libcxx/test/std/utilities/utility/pairs/pairs.pair/ctor.not_constexpr_cxx11.verify.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // REQUIRES: c++11
  10
  11 // <utility>
  12
  13 // Test that only the default constructor is constexpr in C++11
  14
  15 #include <utility>
  16 #include <cassert>
  17
  18 struct ExplicitT {
  19     constexpr explicit ExplicitT(int x) : value(x) {}
  20     constexpr explicit ExplicitT(ExplicitT const& o) : value(o.value) {}
  21     int value;
  22 };
  23
  24 struct ImplicitT {
  25     constexpr ImplicitT(int x) : value(x) {}
  26     constexpr ImplicitT(ImplicitT const& o) : value(o.value) {}
  27     int value;
  28 };
  29
  30 void f() {
  31     {
  32         using P = std::pair<int, int>;
  33         constexpr int x = 42;
  34         constexpr P default_p{};
  35         constexpr P copy_p(default_p);
  36         constexpr P const_U_V(x, x); // expected-error {{must be initialized by a constant expression}}
  37         constexpr P U_V(42, 101); // expected-error {{must be initialized by a constant expression}}
  38     }
  39     {
  40         using P = std::pair<ExplicitT, ExplicitT>;
  41         constexpr std::pair<int, int> other;
  42         constexpr ExplicitT e(99);
  43         constexpr P const_U_V(e, e); // expected-error {{must be initialized by a constant expression}}
  44         constexpr P U_V(42, 101); // expected-error {{must be initialized by a constant expression}}
  45         constexpr P pair_U_V(other); // expected-error {{must be initialized by a constant expression}}
  46     }
  47     {
  48         using P = std::pair<ImplicitT, ImplicitT>;
  49         constexpr std::pair<int, int> other;
  50         constexpr ImplicitT i = 99;
  51         constexpr P const_U_V = {i, i}; // expected-error {{must be initialized by a constant expression}}
  52         constexpr P U_V = {42, 101}; // expected-error {{must be initialized by a constant expression}}
  53         constexpr P pair_U_V = other; // expected-error {{must be initialized by a constant expression}}
  54     }
  55 }