--- /dev/null
+// { dg-options "-std=c++11" }
+// { dg-do compile }
+
+// Copyright (C) 2012 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <type_traits>
+#include <initializer_list>
+
+//TODO: Uncomment this once gcc bug 53000 has been resolved:
+//#define HAS_53000_FIXED
+
+// Helper types:
+struct has_type_impl
+{
+ template<typename T, typename = typename T::type>
+ static std::true_type test(int);
+ template<typename>
+ static std::false_type test(...);
+};
+
+template<typename T>
+struct has_type : public decltype(has_type_impl::test<T>(0))
+{};
+
+template<typename T, typename Expected>
+struct is_expected_type : public std::is_same<typename T::type, Expected>
+{};
+
+template<typename P1, typename P2>
+struct and_ : public std::conditional<P1::value, P2, std::false_type>::type
+{};
+
+template<typename T, typename Expected>
+struct is_type : public and_<has_type<T>, is_expected_type<T, Expected>>
+{};
+
+// Inspection types:
+
+struct S {};
+
+struct B {};
+struct D : B {};
+
+struct F1 { operator void*(); };
+struct F2 { operator void*(); };
+
+struct G1 { operator const void*(); };
+struct G2 { operator volatile void*(); };
+
+template<typename T>
+struct ImplicitTo
+{
+ operator T();
+};
+
+template<typename T>
+struct ExplicitTo
+{
+ explicit operator T();
+};
+
+template<typename T>
+struct PrivateImplicitTo
+{
+private:
+ operator T();
+};
+
+auto lmd1 = [](int, double) {};
+auto lmd2 = [](int, double) {};
+
+struct Abstract
+{
+ virtual ~Abstract() = 0;
+};
+
+enum class ScEn;
+
+enum UnscEn : int;
+
+struct Ukn;
+
+union U
+{
+ int i;
+};
+
+union U2
+{
+ long i;
+};
+
+union UConv1
+{
+ operator Abstract*();
+};
+
+union UConv2
+{
+ operator Abstract*();
+};
+
+struct X1 {};
+struct X2 {};
+struct RX12 {};
+struct RX21 {};
+struct Y1 {};
+struct Y2 {};
+struct Y3 {};
+struct Y4 {};
+
+namespace std {
+
+ template<>
+ struct common_type<X1, X2>
+ {
+ typedef RX12 type;
+ };
+
+ template<>
+ struct common_type<X2, X1>
+ {
+ typedef RX21 type;
+ };
+
+ template<>
+ struct common_type<RX12, X1>
+ {
+ typedef Y1 type;
+ };
+
+ template<>
+ struct common_type<X1, RX12>
+ {
+ typedef Y2 type;
+ };
+
+ template<>
+ struct common_type<RX21, X1>
+ {
+ typedef Y3 type;
+ };
+
+ template<>
+ struct common_type<X1, RX21>
+ {
+ typedef Y4 type;
+ };
+}
+
+static_assert(is_type<std::common_type<int, int>, int>(), "");
+static_assert(is_type<std::common_type<ScEn, ScEn>, ScEn>(), "");
+static_assert(is_type<std::common_type<UnscEn, UnscEn>, UnscEn>(), "");
+static_assert(is_type<std::common_type<int, int>, int>(), "");
+static_assert(is_type<std::common_type<UnscEn, int>, int>(), "");
+static_assert(is_type<std::common_type<int, int, int>, int>(), "");
+static_assert(is_type<std::common_type<int, int, int, int>, int>(), "");
+static_assert(is_type<std::common_type<int, int, int, int, int>, int>(), "");
+static_assert(is_type<std::common_type<S, S>, S>(), "");
+static_assert(is_type<std::common_type<const S, const S>, S>(), "");
+static_assert(is_type<std::common_type<std::initializer_list<int>,
+ std::initializer_list<int>>, std::initializer_list<int>>(), "");
+static_assert(is_type<std::common_type<B, D>, B>(), "");
+static_assert(is_type<std::common_type<D, B>, B>(), "");
+static_assert(is_type<std::common_type<F1, F2>, void*>(), "");
+static_assert(is_type<std::common_type<F2, F1>, void*>(), "");
+static_assert(is_type<std::common_type<G1, G2>, const volatile void*>(), "");
+static_assert(is_type<std::common_type<G2, G1>, const volatile void*>(), "");
+static_assert(is_type<std::common_type<int*, const volatile int*>,
+ const volatile int*>(), "");
+static_assert(is_type<std::common_type<void*, const volatile int*>,
+ const volatile void*>(), "");
+static_assert(is_type<std::common_type<void, void>, void>(), "");
+static_assert(is_type<std::common_type<const void, const void>, void>(), "");
+static_assert(is_type<std::common_type<int&, int&&>, int>(), "");
+static_assert(is_type<std::common_type<int&, int&>, int>(), "");
