wrong type used for dynamic type test

R=r
DELTA=40  (40 added, 0 deleted, 0 changed)
OCL=28308
CL=28311

test/bugs/bug148.go

@@ -0,0 +1,39 @@
+// $G $D/$F.go && $L $F.$A && ! ./$A.out || echo BUG: should crash
+
+// Copyright 2009 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
+
+type T struct {a, b int};
+
+func f(x interface{}) interface{} {
+	type T struct {a, b int};
+
+	if x == nil {
+		return T{2, 3};
+	}
+
+	t := x.(T);
+	println(t.a, t.b);
+	return x;
+}
+
+func main() {
+	inner_T := f(nil);
+	f(inner_T);
+
+	outer_T := T{5, 7};
+	f(outer_T);
+}
+
+/*
+This prints:
+
+2 3
+5 7
+
+but it should crash: The type assertion on line 14 should fail
+for the 2nd call to f with outer_T.
+*/

test/golden.out

@@ -96,6 +96,11 @@ bugs/bug140.go:6: syntax error near L1
 bugs/bug140.go:7: syntax error near L2
 BUG should compile
 
+=========== bugs/bug148.go
+2 3
+5 7
+BUG: should crash
+
 =========== fixedbugs/bug016.go
 fixedbugs/bug016.go:7: constant -3 overflows uint