golang issue47747 代码
文件路径：/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47747.go
/ Copyright 2021 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 p
/ For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
/ type T1[P any] P
/
/ func (T1[_]) m() {}
/
/ func _[P any](x *T1[P]) {
/ / x.m exists because x is of type *T1 where T1 is a defined type
/ / (even though under(T1) is a type parameter)
/ x.m()
/ }
func _[P interface{ m() }](x P) {
x.m()
/ (&x).m doesn't exist because &x is of type *P
/ and pointers to type parameters don't have methods
(&x).m /* ERROR type \*P is pointer to type parameter, not type parameter */ ()
}
type T2 interface{ m() }
func _(x *T2) {
/ x.m doesn't exists because x is of type *T2
/ and pointers to interfaces don't have methods
x.m /* ERROR type \*T2 is pointer to interface, not interface */()
}
/ Test case 1 from issue
type Fooer1[t any] interface {
Foo(Barer[t])
}
type Barer[t any] interface {
Bar(t)
}
/ For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
/ type Foo1[t any] t
/ type Bar[t any] t
/
/ func (l Foo1[t]) Foo(v Barer[t]) { v.Bar(t(l)) }
/ func (b *Bar[t]) Bar(l t) { *b = Bar[t](l) }
/
/ func _[t any](f Fooer1[t]) t {
/ var b Bar[t]
/ f.Foo(&b)
/ return t(b)
/ }
/ Test case 2 from issue
/ For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
/ type Fooer2[t any] interface {
/ Foo()
/ }
/
/ type Foo2[t any] t
/
/ func (f *Foo2[t]) Foo() {}
/
/ func _[t any](v t) {
/ var f = Foo2[t](v)
/ _ = Fooer2[t](&f)
/ }