| // 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 \*P has no field or method m */ () |
| } |
| |
| |
| 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 \*T2 has no field or method m */() |
| } |
| |
| // 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) |
| // } |
