Fix read of uninitialized value in make_pack_expansion()

gcc/cp/ChangeLog:

	* pt.c (make_pack_expansion): Make sure to initialize
	ppd.type_pack_expansion_p.

From-SVN: r231904

gcc/cp/ChangeLog

+2015-12-22  Patrick Palka  <ppalka@gcc.gnu.org>
+
+	* pt.c (make_pack_expansion): Make sure to initialize
+	ppd.type_pack_expansion_p.
+
 2015-12-21  David Malcolm  <dmalcolm@redhat.com>
 
 	* typeck.c (cp_build_binary_op): Update for change in signature

gcc/cp/pt.c

@@ -3637,6 +3637,8 @@ make_pack_expansion (tree arg)
          class expansion.  */
       ppd.visited = new hash_set<tree>;
       ppd.parameter_packs = &parameter_packs;
+      ppd.type_pack_expansion_p = true;
+      gcc_assert (TYPE_P (TREE_PURPOSE (arg)));
       cp_walk_tree (&TREE_PURPOSE (arg), &find_parameter_packs_r, 
                     &ppd, ppd.visited);