| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| // UNSUPPORTED: libcpp-no-concepts |
| // UNSUPPORTED: libcpp-has-no-incomplete-ranges |
| |
| // __non_propagating_cache& operator=(__non_propagating_cache const&); |
| |
| // ADDITIONAL_COMPILE_FLAGS: -Wno-self-assign |
| |
| #include <ranges> |
| |
| #include <cassert> |
| #include <type_traits> |
| #include <utility> |
| |
| template<bool NoexceptCopy> |
| struct CopyAssignable { |
| int x; |
| constexpr explicit CopyAssignable(int i) : x(i) { } |
| CopyAssignable(CopyAssignable const&) = default; |
| constexpr CopyAssignable& operator=(CopyAssignable const& other) noexcept(NoexceptCopy) { |
| x = other.x; |
| return *this; |
| } |
| constexpr bool operator==(CopyAssignable const& other) const { return x == other.x; } |
| }; |
| |
| struct NotCopyAssignable { |
| int x; |
| constexpr explicit NotCopyAssignable(int i) : x(i) { } |
| NotCopyAssignable(NotCopyAssignable const&) = default; |
| NotCopyAssignable& operator=(NotCopyAssignable const&) = delete; |
| constexpr bool operator==(NotCopyAssignable const& other) const { return x == other.x; } |
| }; |
| |
| template <class T> |
| constexpr void test() { |
| using Cache = std::ranges::__non_propagating_cache<T>; |
| static_assert(std::is_nothrow_copy_assignable_v<Cache>); |
| |
| // Assign to an empty cache |
| { |
| Cache a; a.__emplace(3); |
| Cache b; |
| |
| Cache& result = (b = a); |
| assert(&result == &b); |
| assert(!b.__has_value()); // make sure we don't propagate |
| |
| assert(a.__has_value()); // make sure we don't "steal" from the source |
| assert(*a == T{3}); // |
| } |
| |
| // Assign to a non-empty cache |
| { |
| Cache a; a.__emplace(3); |
| Cache b; b.__emplace(5); |
| |
| Cache& result = (b = a); |
| assert(&result == &b); |
| assert(!b.__has_value()); // make sure we don't propagate |
| |
| assert(a.__has_value()); // make sure we don't "steal" from the source |
| assert(*a == T{3}); // |
| } |
| |
| // Self-assignment should not do anything (case with empty cache) |
| { |
| Cache b; |
| Cache& result = (b = b); |
| assert(&result == &b); |
| assert(!b.__has_value()); |
| } |
| |
| // Self-assignment should not do anything (case with non-empty cache) |
| { |
| Cache b; b.__emplace(5); |
| Cache& result = (b = b); |
| assert(&result == &b); |
| assert(b.__has_value()); |
| assert(*b == T{5}); |
| } |
| } |
| |
| constexpr bool tests() { |
| test<CopyAssignable<true>>(); |
| test<CopyAssignable<false>>(); |
| test<NotCopyAssignable>(); |
| test<int>(); |
| return true; |
| } |
| |
| int main(int, char**) { |
| static_assert(tests()); |
| tests(); |
| return 0; |
| } |