1 files changed, 63 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic143.C b/gcc/testsuite/g++.dg/cpp0x/variadic143.C
new file mode 100644
index 0000000000..db0b268e4b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic143.C
@@ -0,0 +1,63 @@
+// PR c++/56782
+// { dg-do compile { target c++11 } }
+
+template<class T>
+T&& declval();
+
+struct is_convertible_impl {
+  template<class T>
+  static void sink(T);
+
+  template<class T, class U, class = decltype(sink<U>(declval<T>()))>
+  static auto test(int) -> char;
+
+  template<class, class>
+  static auto test(...) -> char(&)[2];
+};
+
+template<class T, class U>
+struct is_convertible : is_convertible_impl
+{
+  static const bool value = sizeof(test<T, U>(0)) == 1;
+};
+
+template<bool, class>
+struct enable_if {};
+
+template<class T>
+struct enable_if<true, T> { typedef T type; };
+
+template<bool, class If, class Else>
+struct conditional { typedef If type; };
+
+template<class If, class Else>
+struct conditional<false, If, Else> { typedef Else type; };
+
+template<class...>
+struct and_;
+
+template<>
+struct and_<>
+{
+  static const bool value = true;
+};
+
+template<class P>
+struct and_<P> : P
+{
+};
+
+template<class P1, class P2>
+struct and_<P1, P2> : conditional<P1::value, P2, P1>::type
+{
+};
+
+template<class... T>
+struct Tuple {
+  template<class... U,
+	   class = typename enable_if<and_<is_convertible<U, T>... >::value, int>::type
+	   >
+  Tuple(U&&...){}
+};
+
+static_assert(is_convertible<Tuple<>, Tuple<>>::value, "Ouch"); //#1