PR c++/72764 - ICE with invalid template typename.

	* decl.c (build_typename_type): No longer static.
	* tree.c (strip_typedefs): Use it instead of make_typename_type.

From-SVN: r249760

gcc/cp/ChangeLog

 2017-06-28  Jason Merrill  <jason@redhat.com>
 
+	PR c++/72764 - ICE with invalid template typename.
+	* decl.c (build_typename_type): No longer static.
+	* tree.c (strip_typedefs): Use it instead of make_typename_type.
+
 	PR c++/69300 - ICE with self-referential noexcept
 	* pt.c (maybe_instantiate_noexcept): Check for recursion.
 

gcc/cp/cp-tree.h

@@ -6087,6 +6087,7 @@ extern tree define_label			(location_t, tree);
 extern void check_goto				(tree);
 extern bool check_omp_return			(void);
 extern tree make_typename_type			(tree, tree, enum tag_types, tsubst_flags_t);
+extern tree build_typename_type			(tree, tree, tree, tag_types);
 extern tree make_unbound_class_template		(tree, tree, tree, tsubst_flags_t);
 extern tree build_library_fn_ptr		(const char *, tree, int);
 extern tree build_cp_library_fn_ptr		(const char *, tree, int);

gcc/cp/decl.c

@@ -3594,7 +3594,7 @@ struct typename_hasher : ggc_ptr_hash<tree_node>
 
 static GTY (()) hash_table<typename_hasher> *typename_htab;
 
-static tree
+tree
 build_typename_type (tree context, tree name, tree fullname,
 		     enum tag_types tag_type)
 {

gcc/cp/tree.c

@@ -1503,13 +1503,13 @@ strip_typedefs (tree t, bool *remove_attributes)
       break;
     case TYPENAME_TYPE:
       {
+	bool changed = false;
 	tree fullname = TYPENAME_TYPE_FULLNAME (t);
 	if (TREE_CODE (fullname) == TEMPLATE_ID_EXPR
 	    && TREE_OPERAND (fullname, 1))
 	  {
 	    tree args = TREE_OPERAND (fullname, 1);
 	    tree new_args = copy_node (args);
-	    bool changed = false;
 	    for (int i = 0; i < TREE_VEC_LENGTH (args); ++i)
 	      {
 		tree arg = TREE_VEC_ELT (args, i);
@@ -1533,12 +1533,15 @@ strip_typedefs (tree t, bool *remove_attributes)
 	    else
 	      ggc_free (new_args);
 	  }
-	result = make_typename_type (strip_typedefs (TYPE_CONTEXT (t),
-						     remove_attributes),
-				     fullname, typename_type, tf_none);
-	/* Handle 'typedef typename A::N N;'  */
-	if (typedef_variant_p (result))
-	  result = TYPE_MAIN_VARIANT (DECL_ORIGINAL_TYPE (TYPE_NAME (result)));
+	tree ctx = strip_typedefs (TYPE_CONTEXT (t), remove_attributes);
+	if (!changed && ctx == TYPE_CONTEXT (t) && !typedef_variant_p (t))
+	  return t;
+	tree name = fullname;
+	if (TREE_CODE (fullname) == TEMPLATE_ID_EXPR)
+	  name = TREE_OPERAND (fullname, 0);
+	/* Use build_typename_type rather than make_typename_type because we
+	   don't want to resolve it here, just strip typedefs.  */
+	result = build_typename_type (ctx, name, fullname, typename_type);
       }
       break;
     case DECLTYPE_TYPE:

gcc/testsuite/g++.dg/cpp0x/alias-decl-60.C

+// PR c++/72764
+// { dg-do compile { target c++11 } }
+
+template < typename > struct A;
+template < typename > struct B {};
+
+template < typename T >
+using C = typename A < T >::template D < T >;
+
+template < typename T > struct A
+{ 
+  // should be: template < typename > struct D : B < C < T > > {};
+  struct D : B < C < T > > {};	// { dg-error "not a class template" }
+};
+
+A < int >::D a;			// { dg-message "required" }