re PR c++/56774 (G++ 4.8 reverses variadic template types during unpacking)

	PR c++/56774
	PR c++/35722
	* pt.c (unify_pack_expansion): Fix indexing.

From-SVN: r197244

gcc/cp/ChangeLog

+2013-03-29  Jason Merrill  <jason@redhat.com>
+
+	PR c++/56774
+	PR c++/35722
+	* pt.c (unify_pack_expansion): Fix indexing.
+
 2013-03-29  Gabriel Dos Reis  <gdr@integrable-solutions.net>
 
 	* call.c (build_java_interface_fn_ref): Likewise.

gcc/cp/pt.c

@@ -16213,10 +16213,10 @@ unify_pack_expansion (tree tparms, tree targs, tree packed_parms,
           arg = NULL_TREE;
           if (TREE_VALUE (pack)
               && (pargs = ARGUMENT_PACK_EXPLICIT_ARGS (TREE_VALUE (pack)))
-              && (i < TREE_VEC_LENGTH (pargs)))
+              && (i - start < TREE_VEC_LENGTH (pargs)))
             {
               any_explicit = true;
-              arg = TREE_VEC_ELT (pargs, i);
+              arg = TREE_VEC_ELT (pargs, i - start);
             }
           TMPL_ARG (targs, level, idx) = arg;
         }

gcc/testsuite/g++.dg/cpp0x/variadic-explicit2.C

+// PR c++/56774
+// { dg-require-effective-target c++11 }
+
+template <class ... Args>
+struct mytype {};
+
+template <class T, class ... Args>
+void something( mytype<T, Args...> )
+{ }
+
+int main()
+{
+  something<int, char, bool>( mytype<int, char, bool>() );
+}