bug252: make ... vs ...T crossing an error, at least for now

R=r
CC=golang-dev
https://golang.org/cl/199066

test/fixedbugs/bug252.go

@@ -0,0 +1,15 @@
+// errchk $G $D/$F.go
+
+// Copyright 2010 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
+
+func f(args ...) {
+	g(args)	// ERROR "[.][.][.] mismatch"
+}
+
+func g(args ...interface{}) {
+	f(args)	// ERROR "[.][.][.] mismatch"
+}