Test that the compiler rejects map types which should not be

compatible.

R=rsc
CC=go-dev
http://go/go-review/1018001

test/bugs/bug212.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 I int 
+type S struct { f map[I]int }
+var v1 = S{ make(map[int]int) }		// OK--names are ignored.
+var v2 map[I]int = map[int]int{}	// OK.
+var v3 = S{ make(map[uint]int) }	// ERROR "cannot|illegal|incompatible|wrong"

test/golden.out

@@ -201,3 +201,6 @@ throw: interface conversion
 panic PC=xxx
 
 == bugs/
+
+=========== bugs/bug212.go
+BUG: errchk: command succeeded unexpectedly