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// Copyright (C) 2016-2019 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++11 } }
#include <memory>
template<typename T, typename Args, typename = void>
struct resettable
: std::false_type
{ };
template<typename... T> struct type_list { };
template<typename T, typename... Args>
using reset_result
= decltype(std::shared_ptr<T>{}.reset(std::declval<Args>()...));
template<typename T, typename... Args>
struct resettable<T, type_list<Args...>, reset_result<T, Args...>>
: std::true_type
{ };
template<typename T, typename... Args>
constexpr bool can_reset()
{ return resettable<T, type_list<Args...>>::value; }
template<typename T>
struct Deleter {
void operator()(T*) const;
};
template<typename T>
using Alloc = std::allocator<T>;
struct Base { };
struct Derived : Base { };
// Positive cases:
static_assert( can_reset<const void, void*>(),
"void* convertible to const void*");
static_assert( can_reset<const int, int*>(),
"int* convertible to const int*");
static_assert( can_reset<Base, Derived*>(),
"Derived* convertible to Base*");
static_assert( can_reset<const Base, Derived*>(),
"Derived* convertible to const Base*");
// Negative cases:
static_assert( !can_reset<int, void*>(),
"void* not convertible to int*");
static_assert( !can_reset<int, void*, Deleter<int>>(),
"void* not convertible to int*");
static_assert( !can_reset<int, void*, Deleter<int>, Alloc<int>>(),
"void* not convertible to int*");
static_assert( !can_reset<int, const int*>(),
"const int* not convertible to int*");
static_assert( !can_reset<int, const int*, Deleter<int>>(),
"const int* not convertible to int*");
static_assert( !can_reset<int, const int*, Deleter<int>, Alloc<int>>(),
"const int* not convertible to int*");
static_assert( !can_reset<int, long*>(),
"long* not convertible to int*");
static_assert( !can_reset<int, long*, Deleter<int>>(),
"long* not convertible to int*");
static_assert( !can_reset<int, long*, Deleter<int>, Alloc<int>>(),
"long* not convertible to int*");
static_assert( !can_reset<Derived, Base*>(),
"Base* not convertible to Derived*");
static_assert( !can_reset<Derived, Base*, Deleter<int>>(),
"Base* not convertible to Derived*");
static_assert( !can_reset<Derived, Base*, Deleter<int>, Alloc<int>>(),
"Base* not convertible to Derived*");
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