gc: initial BOM is legal.

Fixes #4040.

R=rsc
CC=golang-dev
https://golang.org/cl/6497098

1 files changed, 26 insertions, 0 deletions

diff --git a/test/bom.go b/test/bom.go
new file mode 100644
index 0000000000..37f73bc5d2
--- /dev/null
+++ b/test/bom.go
@@ -0,0 +1,26 @@
+// runoutput
+
+// 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.
+
+// Test source file beginning with a byte order mark.
+
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func main() {
+	prog = strings.Replace(prog, "BOM", "\uFEFF", -1)
+	fmt.Print(prog)
+}
+
+var prog = `BOM
+package main
+
+func main() {
+}
+`