I don't know when the bug was fixed, but empirically it was.
Make sure it stays fixed by adding a test.
Fixes #7884.
LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/
93500043
--- /dev/null
+// compile
+
+// Copyright 2014 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
+
+import "fmt"
+
+func main() {
+ var ii interface{} = 5
+ zz, err := ii.(interface{})
+ fmt.Println(zz, err)
+}