code review 3259043: gc: fix method offsets of anonymous interfaces

test/fixedbugs/bug314.go

Index: test/fixedbugs/bug314.go
===================================================================
new file mode 100644
--- /dev/null
+++ b/test/fixedbugs/bug314.go
@@ -0,0 +1,31 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out || echo BUG: bug314
+
+// Copyright 2010 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.
+
+// Used to call wrong methods; issue 1290.
+
+package main
+
+type S struct {
+}
+func (S) a() int{
+	return 0
+}
+func (S) b() int{
+	return 1
+}
+
+func main() {
+	var i interface {
+		b() int
+		a() int
+	} = S{}
+	if i.a() != 0 {
+		panic("wrong method called")
+	}
+	if i.b() != 1 {
+		panic("wrong method called")
+	}
+}