put toplevel & check back and add test

R=ken
OCL=17307
CL=17307

src/cmd/gc/go.y

@@ -754,6 +754,8 @@ uexpr:
 	}
 |	'&' uexpr
 	{
+		if($2->op == OCONV && !func)
+			yyerror("& of composite literal at top level");
 		$$ = nod(OADDR, $2, N);
 	}
 |	'+' uexpr
@@ -1179,11 +1181,13 @@ xfndcl:
 	{
 		maxarg = 0;
 		stksize = 0;
+		func++;
 	} fndcl fnbody
 	{
 		$$ = $3;
 		$$->nbody = $4;
 		funcbody($$);
+		func--;
 	}
 
 fndcl:

test/addr.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
+
+var a = &[]int{1,2};	// ERROR "composite"