re PR c++/63723 (Narrowing conversion allowed in braced init list in SFINAE context)

2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/63723
	* g++.dg/cpp0x/sfinae54.C: New.

From-SVN: r218880

gcc/testsuite/ChangeLog

 2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>
 
+	PR c++/63723
+	* g++.dg/cpp0x/sfinae54.C: New.
+
+2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>
+
 	PR c++/59204
 	* g++.dg/cpp0x/sfinae53.C: New.
 

gcc/testsuite/g++.dg/cpp0x/sfinae54.C

+// PR c++/63723
+// { dg-do compile { target c++11 } }
+
+template<typename Tp> Tp declval();
+
+template<typename Tp, Tp v>
+struct integral_constant
+{
+  static constexpr Tp value = v;
+  typedef Tp value_type;
+  typedef integral_constant<Tp, v> type;
+  constexpr operator value_type() const { return value; }
+};
+
+typedef integral_constant<bool, true>   true_type;
+typedef integral_constant<bool, false> false_type;
+
+template <typename From, typename To>
+class is_list_convertible_helper
+{
+  template <typename To2>
+  static void requires_conversion(To2 t);
+
+  template <typename From2, typename To2,
+      typename = decltype(requires_conversion<To2>({declval<From2>()}))>
+  static true_type helper(int);
+
+  template <typename From2, typename To2>
+  static false_type helper(...);
+
+public:
+  using type = decltype(helper<From, To>(0));
+};
+
+template <typename From, typename To>
+class is_list_convertible
+  : public is_list_convertible_helper<From, To>::type
+{ };
+
+static_assert(!is_list_convertible<double, int>::value,
+	      "double -> int is narrowing!");