test: add regress test for #53419

This currently works with GOEXPERIMENT=unified. Add a regress test to
make sure it stays that way.

Updates #53419.

Change-Id: I2ea1f9039c59807fbd497d69a0420771f8d6d035
Reviewed-on: https://go-review.googlesource.com/c/go/+/413014
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/test/typeparam/issue53419.go b/test/typeparam/issue53419.go
new file mode 100644
index 0000000000..62a226ff9f
--- /dev/null
+++ b/test/typeparam/issue53419.go
@@ -0,0 +1,28 @@
+// run
+
+// Copyright 2022 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 T1 struct{}
+type T2 struct{}
+type Both struct {
+	T1
+	T2
+}
+
+func (T1) m()   { panic("FAIL") }
+func (T2) m()   { panic("FAIL") }
+func (Both) m() {}
+
+func f[T interface{ m() }](c T) {
+	c.m()
+}
+
+func main() {
+	var b Both
+	b.m()
+	f(b)
+}