re PR c++/59204 (Incorrect metaprogram evaluation in SFINAE context)

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

	PR c++/59204
	* g++.dg/cpp0x/sfinae53.C: New.

From-SVN: r218878

gcc/testsuite/ChangeLog

+2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/59204
+	* g++.dg/cpp0x/sfinae53.C: New.
+
 2014-12-18  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR rtl-optimization/64291

gcc/testsuite/g++.dg/cpp0x/sfinae53.C

+// PR c++/59204
+// { dg-do compile { target c++11 } }
+
+template< class T >
+  using void_t = void;
+
+template< class T, class = void >
+  struct has_type
+{ constexpr static bool value = false; };
+
+template< class T >
+  struct has_type<T, void_t<typename T::type>>
+{ constexpr static bool value = true; };
+
+struct yes  { using type = int; };
+struct no   { };
+
+int
+main( )
+{
+  static_assert(     has_type<yes>::value, "false negative!" );
+  static_assert( not has_type<no >::value, "false positive!" );
+}