cmd/compile: fix error when typeswitching on untyped
Fixes #20185
Fixes #19977
Change-Id: I8434713d20616ff0c0bc8f33f017e2548a5cccfa
Reviewed-on: https://go-review.googlesource.com/42210
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/test/fixedbugs/issue19977.go b/test/fixedbugs/issue19977.go
new file mode 100644
index 0000000..3db1dfd
--- /dev/null
+++ b/test/fixedbugs/issue19977.go
@@ -0,0 +1,16 @@
+// errorcheck
+
+// 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.
+
+// Issue 19977: multiple error messages when type switching on an undefined
+
+package foo
+
+func Foo() {
+ switch x := a.(type) { // ERROR "undefined: a"
+ default:
+ _ = x
+ }
+}
