A test for an interface which uses a forward declared type

which turns out to be invalid.

R=rsc
DELTA=15  (15 added, 0 deleted, 0 changed)
OCL=33691
CL=33693

test/bugs/bug195.go

+// errchk $G $D/$F.go
+
+// 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 I1 interface { I2 }	// ERROR "interface"
+type I2 int
+
+type I3 interface { int }	// ERROR "interface"

test/golden.out

@@ -177,3 +177,6 @@ errchk: bugs/bug193.go:14: missing expected error: 'shift'
 =========== bugs/bug194.go
 BUG should compile and run
 $RUNFILE: line 1: PID Segmentation fault      (core dumped) $G $D/$F.go
+
+=========== bugs/bug195.go
+bugs/bug195.go:9: BUG: errchk: compiler crashed