z struct{ F struct{ f string } })
   781  }
   782  var _ I3 = b.S{}
   783  `,
   784  			`package b
   785  type S struct{}
   786  func (S) M3(struct{ F struct{ f string } }) {}
   787  `,
   788  			`6:12: cannot use b[.]S{} [(]value of type b[.]S[)] as I3 value in variable declaration: b[.]S does not implement I3 [(]wrong type for method M3[)]
   789  .*have M3[(]struct{F struct{f string /[*] package b [*]/ }}[)]
   790  .*want M3[(]struct{F struct{f string /[*] package main [*]/ }}[)]`},
   791  
   792  		{ //---------------------------------------------------------------
   793  			`package main
   794  import "b"
   795  type I4 interface {
   796  	M4(_ struct { *string })
   797  }
   798  var _ I4 = b.S{}
   799  `,
   800  			`package b
   801  type S struct{}
   802  func (S) M4(struct { *string }) {}
   803  `,
   804  			`6:12: cannot use b[.]S{} [(]value of type b[.]S[)] as I4 value in variable declaration: b[.]S does not implement I4 [(]wrong type for method M4[)]
   805  .*have M4[(]struct{[*]string /[*] package b [*]/ }[)]
   806  .*want M4[(]struct{[*]string /[*] package main [*]/ }[)]`},
   807  
   808  		{ //---------------------------------------------------------------
   809  			`package main
   810  import "b"
   811  type t struct{ A int }
   812  type I5 interface {
   813  	M5(_ struct {b.S;t})
   814  }
   815  var _ I5 = b.S{}
   816  `,
   817  			`package b
   818  type S struct{}
   819  type t struct{ A int }
   820  func (S) M5(struct {S;t}) {}
   821  `,
   822  			`7:12: cannot use b[.]S{} [(]value of type b[.]S[)] as I5 value in variable declaration: b[.]S does not implement I5 [(]wrong type for method M5[)]
   823  .*have M5[(]struct{b[.]S; b[.]t}[)]
   824  .*want M5[(]struct{b[.]S; t}[)]`},
   825  	}
   826  
   827  	fset := token.NewFileSet()
   828  	test := func(main, b, want string) {
   829  		re := regexp.MustCompile(want)
   830  		bpkg := mustTypecheck(b, nil, nil)
   831  		mast := mustParse(fset, main)
   832  		conf := Config{Importer: importHelper{pkg: bpkg}}
   833  		_, err := conf.Check(mast.Name.Name, fset, []*ast.File{mast}, nil)
   834  		if err == nil {
   835  			t.Error("Expected failure, but it did not")
   836  		} else if got := err.Error(); !re.MatchString(got) {
   837  			t.Errorf("Wanted match for\n\t%s\n but got\n\t%s", want, got)
   838  		} else if testing.Verbose() {
   839  			t.Logf("Saw expected\n\t%s", err.Error())
   840  		}
   841  	}
   842  	for _, t := range tests {
   843  		test(t.main, t.b, t.want)
   844  	}
   845  }
   846  
   847  func TestIssue59944(t *testing.T) {
   848  	testenv.MustHaveCGO(t)
   849  
   850  	// The typechecker should resolve methods declared on aliases of cgo types.
   851  	const src = `
   852  package p
   853  
   854  /*
   855  struct layout {
   856  	int field;
   857  };
   858  */
   859  import "C"
   860  
   861  type Layout = C.struct_layout
   862  
   863  func (l *Layout) Binding() {}
   864  
   865  func _() {
   866  	_ = (*Layout).Binding
   867  }
   868  `
   869  
   870  	// code generated by cmd/cgo for the above source.
   871  	const cgoTypes = `
   872  // Code generated by cmd/cgo; DO NOT EDIT.
