From ffa6b383f5ac5ab317701a4cccea3aa5b585f477 Mon Sep 17 00:00:00 2001
From: Maxim Pimenov <mpimenov@google.com>
Date: Mon, 28 Nov 2011 11:52:16 -0500
Subject: [PATCH] gc: fix copying of types reset xmethod during copytype

Fixes #2497

R=rsc, dvyukov
CC=golang-dev
https://golang.org/cl/5441045
---
 src/cmd/gc/typecheck.c   |  1 +
 test/fixedbugs/bug378.go | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 test/fixedbugs/bug378.go

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 5b667553fa2..2ec3c729714 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -2530,6 +2530,7 @@ copytype(Node *n, Type *t)
 	t->vargen = n->vargen;
 	t->siggen = 0;
 	t->method = nil;
+	t->xmethod = nil;
 	t->nod = N;
 	t->printed = 0;
 	t->deferwidth = 0;
diff --git a/test/fixedbugs/bug378.go b/test/fixedbugs/bug378.go
new file mode 100644
index 00000000000..b393b3dc1e9
--- /dev/null
+++ b/test/fixedbugs/bug378.go
@@ -0,0 +1,19 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out || echo BUG: bug378
+
+// Copyright 2011 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.
+
+// Issue 2497
+
+package main
+
+type Header struct{}
+func (h Header) Method() {}
+
+var _ interface{} = Header{}
+
+func main() {
+  	type X Header
+  	var _ interface{} = X{}
+}