cmd/compile: add regress test for #20682

Minimal reconstruction of reported failure case.

Manually verified that test fails with CL 45911 reverted.

Change-Id: Ia5d11500d91b46ba1eb5d841db3987edb9136c39
Reviewed-on: https://go-review.googlesource.com/45970
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>

4 files changed, 44 insertions, 0 deletions

diff --git a/test/fixedbugs/issue20682.dir/p.go b/test/fixedbugs/issue20682.dir/p.go
new file mode 100644
index 0000000000..fc37136d90
--- /dev/null
+++ b/test/fixedbugs/issue20682.dir/p.go
@@ -0,0 +1,13 @@
+// Copyright 2017 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 p
+
+import "strings"
+
+type T struct{}
+
+func (T) M() {
+	strings.HasPrefix("", "")
+}
diff --git a/test/fixedbugs/issue20682.dir/q.go b/test/fixedbugs/issue20682.dir/q.go
new file mode 100644
index 0000000000..9554569de0
--- /dev/null
+++ b/test/fixedbugs/issue20682.dir/q.go
@@ -0,0 +1,13 @@
+// Copyright 2017 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 q
+
+import "./p"
+
+type T struct{}
+
+func (T) M() interface{} {
+	return &p.T{}
+}
diff --git a/test/fixedbugs/issue20682.dir/r.go b/test/fixedbugs/issue20682.dir/r.go
new file mode 100644
index 0000000000..73dfe1b3af
--- /dev/null
+++ b/test/fixedbugs/issue20682.dir/r.go
@@ -0,0 +1,11 @@
+// Copyright 2017 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 r
+
+import "./q"
+
+type T struct {
+	q.T
+}
diff --git a/test/fixedbugs/issue20682.go b/test/fixedbugs/issue20682.go
new file mode 100644
index 0000000000..8000a5224f
--- /dev/null
+++ b/test/fixedbugs/issue20682.go
@@ -0,0 +1,7 @@
+// compiledir
+
+// Copyright 2017 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 ignored