libcxx/test/std/iterators/iterator.requirements/alg.req.ind.copy/indirectly_copyable.compile.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03, c++11, c++14, c++17

// template<class In, class Out>
// concept indirectly_copyable;

#include <iterator>

#include "MoveOnly.h"
#include "test_macros.h"

struct CopyOnly {
  CopyOnly() = default;

  CopyOnly(CopyOnly const&) = default;
  CopyOnly& operator=(CopyOnly const&) = default;

  CopyOnly(CopyOnly&&) = delete;
  CopyOnly& operator=(CopyOnly&&) = delete;
};

// Can copy the underlying objects between pointers.
static_assert( std::indirectly_copyable<int*, int*>);
static_assert( std::indirectly_copyable<const int*, int *>);

// Can't copy if the output pointer is const.
static_assert(!std::indirectly_copyable<int*, const int *>);
static_assert(!std::indirectly_copyable<const int*, const int *>);

// Can copy from a pointer into an array but arrays aren't considered indirectly copyable-from.
static_assert( std::indirectly_copyable<int*, int[2]>);
static_assert(!std::indirectly_copyable<int[2], int*>);
static_assert(!std::indirectly_copyable<int[2], int[2]>);
static_assert(!std::indirectly_copyable<int(&)[2], int(&)[2]>);

// Can't copy between non-pointer types.
static_assert(!std::indirectly_copyable<int*, int>);
static_assert(!std::indirectly_copyable<int, int*>);
static_assert(!std::indirectly_copyable<int, int>);

// Check some less common types.
static_assert(!std::indirectly_movable<void*, void*>);
static_assert(!std::indirectly_movable<int*, void*>);
static_assert(!std::indirectly_movable<int(), int()>);
static_assert(!std::indirectly_movable<int*, int()>);
static_assert(!std::indirectly_movable<void, void>);

// Can't copy move-only objects.
static_assert(!std::indirectly_copyable<MoveOnly*, MoveOnly*>);
static_assert(!std::indirectly_copyable<MoveOnly*, const MoveOnly*>);
static_assert(!std::indirectly_copyable<const MoveOnly*, MoveOnly*>);
static_assert(!std::indirectly_copyable<const MoveOnly*, const MoveOnly*>);

// Can copy copy-only objects.
static_assert( std::indirectly_copyable<CopyOnly*, CopyOnly*>);
static_assert(!std::indirectly_copyable<CopyOnly*, const CopyOnly*>);
static_assert( std::indirectly_copyable<const CopyOnly*, CopyOnly*>);
static_assert(!std::indirectly_copyable<const CopyOnly*, const CopyOnly*>);

template<class T>
struct PointerTo {
  using value_type = T;
  T& operator*() const;
};

// Can copy through a dereferenceable class.
static_assert( std::indirectly_copyable<int*, PointerTo<int>>);
static_assert(!std::indirectly_copyable<int*, PointerTo<const int>>);
static_assert( std::indirectly_copyable<PointerTo<int>, PointerTo<int>>);
static_assert(!std::indirectly_copyable<PointerTo<int>, PointerTo<const int>>);
static_assert( std::indirectly_copyable<CopyOnly*, PointerTo<CopyOnly>>);
static_assert( std::indirectly_copyable<PointerTo<CopyOnly>, CopyOnly*>);
static_assert( std::indirectly_copyable<PointerTo<CopyOnly>, PointerTo<CopyOnly>>);