2022-02-28 22:32:19 +00:00
|
|
|
// run
|
2021-08-24 22:41:11 +00:00
|
|
|
|
|
|
|
|
// 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 main
|
|
|
|
|
|
|
|
|
|
type I[T any] interface {
|
|
|
|
|
foo()
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
type E[T any] interface {
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
//go:noinline
|
|
|
|
|
func f[T I[T]](x T) E[T] {
|
|
|
|
|
// contains a cast from nonempty to empty interface
|
|
|
|
|
return E[T](I[T](x))
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
type S struct {
|
|
|
|
|
x int
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
func (s *S) foo() {}
|
|
|
|
|
|
|
|
|
|
func main() {
|
|
|
|
|
i := f(&S{x: 7})
|
|
|
|
|
if i.(*S).x != 7 {
|
|
|
|
|
panic("bad")
|
|
|
|
|
}
|
|
|
|
|
}
|
