* g++.dg/cpp2a/is-constant-evaluated8.C: New test.

From-SVN: r271538

gcc/testsuite/ChangeLog

+2019-05-23  Jakub Jelinek  <jakub@redhat.com>
+
+	* g++.dg/cpp2a/is-constant-evaluated8.C: New test.
+
 2019-05-23  Hans-Peter Nilsson  <hp@axis.com>
 
 	* gfortran.dg/dec_io_1.f90, gfortran.dg/dtio_1.f90,

gcc/testsuite/g++.dg/cpp2a/is-constant-evaluated8.C

+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+namespace std {
+  constexpr inline bool
+  is_constant_evaluated () noexcept
+  {
+    return __builtin_is_constant_evaluated ();
+  }
+}
+
+struct A { explicit (!__builtin_is_constant_evaluated ()) A (int); };	// { dg-warning "'explicit\\(bool\\)' only available with" "" { target c++17_down } }
+struct B { explicit (!std::is_constant_evaluated ()) B (int); };	// { dg-warning "'explicit\\(bool\\)' only available with" "" { target c++17_down } }
+struct C { explicit (__builtin_is_constant_evaluated ()) C (int); };	// { dg-warning "'explicit\\(bool\\)' only available with" "" { target c++17_down } }
+struct D { explicit (std::is_constant_evaluated ()) D (int); };		// { dg-warning "'explicit\\(bool\\)' only available with" "" { target c++17_down } }
+A a = 1;
+B b = 2;
+C c = 3;	// { dg-error "conversion from 'int' to non-scalar type 'C' requested" }
+D d = 4;	// { dg-error "conversion from 'int' to non-scalar type 'D' requested" }