   873  
   874  package p
   875  
   876  import "unsafe"
   877  
   878  import "syscall"
   879  
   880  import _cgopackage "runtime/cgo"
   881  
   882  type _ _cgopackage.Incomplete
   883  var _ syscall.Errno
   884  func _Cgo_ptr(ptr unsafe.Pointer) unsafe.Pointer { return ptr }
   885  
   886  //go:linkname _Cgo_always_false runtime.cgoAlwaysFalse
   887  var _Cgo_always_false bool
   888  //go:linkname _Cgo_use runtime.cgoUse
   889  func _Cgo_use(interface{})
   890  type _Ctype_int int32
   891  
   892  type _Ctype_struct_layout struct {
   893  	field _Ctype_int
   894  }
   895  
   896  type _Ctype_void [0]byte
   897  
   898  //go:linkname _cgo_runtime_cgocall runtime.cgocall
   899  func _cgo_runtime_cgocall(unsafe.Pointer, uintptr) int32
   900  
   901  //go:linkname _cgoCheckPointer runtime.cgoCheckPointer
   902  func _cgoCheckPointer(interface{}, interface{})
   903  
   904  //go:linkname _cgoCheckResult runtime.cgoCheckResult
   905  func _cgoCheckResult(interface{})
   906  `
   907  	testFiles(t, []string{"p.go", "_cgo_gotypes.go"}, [][]byte{[]byte(src), []byte(cgoTypes)}, false, func(cfg *Config) {
   908  		*boolFieldAddr(cfg, "go115UsesCgo") = true
   909  	})
   910  }
   911  
   912  func TestIssue61931(t *testing.T) {
   913  	const src = `
   914  package p
   915  
   916  func A(func(any), ...any) {}
   917  func B[T any](T)          {}
   918  
   919  func _() {
   920  	A(B, nil // syntax error: missing ',' before newline in argument list
   921  }
   922  `
   923  	fset := token.NewFileSet()
   924  	f, err := parser.ParseFile(fset, pkgName(src), src, 0)
   925  	if err == nil {
   926  		t.Fatal("expected syntax error")
   927  	}
   928  
   929  	var conf Config
   930  	conf.Check(f.Name.Name, fset, []*ast.File{f}, nil) // must not panic
   931  }
   932  
   933  func TestIssue61938(t *testing.T) {
   934  	const src = `
   935  package p
   936  
   937  func f[T any]() {}
   938  func _()        { f() }
   939  `
   940  	// no error handler provided (this issue)
   941  	var conf Config
   942  	typecheck(src, &conf, nil) // must not panic
   943  
   944  	// with error handler (sanity check)
   945  	conf.Error = func(error) {}
   946  	typecheck(src, &conf, nil) // must not panic
   947  }
   948  
   949  func TestIssue63260(t *testing.T) {
   950  	const src = `
   951  package p
   952  
   953  func _() {
   954          use(f[*string])
   955  }
   956  
   957  func use(func()) {}
   958  
   959  func f[I *T, T any]() {
   960          var v T
   961          _ = v
   962  }`
   963  
   964  	info := Info{
   965  		Defs: make(map[*ast.Ident]Object),
   966  	}
   967  	pkg := mustTypecheck(src, nil, &info)
   968  
   969  	// get type parameter T in signature of f
   970  	T := pkg.Scope().Lookup("f").Type().(*Signature).TypeParams().At(1)
   971  	if T.Obj().Name() != "T" {
   972  		t.Fatalf("got type parameter %s, want T", T)
   973  	}
   974  
   975  	// get type of variable v in body of f
   976  	var v Object
   977  	for name, obj := range info.Defs {
   978  		if name.Name == "v" {
   979  			v = obj
   980  			break
   981  		}
   982  	}
   983  	if v == nil {
   984  		t.Fatal("variable v not found")
   985  	}
   986  
   987  	// type of v and T must be pointer-identical
   988  	if v.Type() != T {
   989  		t.Fatalf("types of v and T are not pointer-identical: %p != %p", v.Type().(*TypeParam), T)
   990  	}
   991  }
   992  
   993  func TestIssue44410(t *testing.T) {
   994  	const src = `
   995  package p
   996  
   997  type A = []int
   998  type S struct{ A }
   999  `
  1000  
  1001  	t.Setenv("GODEBUG", "gotypesalias=1")
  1002  	pkg := mustTypecheck(src, nil, nil)
  1003  
  1004  	S := pkg.Scope().Lookup("S")
  1005  	if S == nil {
  1006  		t.Fatal("object S not found")
  1007  	}
  1008  
  1009  	got := S.String()
  1010  	const want = "type p.S struct{p.A}"
  1011  	if got != want {
  1012  		t.Fatalf("got %q; want %q", got, want)
  1013  	}
  1014  }
  1015  
  1016  func TestIssue59831(t *testing.T) {
  1017  	// Package a exports a type S with an unexported method m;
  1018  	// the tests check the error messages when m is not found.
  1019  	const asrc = `package a; type S struct{}; func (S) m() {}`
  1020  	apkg := mustTypecheck(asrc, nil, nil)
  1021  
  1022  	// Package b exports a type S with an exported method m;
  1023  	// the tests check the error messages when M is not found.