+static_assert(is_type<std::common_type<int&&, int&&>, int>(), "");
+static_assert(is_type<std::common_type<U&, const U&&>, U>(), "");
+static_assert(is_type<std::common_type<U&, U&>, U>(), "");
+static_assert(is_type<std::common_type<U&&, U&&>, U>(), "");
+static_assert(is_type<std::common_type<int B::*, int D::*>, int D::*>(), "");
+static_assert(is_type<std::common_type<int D::*, int B::*>, int D::*>(), "");
+static_assert(is_type<std::common_type<const int B::*, volatile int D::*>,
+ const volatile int D::*>(), "");
+static_assert(is_type<std::common_type<int (B::*)(), int (D::*)()>,
+ int (D::*)()>(), "");
+static_assert(is_type<std::common_type<int (B::*)() const, int (D::*)() const>,
+ int (D::*)() const>(), "");
+static_assert(is_type<std::common_type<int[3], int[3]>, int*>(), "");
+static_assert(is_type<std::common_type<int[1], const int[3]>,
+ const int*>(), "");
+static_assert(is_type<std::common_type<void(), void()>, void(*)()>(), "");
+static_assert(is_type<std::common_type<void(&)(), void(&)()>, void(*)()>(), "");
+static_assert(is_type<std::common_type<void(&)(), void(&&)()>,
+ void(*)()>(), "");
+static_assert(is_type<std::common_type<void(&&)(), void(&)()>,
+ void(*)()>(), "");
+static_assert(is_type<std::common_type<void(&&)(), void(&&)()>,
+ void(*)()>(), "");
+static_assert(is_type<std::common_type<ImplicitTo<int>, int>, int>(), "");
+static_assert(is_type<std::common_type<ImplicitTo<int>, ImplicitTo<int>>,
+ ImplicitTo<int>>(), "");
+static_assert(is_type<std::common_type<ImplicitTo<int>, int,
+ ImplicitTo<int>>, int>(), "");
+static_assert(is_type<std::common_type<ExplicitTo<int>, ExplicitTo<int>>,
+ ExplicitTo<int>>(), "");
+static_assert(is_type<std::common_type<decltype(lmd1), decltype(lmd1)>,
+ decltype(lmd1)>(), "");
+static_assert(is_type<std::common_type<decltype(lmd1)&, decltype(lmd1)&>,
+ decltype(lmd1)>(), "");
+static_assert(is_type<std::common_type<decltype(lmd1)&, decltype(lmd2)&>,
+ void(*)(int, double)>(), "");
+static_assert(is_type<std::common_type<decltype(nullptr), void*>, void*>(), "");
+static_assert(is_type<std::common_type<decltype(nullptr), int*>, int*>(), "");
+static_assert(is_type<std::common_type<const decltype(nullptr)&, int*>,
+ int*>(), "");
+static_assert(is_type<std::common_type<decltype(nullptr), const volatile int*>,
+ const volatile int*>(), "");
+static_assert(is_type<std::common_type<decltype(nullptr), int (B::*)()>,
+ int (B::*)()>(), "");
+static_assert(is_type<std::common_type<decltype(nullptr), int (B::*)() const>,
+ int (B::*)() const>(), "");
+static_assert(is_type<std::common_type<decltype(nullptr), const int B::*>,
+ const int B::*>(), "");
+static_assert(is_type<std::common_type<Abstract&, Abstract&>, Abstract>(), "");
+static_assert(is_type<std::common_type<Ukn&, Ukn&>, Ukn>(), "");
+static_assert(is_type<std::common_type<ImplicitTo<B&>, B&>, B>(), "");
+static_assert(is_type<std::common_type<ImplicitTo<B&>&, B&&>, B>(), "");
+static_assert(is_type<std::common_type<UConv1, const Abstract*&>,
+ const Abstract*>(), "");
+static_assert(is_type<std::common_type<UConv1, UConv2>, Abstract*>(), "");
+static_assert(is_type<std::common_type<UConv1&, UConv2&>, Abstract*>(), "");
+
+#ifdef HAS_53000_FIXED
+static_assert(is_type<std::common_type<Abstract&&, Abstract&&>,
+ Abstract>(), "");
+static_assert(is_type<std::common_type<const Abstract&&,
+ volatile Abstract&&>, Abstract>(), "");
+static_assert(is_type<std::common_type<Ukn&&, Ukn&&>, Ukn>(), "");
+static_assert(is_type<std::common_type<const Ukn&&, volatile Ukn&&>,
+ Ukn>(), "");
+#endif
+
+static_assert(is_type<std::common_type<X1, X2>, RX12>(), "");
+static_assert(is_type<std::common_type<X2, X1>, RX21>(), "");
+
+static_assert(is_type<std::common_type<X1, X2, X1>, Y1>(), "");
+static_assert(is_type<std::common_type<X2, X1, X1>, Y3>(), "");
+
+static_assert(is_type<std::common_type<X1, X1, X2>, RX12>(), "");
+static_assert(is_type<std::common_type<X1, X1, X2, X1>, Y1>(), "");
+
