diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 0c759c6..2643e8c 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -4589,8 +4589,8 @@ struct arg_lookup
 {
   tree name;
   VEC(tree,gc) *args;
-  tree namespaces;
-  tree classes;
+  VEC(tree,gc) *namespaces;
+  VEC(tree,gc) *classes;
   tree functions;
 };
 
@@ -4667,9 +4667,9 @@ arg_assoc_namespace (struct arg_lookup *k, tree scope)
 {
   tree value;
 
-  if (purpose_member (scope, k->namespaces))
-    return 0;
-  k->namespaces = tree_cons (scope, NULL_TREE, k->namespaces);
+  if (vec_member (scope, k->namespaces))
+    return false;
+  VEC_safe_push (tree, gc, k->namespaces, scope);
 
   /* Check out our super-users.  */
   for (value = DECL_NAMESPACE_ASSOCIATIONS (scope); value;
@@ -4850,9 +4850,9 @@ arg_assoc_class (struct arg_lookup *k, tree type)
   if (!CLASS_TYPE_P (type))
     return false;
 
-  if (purpose_member (type, k->classes))
+  if (vec_member (type, k->classes))
     return false;
-  k->classes = tree_cons (type, NULL_TREE, k->classes);
+  VEC_safe_push (tree, gc, k->classes, type);
 
   if (TYPE_CLASS_SCOPE_P (type)
       && arg_assoc_class_only (k, TYPE_CONTEXT (type)))
@@ -5049,14 +5049,14 @@ lookup_arg_dependent (tree name, tree fns, VEC(tree,gc) *args)
   k.name = name;
   k.args = args;
   k.functions = fns;
-  k.classes = NULL_TREE;
+  k.classes = make_tree_vector ();
 
   /* We previously performed an optimization here by setting
      NAMESPACES to the current namespace when it was safe. However, DR
      164 says that namespaces that were already searched in the first
      stage of template processing are searched again (potentially
      picking up later definitions) in the second stage. */
-  k.namespaces = NULL_TREE;
+  k.namespaces = make_tree_vector ();
 
   arg_assoc_args_vec (&k, args);
 
@@ -5070,6 +5070,9 @@ lookup_arg_dependent (tree name, tree fns, VEC(tree,gc) *args)
       error ("  in call to %qD", name);
       fns = error_mark_node;
     }
+
+  release_tree_vector (k.classes);
+  release_tree_vector (k.namespaces);
     
   POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, fns);
 }
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index e7b97c4..7aed503 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -1419,18 +1419,14 @@ build_x_arrow (tree expr)
 				   /*overloaded_p=*/NULL, 
 				   tf_warning_or_error)))
 	{
-	  tree t;
-	  unsigned ix;
-
 	  if (expr == error_mark_node)
 	    return error_mark_node;
 
-	  for (ix = 0; VEC_iterate (tree, types_memoized, ix, t); ix++)
-	    if (TREE_TYPE (expr) == t)
-	      {
-		error ("circular pointer delegation detected");
-		return error_mark_node;
-	      }
+	  if (vec_member (TREE_TYPE (expr), types_memoized))
+	    {
+	      error ("circular pointer delegation detected");
+	      return error_mark_node;
+	    }
 
 	  VEC_safe_push (tree, gc, types_memoized, TREE_TYPE (expr));
 	  last_rval = expr;
diff --git a/gcc/tree.c b/gcc/tree.c
index 67e2f41..cb8e4fe 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -1923,6 +1923,19 @@ purpose_member (const_tree elem, tree list)
   return NULL_TREE;
 }
 
+/* Return true if ELEM is in V.  */
+
+bool
+vec_member (const_tree elem, VEC(tree,gc) *v)
+{
+  unsigned ix;
+  tree t;
+  for (ix = 0; VEC_iterate (tree, v, ix, t); ix++)
+    if (elem == t)
+      return true;
+  return false;
+}
+
 /* Returns element number IDX (zero-origin) of chain CHAIN, or
    NULL_TREE.  */
 
diff --git a/gcc/tree.h b/gcc/tree.h
index 13c684a..a70608e 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -4086,6 +4086,7 @@ extern bool range_in_array_bounds_p (tree);
 
 extern tree value_member (tree, tree);
 extern tree purpose_member (const_tree, tree);
+extern bool vec_member (const_tree, VEC(tree,gc) *);
 extern tree chain_index (int, tree);
 
 extern int attribute_list_equal (const_tree, const_tree);