[libcxx-commits] [libcxx] [libc++] P2255R2: Add deleted tuple constructor overloads (PR #205379)

[Yihan Wang via libcxx-commits]

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@@ -0,0 +1,74 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: std-at-least-c++23
+
+// <tuple>
+
+// tuple(UTypes&&... u);
+// tuple(tuple<UTypes...>& u);
+// tuple(const tuple<UTypes...>& u);
+// tuple(tuple<UTypes...>&& u);
+// tuple(const tuple<UTypes...>&& u);
+// tuple(pair<U1, U2>& u);
+// tuple(const pair<U1, U2>& u);
+// tuple(pair<U1, U2>&& u);
+// tuple(const pair<U1, U2>&& u);
+//
+// The constructors above are defined as deleted if reference_constructs_from_temporary_v
+// is true for one of the corresponding tuple elements.
+
+#include <memory>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+struct X {
+  X(int);
+};
+
+static_assert(std::is_constructible_v<std::tuple<const X&>, X&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&>, int>);
+static_assert(!std::is_constructible_v<std::tuple<const X&>, std::tuple<int>&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&>, const std::tuple<int>&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&>, std::tuple<int>&&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&>, const std::tuple<int>&&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&, int>, std::pair<int, int>&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&, int>, const std::pair<int, int>&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&, int>, std::pair<int, int>&&>);
+static_assert(!std::is_constructible_v<std::tuple<const X&, int>, const std::pair<int, int>&&>);
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yronglin wrote:

Done

https://github.com/llvm/llvm-project/pull/205379