+static_assert(!has_type<std::common_type<>>(), "");
+static_assert(!has_type<std::common_type<int, S>>(), "");
+static_assert(!has_type<std::common_type<U, S>>(), "");
+static_assert(!has_type<std::common_type<U, U2>>(), "");
+static_assert(!has_type<std::common_type<const ImplicitTo<int>, int>>(), "");
+static_assert(!has_type<std::common_type<PrivateImplicitTo<int>, int>>(), "");
+static_assert(!has_type<std::common_type<const PrivateImplicitTo<int>,
+ int>>(), "");
+static_assert(!has_type<std::common_type<int, Ukn>>(), "");
+static_assert(!has_type<std::common_type<int, Abstract>>(), "");
+static_assert(!has_type<std::common_type<Ukn, Abstract>>(), "");
+static_assert(!has_type<std::common_type<int, void>>(), "");
+static_assert(!has_type<std::common_type<int, const volatile void>>(), "");
+static_assert(!has_type<std::common_type<Abstract, void>>(), "");
+static_assert(!has_type<std::common_type<Ukn, void>>(), "");
+static_assert(!has_type<std::common_type<int[4], void>>(), "");
+static_assert(!has_type<std::common_type<ScEn, void>>(), "");
+static_assert(!has_type<std::common_type<UnscEn, void>>(), "");
+static_assert(!has_type<std::common_type<U, void>>(), "");
+static_assert(!has_type<std::common_type<std::initializer_list<int>,
+ void>>(), "");
+static_assert(!has_type<std::common_type<int, int, int, S>>(), "");
+static_assert(!has_type<std::common_type<int, int, S, int>>(), "");
+static_assert(!has_type<std::common_type<int, S, int, int>>(), "");
+static_assert(!has_type<std::common_type<S, int, int, int>>(), "");
+static_assert(!has_type<std::common_type<int, int, void, int, int>>(), "");
+static_assert(!has_type<std::common_type<B, S>>(), "");
+static_assert(!has_type<std::common_type<int, B, S>>(), "");
+static_assert(!has_type<std::common_type<B, int, S>>(), "");
+static_assert(!has_type<std::common_type<B, S, int>>(), "");
+static_assert(!has_type<std::common_type<int*, double*>>(), "");
+static_assert(!has_type<std::common_type<void*, void(*)(...)>>(), "");
+static_assert(!has_type<std::common_type<void(*)(), void(*)(...)>>(), "");
+static_assert(!has_type<std::common_type<void(*)(), void(S::*)()>>(), "");
+static_assert(!has_type<std::common_type<void(S::*)() const,
+ void(S::*)()>>(), "");
+static_assert(!has_type<std::common_type<int S::*, long S::*>>(), "");
+static_assert(!has_type<std::common_type<int S::*, void(S::*)()>>(), "");
+static_assert(!has_type<std::common_type<int (B::*)(),
+ int (D::*)() const>>(), "");
+static_assert(!has_type<std::common_type<int (B::*)() const,
+ int (D::*)()>>(), "");
+static_assert(!has_type<std::common_type<int, ExplicitTo<int>>>(), "");
+static_assert(!has_type<std::common_type<ImplicitTo<int>,
+ ExplicitTo<int>>>(), "");
+static_assert(!has_type<std::common_type<ScEn, int>>(), "");
+static_assert(!has_type<std::common_type<ScEn, UnscEn>>(), "");
+static_assert(!has_type<std::common_type<U, S, Abstract, void, D,
+ int (B::*)(), int[5]>>(), "");
+static_assert(!has_type<std::common_type<UConv1, Abstract&&>>(), "");
+static_assert(!has_type<std::common_type<std::initializer_list<int>,
+ std::initializer_list<long>>>(), "");
+
+void test(int i)
+{
+ auto local_lmd1 = [=](int, double) { return i + i; };
+ auto local_lmd2 = [=](int, double) { return i - i; };
+
+ static_assert(is_type<std::common_type<decltype(local_lmd1),
+ decltype(local_lmd1)>, decltype(local_lmd1)>(), "");
+ static_assert(is_type<std::common_type<decltype(local_lmd1)&,
+ decltype(local_lmd1)>, decltype(local_lmd1)>(), "");
+ static_assert(is_type<std::common_type<decltype(local_lmd1)&,
+ decltype(local_lmd1)&>, decltype(local_lmd1)>(), "");
+
+ static_assert(!has_type<std::common_type<decltype(local_lmd1),
+ decltype(lmd1)>>(), "");
+ static_assert(!has_type<std::common_type<decltype(local_lmd1)&,
+ decltype(lmd1)&>>(), "");
+ static_assert(!has_type<std::common_type<decltype(local_lmd1),
+ decltype(local_lmd2)>>(), "");
+ static_assert(!has_type<std::common_type<decltype(local_lmd1)&,
+ decltype(local_lmd2)&>>(), "");
+}