[libcxx-commits] [libcxx] [libc++][complex] P2819R2: Add `tuple` protocol to `complex` (PR #79744)

[Mark de Wever via libcxx-commits]

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@@ -0,0 +1,87 @@
+//===----------------------------------------------------------------------===//
+//
+// 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, c++20, c++23
+
+// <complex>
+
+//   template<size_t I, class T>
+//     constexpr T& get(complex<T>&) noexcept;
+//   template<size_t I, class T>
+//     constexpr T&& get(complex<T>&&) noexcept;
+//   template<size_t I, class T>
+//     constexpr const T& get(const complex<T>&) noexcept;
+//   template<size_t I, class T>
+//     constexpr const T&& get(const complex<T>&&) noexcept;
+
+#include <cassert>
+#include <concepts>
+#include <complex>
+#include <utility>
+
+template <typename T>
+constexpr void test() {
+  // &
+  {
+    std::complex<T> c{T{27}, T{28}};
+
+    std::same_as<T&> decltype(auto) r = get<0>(c);
+    static_assert(noexcept(get<0>(c)));
+    assert(r == T{27});
+    std::same_as<T&> decltype(auto) i = get<1>(c);
+    static_assert(noexcept(get<1>(c)));
+    assert(i == T{28});
+  }
+  //  &&
+  {
+    std::complex<T> c{T{27}, T{28}};
+
+    std::same_as<T&&> decltype(auto) r = get<0>(std::move(c));
+    static_assert(noexcept(get<0>(c)));
+    assert(r == T{27});
+    std::same_as<T&&> decltype(auto) i = get<1>(std::move(c));
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mordante wrote:

here you use `c` in a moved-from state.

https://github.com/llvm/llvm-project/pull/79744