diff options
author | Robert Griesemer <gri@golang.org> | 2023-10-02 15:47:08 -0700 |
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committer | Gopher Robot <gobot@golang.org> | 2023-10-03 21:21:52 +0000 |
commit | 51cb717d272545c2d4160f76a9f13741aa1e7abd (patch) | |
tree | ac8d453f9be40c6070741e9fe2ddfb62e7bd7227 | |
parent | dc523c8ddf5b0ce985ea90c65cbaa097c9e3ee09 (diff) | |
download | go-51cb717d272545c2d4160f76a9f13741aa1e7abd.tar.gz go-51cb717d272545c2d4160f76a9f13741aa1e7abd.zip |
go/types, types2: don't implicitly modify an argument function's type
See the comment in the (very small) fix for a detailed description.
Use the opportunity to introduce a generic clone function which may
be useful elsewhere.
Fixes #63260.
Change-Id: Ic63c6b8bc443011b1a201908254f7d062e1aec71
Reviewed-on: https://go-review.googlesource.com/c/go/+/532157
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
-rw-r--r-- | src/cmd/compile/internal/types2/call.go | 7 | ||||
-rw-r--r-- | src/cmd/compile/internal/types2/issues_test.go | 44 | ||||
-rw-r--r-- | src/cmd/compile/internal/types2/predicates.go | 6 | ||||
-rw-r--r-- | src/go/types/call.go | 7 | ||||
-rw-r--r-- | src/go/types/issues_test.go | 44 | ||||
-rw-r--r-- | src/go/types/predicates.go | 6 |
6 files changed, 114 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/types2/call.go b/src/cmd/compile/internal/types2/call.go index 7b0fa10f32..439f515265 100644 --- a/src/cmd/compile/internal/types2/call.go +++ b/src/cmd/compile/internal/types2/call.go @@ -569,6 +569,13 @@ func (check *Checker) arguments(call *syntax.CallExpr, sig *Signature, targs []T for i, arg := range args { // generic arguments cannot have a defined (*Named) type - no need for underlying type below if asig, _ := arg.typ.(*Signature); asig != nil && asig.TypeParams().Len() > 0 { + // The argument type is a generic function signature. This type is + // pointer-identical with (it's copied from) the type of the generic + // function argument and thus the function object. + // Before we change the type (type parameter renaming, below), make + // a clone of it as otherwise we implicitly modify the object's type + // (go.dev/issues/63260). + asig = clone(asig) // Rename type parameters for cases like f(g, g); this gives each // generic function argument a unique type identity (go.dev/issues/59956). // TODO(gri) Consider only doing this if a function argument appears diff --git a/src/cmd/compile/internal/types2/issues_test.go b/src/cmd/compile/internal/types2/issues_test.go index bcebc2f2c0..32671403c2 100644 --- a/src/cmd/compile/internal/types2/issues_test.go +++ b/src/cmd/compile/internal/types2/issues_test.go @@ -936,3 +936,47 @@ func _() { f() } conf.Error = func(error) {} typecheck(src, &conf, nil) // must not panic } + +func TestIssue63260(t *testing.T) { + const src = ` +package p + +func _() { + use(f[*string]) +} + +func use(func()) {} + +func f[I *T, T any]() { + var v T + _ = v +}` + + info := Info{ + Defs: make(map[*syntax.Name]Object), + } + pkg := mustTypecheck(src, nil, &info) + + // get type parameter T in signature of f + T := pkg.Scope().Lookup("f").Type().(*Signature).TypeParams().At(1) + if T.Obj().Name() != "T" { + t.Fatalf("got type parameter %s, want T", T) + } + + // get type of variable v in body of f + var v Object + for name, obj := range info.Defs { + if name.Value == "v" { + v = obj + break + } + } + if v == nil { + t.Fatal("variable v not found") + } + + // type of v and T must be pointer-identical + if v.Type() != T { + t.Fatalf("types of v and T are not pointer-identical: %p != %p", v.Type().(*TypeParam), T) + } +} diff --git a/src/cmd/compile/internal/types2/predicates.go b/src/cmd/compile/internal/types2/predicates.go index c48f926bf8..11f543f475 100644 --- a/src/cmd/compile/internal/types2/predicates.go +++ b/src/cmd/compile/internal/types2/predicates.go @@ -533,3 +533,9 @@ func maxType(x, y Type) Type { } return nil } + +// clone makes a "flat copy" of *p and returns a pointer to the copy. +func clone[P *T, T any](p P) P { + c := *p + return &c +} diff --git a/src/go/types/call.go b/src/go/types/call.go index 18c40629a5..12f547ea38 100644 --- a/src/go/types/call.go +++ b/src/go/types/call.go @@ -571,6 +571,13 @@ func (check *Checker) arguments(call *ast.CallExpr, sig *Signature, targs []Type for i, arg := range args { // generic arguments cannot have a defined (*Named) type - no need for underlying type below if asig, _ := arg.typ.(*Signature); asig != nil && asig.TypeParams().Len() > 0 { + // The argument type is a generic function signature. This type is + // pointer-identical with (it's copied from) the type of the generic + // function argument and thus the function object. + // Before we change the type (type parameter renaming, below), make + // a clone of it as otherwise we implicitly modify the object's type + // (go.dev/issues/63260). + asig = clone(asig) // Rename type parameters for cases like f(g, g); this gives each // generic function argument a unique type identity (go.dev/issues/59956). // TODO(gri) Consider only doing this if a function argument appears diff --git a/src/go/types/issues_test.go b/src/go/types/issues_test.go index bdc1a388d8..5530fceef6 100644 --- a/src/go/types/issues_test.go +++ b/src/go/types/issues_test.go @@ -946,3 +946,47 @@ func _() { f() } conf.Error = func(error) {} typecheck(src, &conf, nil) // must not panic } + +func TestIssue63260(t *testing.T) { + const src = ` +package p + +func _() { + use(f[*string]) +} + +func use(func()) {} + +func f[I *T, T any]() { + var v T + _ = v +}` + + info := Info{ + Defs: make(map[*ast.Ident]Object), + } + pkg := mustTypecheck(src, nil, &info) + + // get type parameter T in signature of f + T := pkg.Scope().Lookup("f").Type().(*Signature).TypeParams().At(1) + if T.Obj().Name() != "T" { + t.Fatalf("got type parameter %s, want T", T) + } + + // get type of variable v in body of f + var v Object + for name, obj := range info.Defs { + if name.Name == "v" { + v = obj + break + } + } + if v == nil { + t.Fatal("variable v not found") + } + + // type of v and T must be pointer-identical + if v.Type() != T { + t.Fatalf("types of v and T are not pointer-identical: %p != %p", v.Type().(*TypeParam), T) + } +} diff --git a/src/go/types/predicates.go b/src/go/types/predicates.go index 331a8f69aa..01804c69c5 100644 --- a/src/go/types/predicates.go +++ b/src/go/types/predicates.go @@ -535,3 +535,9 @@ func maxType(x, y Type) Type { } return nil } + +// clone makes a "flat copy" of *p and returns a pointer to the copy. +func clone[P *T, T any](p P) P { + c := *p + return &c +} |