re PR c++/6723 (ICE on source code successfully compiled by previous versions)

	PR c++/6723
	* pt.c (lookup_template_class): Don't build complete argument of
	BOUND_TEMPLATE_TEMPLATE_PARM if appeared as a default template
	argument.

	* g++.dg/template/ttp4.C: New test.

From-SVN: r54831

gcc/cp/ChangeLog

+2002-06-20  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>
+
+	PR c++/6723
+	* pt.c (lookup_template_class): Don't build complete argument of
+	BOUND_TEMPLATE_TEMPLATE_PARM if appeared as a default template
+	argument.
+
 2002-06-19  Akim Demaille  <akim@epita.fr>
 
 	* parse.y (TYPENAME): Rename as tTYPENAME to avoid the clash with

gcc/cp/pt.c

@@ -3967,10 +3967,16 @@ lookup_template_class (d1, arglist, in_decl, context, entering_scope, complain)
 	 The template parameter level of T and U are one level larger than 
 	 of TT.  To proper process the default argument of U, say when an 
 	 instantiation `TT<int>' is seen, we need to build the full
-	 arguments containing {int} as the innermost level.  Outer levels
-	 can be obtained from `current_template_args ()'.  */
+	 arguments containing {int} as the innermost level.  Outer levels,
+	 available when not appearing as default template argument, can be
+	 obtained from `current_template_args ()'.
 
-      if (processing_template_decl)
+	 Suppose that TT is later substituted with std::vector.  The above
+	 instantiation is `TT<int, std::allocator<T> >' with TT at
+	 level 1, and T at level 2, while the template arguments at level 1
+	 becomes {std::vector} and the inner level 2 is {int}.  */
+
+      if (current_template_parms)
 	arglist = add_to_template_args (current_template_args (), arglist);
 
       arglist2 = coerce_template_parms (parmlist, arglist, template,

gcc/testsuite/ChangeLog

+2002-06-20  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>
+
+	* g++.dg/template/ttp4.C: New test.
+
 2002-06-19  Jakub Jelinek  <jakub@redhat.com>
 
 	* g++.dg/opt/vt1.C: Fix regexp.

gcc/testsuite/g++.dg/template/ttp4.C

+// { dg-do compile }
+// Origin: Ewgenij Gawrilow <gawrilow@math.tu-berlin.de>
+
+// PR c++/6723
+// ICE when default template argument contains instantiation of
+// template template parameter.
+
+template <typename A, typename B,
+	  template <typename,typename> class Predicate,
+	  bool _matches=Predicate<A,B>::answer>
+struct helper { };