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go/test/typeparam/eface.go
Keith Randall 6a35e07512 cmd/compile: fix stenciling of conversions between interfaces
Conversions need to allow nil through.
We do that using a CONVIFACE instead of a DOTTYPE.

Also reorganize how nonempty interfaces are handled.
For nonempty to empty, a simple CONVIFACE suffices.
For nonempty to nonempty, we need to call the runtime to get the
new itab. Use the entry from the dictionary to identify the
target interface type (if parameterized).

Fixes #47925

Change-Id: I4ffeed964318bb3e270b06f558e6ab9c5bfc7188
Reviewed-on: https://go-review.googlesource.com/c/go/+/344830
Trust: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
2021-08-27 16:41:29 +00:00

68 lines
1.1 KiB
Go

// run -gcflags=-G=3
// 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.
// Make sure we handle instantiated empty interfaces.
package main
type E[T any] interface {
}
//go:noinline
func f[T any](x E[T]) interface{} {
return x
}
//go:noinline
func g[T any](x interface{}) E[T] {
return x
}
type I[T any] interface {
foo()
}
type myint int
func (x myint) foo() {}
//go:noinline
func h[T any](x I[T]) interface{ foo() } {
return x
}
//go:noinline
func i[T any](x interface{ foo() }) I[T] {
return x
}
func main() {
if f[int](1) != 1 {
println("test 1 failed")
}
if f[int](2) != (interface{})(2) {
println("test 2 failed")
}
if g[int](3) != 3 {
println("test 3 failed")
}
if g[int](4) != (E[int])(4) {
println("test 4 failed")
}
if h[int](myint(5)) != myint(5) {
println("test 5 failed")
}
if h[int](myint(6)) != interface{ foo() }(myint(6)) {
println("test 6 failed")
}
if i[int](myint(7)) != myint(7) {
println("test 7 failed")
}
if i[int](myint(8)) != I[int](myint(8)) {
println("test 8 failed")
}
}