  1024  	const bsrc = `package b; type S struct{}; func (S) M() {}`
  1025  	bpkg := mustTypecheck(bsrc, nil, nil)
  1026  
  1027  	tests := []struct {
  1028  		imported *Package
  1029  		src, err string
  1030  	}{
  1031  		// tests importing a (or nothing)
  1032  		{apkg, `package a1; import "a"; var _ interface { M() } = a.S{}`,
  1033  			"a.S does not implement interface{M()} (missing method M) have m() want M()"},
  1034  
  1035  		{apkg, `package a2; import "a"; var _ interface { m() } = a.S{}`,
  1036  			"a.S does not implement interface{m()} (unexported method m)"}, // test for issue
  1037  
  1038  		{nil, `package a3; type S struct{}; func (S) m(); var _ interface { M() } = S{}`,
  1039  			"S does not implement interface{M()} (missing method M) have m() want M()"},
  1040  
  1041  		{nil, `package a4; type S struct{}; func (S) m(); var _ interface { m() } = S{}`,
  1042  			""}, // no error expected
  1043  
  1044  		{nil, `package a5; type S struct{}; func (S) m(); var _ interface { n() } = S{}`,
  1045  			"S does not implement interface{n()} (missing method n)"},
  1046  
  1047  		// tests importing b (or nothing)
  1048  		{bpkg, `package b1; import "b"; var _ interface { m() } = b.S{}`,
  1049  			"b.S does not implement interface{m()} (missing method m) have M() want m()"},
  1050  
  1051  		{bpkg, `package b2; import "b"; var _ interface { M() } = b.S{}`,
  1052  			""}, // no error expected
  1053  
  1054  		{nil, `package b3; type S struct{}; func (S) M(); var _ interface { M() } = S{}`,
  1055  			""}, // no error expected
  1056  
  1057  		{nil, `package b4; type S struct{}; func (S) M(); var _ interface { m() } = S{}`,
  1058  			"S does not implement interface{m()} (missing method m) have M() want m()"},
  1059  
  1060  		{nil, `package b5; type S struct{}; func (S) M(); var _ interface { n() } = S{}`,
  1061  			"S does not implement interface{n()} (missing method n)"},
  1062  	}
  1063  
  1064  	for _, test := range tests {
  1065  		// typecheck test source
  1066  		conf := Config{Importer: importHelper{pkg: test.imported}}
  1067  		pkg, err := typecheck(test.src, &conf, nil)
  1068  		if err == nil {
  1069  			if test.err != "" {
  1070  				t.Errorf("package %s: got no error, want %q", pkg.Name(), test.err)
  1071  			}
  1072  			continue
  1073  		}
  1074  		if test.err == "" {
  1075  			t.Errorf("package %s: got %q, want not error", pkg.Name(), err.Error())
  1076  		}
  1077  
  1078  		// flatten reported error message
  1079  		errmsg := strings.ReplaceAll(err.Error(), "\n", " ")
  1080  		errmsg = strings.ReplaceAll(errmsg, "\t", "")
  1081  
  1082  		// verify error message
  1083  		if !strings.Contains(errmsg, test.err) {
  1084  			t.Errorf("package %s: got %q, want %q", pkg.Name(), errmsg, test.err)
  1085  		}
  1086  	}
  1087  }
  1088  
  1089  func TestIssue64759(t *testing.T) {
  1090  	const src = `
  1091  //go:build go1.18
  1092  package p
  1093  
  1094  func f[S ~[]E, E any](S) {}
  1095  
  1096  func _() {
  1097  	f([]string{})
  1098  }
  1099  `
  1100  	// Per the go:build directive, the source must typecheck
  1101  	// even though the (module) Go version is set to go1.17.
  1102  	conf := Config{GoVersion: "go1.17"}
  1103  	mustTypecheck(src, &conf, nil)
  1104  }
  1105  
  1106  func TestIssue68334(t *testing.T) {
  1107  	const src = `
  1108  package p
  1109  
  1110  func f(x int) {
  1111  	for i, j := range x {
  1112  		_, _ = i, j
  1113  	}
  1114  	var a, b int
  1115  	for a, b = range x {
  1116  		_, _ = a, b
  1117  	}
  1118  }
  1119  `
  1120  
  1121  	got := ""
  1122  	conf := Config{
  1123  		GoVersion: "go1.21",                                      // #68334 requires GoVersion <= 1.21
  1124  		Error:     func(err error) { got += err.Error() + "\n" }, // #68334 requires Error != nil
  1125  	}
  1126  	typecheck(src, &conf, nil) // do not crash
  1127  
  1128  	want := "p:5:20: cannot range over x (variable of type int): requires go1.22 or later\n" +
  1129  		"p:9:19: cannot range over x (variable of type int): requires go1.22 or later\n"
  1130  	if got != want {
  1131  		t.Errorf("got: %s want: %s", got, want)
  1132  	}
  1133  }
  1134  
  1135  func TestIssue68877(t *testing.T) {
  1136  	const src = `
  1137  package p
  1138  
  1139  type (
  1140  	S struct{}
  1141  	A = S
  1142  	T A
  1143  )`
  1144  
  1145  	t.Setenv("GODEBUG", "gotypesalias=1")
  1146  	pkg := mustTypecheck(src, nil, nil)
  1147  	T := pkg.Scope().Lookup("T").(*TypeName)
  1148  	got := T.String() // this must not panic (was issue)
  1149  	const want = "type p.T struct{}"
  1150  	if got != want {
  1151  		t.Errorf("got %s, want %s", got, want)
  1152  	}
  1153  }
  1154  

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