[libcxx] adds concept `std::move_constructible`

Implements parts of:
    - P0898R3 Standard Library Concepts
    - P1754 Rename concepts to standard_case for C++20, while we still can

Depends on D77961

Differential Revision: https://reviews.llvm.org/D96230

libcxx/include/concepts

@@ -184,6 +184,11 @@ template<class _Tp>
 concept default_initializable = constructible_from<_Tp> &&
     requires { _Tp{}; } && __default_initializable<_Tp>;
 
+// [concept.moveconstructible]
+template<class _Tp>
+concept move_constructible =
+  constructible_from<_Tp, _Tp> && convertible_to<_Tp, _Tp>;
+
 #endif //_LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
 
 _LIBCPP_END_NAMESPACE_STD

libcxx/test/std/concepts/lang/moveconstructible.compile.pass.cpp

@@ -0,0 +1,77 @@
+//===----------------------------------------------------------------------===//
+//
+// 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++98, c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+
+// template<class T>
+// concept move_constructible;
+
+#include <concepts>
+#include <type_traits>
+
+#include "moveconstructible.h"
+
+static_assert(std::move_constructible<int>);
+static_assert(std::move_constructible<int*>);
+static_assert(std::move_constructible<int&>);
+static_assert(std::move_constructible<int&&>);
+static_assert(std::move_constructible<const int>);
+static_assert(std::move_constructible<const int&>);
+static_assert(std::move_constructible<const int&&>);
+static_assert(std::move_constructible<volatile int>);
+static_assert(std::move_constructible<volatile int&>);
+static_assert(std::move_constructible<volatile int&&>);
+static_assert(std::move_constructible<int (*)()>);
+static_assert(std::move_constructible<int (&)()>);
+static_assert(std::move_constructible<HasDefaultOps>);
+static_assert(std::move_constructible<CustomMoveCtor>);
+static_assert(std::move_constructible<MoveOnly>);
+static_assert(std::move_constructible<const CustomMoveCtor&>);
+static_assert(std::move_constructible<volatile CustomMoveCtor&>);
+static_assert(std::move_constructible<const CustomMoveCtor&&>);
+static_assert(std::move_constructible<volatile CustomMoveCtor&&>);
+static_assert(std::move_constructible<CustomMoveAssign>);
+static_assert(std::move_constructible<const CustomMoveAssign&>);
+static_assert(std::move_constructible<volatile CustomMoveAssign&>);
+static_assert(std::move_constructible<const CustomMoveAssign&&>);
+static_assert(std::move_constructible<volatile CustomMoveAssign&&>);
+static_assert(std::move_constructible<int HasDefaultOps::*>);
+static_assert(std::move_constructible<void (HasDefaultOps::*)(int)>);
+static_assert(std::move_constructible<MemberLvalueReference>);
+static_assert(std::move_constructible<MemberRvalueReference>);
+
+static_assert(!std::move_constructible<void>);
+static_assert(!std::move_constructible<const CustomMoveCtor>);
+static_assert(!std::move_constructible<volatile CustomMoveCtor>);
+static_assert(!std::move_constructible<const CustomMoveAssign>);
+static_assert(!std::move_constructible<volatile CustomMoveAssign>);
+static_assert(!std::move_constructible<int[10]>);
+static_assert(!std::move_constructible<DeletedMoveCtor>);
+static_assert(!std::move_constructible<ImplicitlyDeletedMoveCtor>);
+static_assert(!std::move_constructible<DeletedMoveAssign>);
+static_assert(!std::move_constructible<ImplicitlyDeletedMoveAssign>);
+
+static_assert(std::move_constructible<DeletedMoveCtor&>);
+static_assert(std::move_constructible<DeletedMoveCtor&&>);
+static_assert(std::move_constructible<const DeletedMoveCtor&>);
+static_assert(std::move_constructible<const DeletedMoveCtor&&>);
+static_assert(std::move_constructible<ImplicitlyDeletedMoveCtor&>);
+static_assert(std::move_constructible<ImplicitlyDeletedMoveCtor&&>);
+static_assert(std::move_constructible<const ImplicitlyDeletedMoveCtor&>);
+static_assert(std::move_constructible<const ImplicitlyDeletedMoveCtor&&>);
+static_assert(std::move_constructible<DeletedMoveAssign&>);
+static_assert(std::move_constructible<DeletedMoveAssign&&>);
+static_assert(std::move_constructible<const DeletedMoveAssign&>);
+static_assert(std::move_constructible<const DeletedMoveAssign&&>);
+static_assert(std::move_constructible<ImplicitlyDeletedMoveAssign&>);
+static_assert(std::move_constructible<ImplicitlyDeletedMoveAssign&&>);
+static_assert(std::move_constructible<const ImplicitlyDeletedMoveAssign&>);
+static_assert(std::move_constructible<const ImplicitlyDeletedMoveAssign&&>);
+
+int main(int, char**) { return 0; }

libcxx/test/std/concepts/lang/moveconstructible.h

@@ -0,0 +1,61 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+#ifndef TEST_STD_CONCEPTS_LAND_MOVECONSTRUCTIBLE_H
+#define TEST_STD_CONCEPTS_LAND_MOVECONSTRUCTIBLE_H
+
+struct HasDefaultOps {};
+
+struct CustomMoveCtor {
+  CustomMoveCtor(CustomMoveCtor&&) noexcept;
+};
+
+struct MoveOnly {
+  MoveOnly(MoveOnly&&) noexcept = default;
+  MoveOnly& operator=(MoveOnly&&) noexcept = default;
+  MoveOnly(const MoveOnly&) = delete;
+  MoveOnly& operator=(const MoveOnly&) = default;
+};
+
+struct CustomMoveAssign {
+  CustomMoveAssign(CustomMoveAssign&&) noexcept;
+  CustomMoveAssign& operator=(CustomMoveAssign&&) noexcept;
+};
+
+struct DeletedMoveCtor {
+  DeletedMoveCtor(DeletedMoveCtor&&) = delete;
+};
+
+struct ImplicitlyDeletedMoveCtor {
+  DeletedMoveCtor X;
+};
+
+struct DeletedMoveAssign {
+  DeletedMoveAssign& operator=(DeletedMoveAssign&&) = default;
+};
+
+struct ImplicitlyDeletedMoveAssign {
+  DeletedMoveAssign X;
+};
+
+class MemberLvalueReference {
+public:
+  MemberLvalueReference(int&);
+
+private:
+  int& X;
+};
+
+class MemberRvalueReference {
+public:
+  MemberRvalueReference(int&&);
+
+private:
+  int&& X;
+};
+
+#endif // TEST_STD_CONCEPTS_LAND_MOVECONSTRUCTIBLE_H