libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.constructible/1.cc

// Copyright (C) 2019-2025 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/>.

// { dg-do compile { target c++20 } }

#include <concepts>

static_assert( !std::constructible_from<void> );
static_assert( !std::constructible_from<void, void> );
static_assert( std::constructible_from<void*, int*> );
static_assert( !std::constructible_from<void*, const int*> );
static_assert( std::constructible_from<const void*, const int*> );
static_assert( std::constructible_from<char> );
static_assert( std::constructible_from<float> );
static_assert( std::constructible_from<float, float> );
static_assert( std::constructible_from<float, double> );
static_assert( std::constructible_from<int*> );
static_assert( std::constructible_from<int*, int*> );
static_assert( !std::constructible_from<int&> );
static_assert( std::constructible_from<int&, int&> );
static_assert( !std::constructible_from<int&&> );
static_assert( std::constructible_from<int&&, int> );
static_assert( !std::constructible_from<const int&> );
static_assert( std::constructible_from<const int&, int> );
static_assert( std::constructible_from<const int&, int&> );
static_assert( std::constructible_from<const int&, const int> );
static_assert( std::constructible_from<const int&, const int&> );
static_assert( !std::constructible_from<const int&, int, int> );
static_assert( !std::constructible_from<int[]> );
static_assert( std::constructible_from<int[2]> );
static_assert( !std::constructible_from<int()> );
static_assert( std::constructible_from<int(*)()> );
static_assert( std::constructible_from<int(*)(), std::nullptr_t> );
static_assert( std::constructible_from<int(*)(), int(*)() noexcept> );
static_assert( std::constructible_from<int(*)(), int(&)() noexcept> );
static_assert( !std::constructible_from<int(&)()> );
static_assert( std::constructible_from<int(&)(), int(&)() noexcept> );

enum E { };
static_assert( std::constructible_from<E> );
static_assert( std::constructible_from<E, E&> );
enum class CE { };
static_assert( std::constructible_from<CE> );
static_assert( std::constructible_from<CE, CE&> );
struct A { };
static_assert( std::constructible_from<A> );
static_assert( std::constructible_from<A, A> );
static_assert( std::constructible_from<A, A&> );
static_assert( std::constructible_from<A, const A&> );
union B { };
static_assert( std::constructible_from<B> );
static_assert( std::constructible_from<B, B> );
static_assert( std::constructible_from<B, B&> );
static_assert( std::constructible_from<B, const B&> );

struct C
{
  C(void* = nullptr) { }
  ~C() noexcept(false) { }
};
static_assert( !std::constructible_from<C> );
static_assert( !std::constructible_from<C, void*> );
static_assert( !std::constructible_from<C, std::nullptr_t> );

class D
{
public:
  D() { }
  D(int) { }
private:
  ~D() { }
};
static_assert( !std::constructible_from<D> );
static_assert( !std::constructible_from<D, int> );