re PR c++/28710 (ICE redeclaring template as non-template)

	PR c++/28710
	* decl.c (xref_tag): Improve error message.  Return early on error.

	* g++.dg/template/redecl4.C: New test.

From-SVN: r116211

gcc/cp/ChangeLog

 2006-08-17  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
+	PR c++/28710
+	* decl.c (xref_tag): Improve error message.  Return early on error.
+
 	PR c++/28711
 	* pt.c (tsubst_copy_and_build) <case CONSTRUCTOR>: Robustify.
 

gcc/cp/decl.c

@@ -9695,7 +9695,8 @@ xref_tag (enum tag_types tag_code, tree name,
 	       && CLASSTYPE_IS_TEMPLATE (t))
 	{
 	  error ("redeclaration of %qT as a non-template", t);
-	  t = error_mark_node;
+	  error ("previous declaration %q+D", t);
+	  POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node);
 	}
 
       /* Make injected friend class visible.  */

gcc/testsuite/ChangeLog

 2006-08-17  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
+	PR c++/28710
+	* g++.dg/template/redecl4.C: New test.
+
 	PR c++/28711
 	* g++.dg/template/ctor8.C: New test.
 

gcc/testsuite/g++.dg/template/redecl4.C

+// PR c++/28710
+// { dg-do compile }
+
+template<int> union A;  // { dg-error "previous" }
+struct A;               // { dg-error "non-template" }