2012-12-06  Jason Merrill  <jason@redhat.com>
 
	PR c++/54653
	* parser.c (cp_parser_class_head): A partial specialization scope
	counts as a template.
	* pt.c (tsubst_template_parms): Handle template template parm parms.
	(tsubst_decl) [TEMPLATE_DECL]: Handle getting a template template
	argument back.

--- gcc/testsuite/g++.dg/template/partial-specialization2.C	(revision 0)
+++ gcc/testsuite/g++.dg/template/partial-specialization2.C	(revision 194249)
@@ -0,0 +1,8 @@
+// PR c++/54653
+
+template <class T> struct A;
+template <class T> struct A<T*> {
+  template <class U> struct B;
+};
+
+template <class T> struct A<T*>::B<T*> { }; // { dg-error "too few template-parameter-lists" }
--- gcc/cp/pt.c	(revision 194248)
+++ gcc/cp/pt.c	(revision 194249)
@@ -7959,7 +7959,7 @@ tsubst_template_parms (tree parms, tree
   ++processing_template_decl;
 
   for (new_parms = &r;
-       TMPL_PARMS_DEPTH (parms) > TMPL_ARGS_DEPTH (args);
+       parms && TMPL_PARMS_DEPTH (parms) > TMPL_ARGS_DEPTH (args);
        new_parms = &(TREE_CHAIN (*new_parms)),
 	 parms = TREE_CHAIN (parms))
     {
@@ -8203,6 +8203,10 @@ tsubst_decl (tree t, tree args, tsubst_f
 	    tree new_type = tsubst (TREE_TYPE (t), args, complain, in_decl);
 	    if (new_type == error_mark_node)
 	      return error_mark_node;
+	    /* If we get a real template back, return it.  This can happen in
+	       the context of most_specialized_class.  */
+	    if (TREE_CODE (new_type) == TEMPLATE_DECL)
+	      return new_type;
 
 	    r = copy_decl (t);
 	    TREE_CHAIN (r) = NULL_TREE;
--- gcc/cp/parser.c	(revision 194248)
+++ gcc/cp/parser.c	(revision 194249)
@@ -15405,7 +15405,8 @@ cp_parser_class_head (cp_parser* parser,
 		&& CLASS_TYPE_P (scope)
 		&& CLASSTYPE_TEMPLATE_INFO (scope)
 		&& PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (scope))
-		&& !CLASSTYPE_TEMPLATE_SPECIALIZATION (scope))
+		&& (!CLASSTYPE_TEMPLATE_SPECIALIZATION (scope)
+		    || uses_template_parms (CLASSTYPE_TI_ARGS (scope))))
 	      ++num_templates;
 	}
     }