issue47708.go

     1  // run
     2  
     3  // Copyright 2021 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package main
     8  
     9  type FooType[T any] interface {
    10  	Foo(BarType[T]) string
    11  }
    12  type BarType[T any] interface {
    13  	Bar(FooType[T]) string
    14  }
    15  
    16  // For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
    17  // type Baz[T any] T
    18  // func (l Baz[T]) Foo(v BarType[T]) string {
    19  // 	return v.Bar(l)
    20  // }
    21  // type Bob[T any] T
    22  // func (l Bob[T]) Bar(v FooType[T]) string {
    23  // 	if v,ok := v.(Baz[T]);ok{
    24  // 		return fmt.Sprintf("%v%v",v,l)
    25  // 	}
    26  // 	return ""
    27  // }
    28  
    29  func main() {
    30  	// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
    31  	// var baz Baz[int] = 123
    32  	// var bob Bob[int] = 456
    33  	//
    34  	// if got, want := baz.Foo(bob), "123456"; got != want {
    35  	// 	panic(fmt.Sprintf("got %s want %s", got, want))
    36  	// }
    37  }
    38
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