diff options
Diffstat (limited to 'test/typeparam/issue47925d.go')
-rw-r--r-- | test/typeparam/issue47925d.go | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/test/typeparam/issue47925d.go b/test/typeparam/issue47925d.go new file mode 100644 index 0000000..c5647f9 --- /dev/null +++ b/test/typeparam/issue47925d.go @@ -0,0 +1,47 @@ +// run + +// 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 J[T any] interface { + foo() + bar() +} + +//go:noinline +func f[T J[T]](x T, g func(T) T) I[T] { + // contains a cast between two nonempty interfaces + // Also make sure we don't evaluate g(x) twice. + return I[T](J[T](g(x))) +} + +type S struct { + x int +} + +func (s *S) foo() {} +func (s *S) bar() {} + +var cnt int + +func inc(s *S) *S { + cnt++ + return s +} + +func main() { + i := f(&S{x: 7}, inc) + if i.(*S).x != 7 { + panic("bad") + } + if cnt != 1 { + panic("multiple calls") + } +} |