[libcxx-commits] [libcxx] [libc++] P3379R1: Constrain `std::expected` equality operators (PR #117664)
Xiaoyang Liu via libcxx-commits
libcxx-commits at lists.llvm.org
Sat Nov 30 18:11:54 PST 2024
https://github.com/xiaoyang-sde updated https://github.com/llvm/llvm-project/pull/117664
>From 002fcac983085257ad28dfa9b45d8a7493e7dccc Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Mon, 25 Nov 2024 23:26:19 -0500
Subject: [PATCH 1/4] [libc++] P3379R1: Constrain 'std::expected' equality
operators
---
libcxx/include/__expected/expected.h | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/libcxx/include/__expected/expected.h b/libcxx/include/__expected/expected.h
index 3d3f11967ee746..7dc0248fcd72f9 100644
--- a/libcxx/include/__expected/expected.h
+++ b/libcxx/include/__expected/expected.h
@@ -10,6 +10,7 @@
#define _LIBCPP___EXPECTED_EXPECTED_H
#include <__assert>
+#include <__concepts/convertible_to.h>
#include <__config>
#include <__expected/bad_expected_access.h>
#include <__expected/unexpect.h>
@@ -1139,7 +1140,11 @@ class expected : private __expected_base<_Tp, _Err> {
// [expected.object.eq], equality operators
template <class _T2, class _E2>
- requires(!is_void_v<_T2>)
+ requires(!is_void_v<_T2> &&
+ requires(const _Tp& __tp, const _T2& __t2, const _Err& __err, const _E2& __e2) {
+ { __tp == __t2 } -> convertible_to<bool>;
+ { __err == __e2 } -> convertible_to<bool>;
+ })
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const expected<_T2, _E2>& __y) {
if (__x.__has_val() != __y.__has_val()) {
return false;
@@ -1153,11 +1158,18 @@ class expected : private __expected_base<_Tp, _Err> {
}
template <class _T2>
+ requires(!__is_std_expected<_T2>::value &&
+ requires(const _Tp& __tp, const _T2& __t2) {
+ { __tp == __t2 } -> convertible_to<bool>;
+ })
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const _T2& __v) {
return __x.__has_val() && static_cast<bool>(__x.__val() == __v);
}
template <class _E2>
+ requires requires(const _Err& __err, const _E2& __e2) {
+ { __err == __e2 } -> convertible_to<bool>;
+ }
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const unexpected<_E2>& __e) {
return !__x.__has_val() && static_cast<bool>(__x.__unex() == __e.error());
}
@@ -1850,7 +1862,10 @@ class expected<_Tp, _Err> : private __expected_void_base<_Err> {
// [expected.void.eq], equality operators
template <class _T2, class _E2>
- requires is_void_v<_T2>
+ requires(is_void_v<_T2> &&
+ requires(const _Err& __err, const _E2& __e2) {
+ { __err == __e2 } -> convertible_to<bool>;
+ })
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const expected<_T2, _E2>& __y) {
if (__x.__has_val() != __y.__has_val()) {
return false;
@@ -1860,6 +1875,9 @@ class expected<_Tp, _Err> : private __expected_void_base<_Err> {
}
template <class _E2>
+ requires requires(const _Err& __err, const _E2& __e2) {
+ { __err == __e2 } -> convertible_to<bool>;
+ }
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const unexpected<_E2>& __y) {
return !__x.__has_val() && static_cast<bool>(__x.__unex() == __y.error());
}
>From 408b3315450bf97e4b1c0e23f37dc9462c71578b Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Thu, 28 Nov 2024 01:16:30 -0500
Subject: [PATCH 2/4] [libc++] P3379R1: Constrain 'std::expected' equality
operators
---
libcxx/include/__expected/expected.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/libcxx/include/__expected/expected.h b/libcxx/include/__expected/expected.h
index 7dc0248fcd72f9..ca9dcfb1569e8b 100644
--- a/libcxx/include/__expected/expected.h
+++ b/libcxx/include/__expected/expected.h
@@ -1140,11 +1140,15 @@ class expected : private __expected_base<_Tp, _Err> {
// [expected.object.eq], equality operators
template <class _T2, class _E2>
+# if _LIBCPP_STD_VER >= 26
requires(!is_void_v<_T2> &&
requires(const _Tp& __tp, const _T2& __t2, const _Err& __err, const _E2& __e2) {
{ __tp == __t2 } -> convertible_to<bool>;
{ __err == __e2 } -> convertible_to<bool>;
})
+# else
+ requires(!is_void_v<_T2>)
+# endif
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const expected<_T2, _E2>& __y) {
if (__x.__has_val() != __y.__has_val()) {
return false;
@@ -1158,18 +1162,22 @@ class expected : private __expected_base<_Tp, _Err> {
}
template <class _T2>
+# if _LIBCPP_STD_VER >= 26
requires(!__is_std_expected<_T2>::value &&
requires(const _Tp& __tp, const _T2& __t2) {
{ __tp == __t2 } -> convertible_to<bool>;
})
+# endif
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const _T2& __v) {
return __x.__has_val() && static_cast<bool>(__x.__val() == __v);
}
template <class _E2>
+# if _LIBCPP_STD_VER >= 26
requires requires(const _Err& __err, const _E2& __e2) {
{ __err == __e2 } -> convertible_to<bool>;
}
+# endif
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const unexpected<_E2>& __e) {
return !__x.__has_val() && static_cast<bool>(__x.__unex() == __e.error());
}
@@ -1862,10 +1870,14 @@ class expected<_Tp, _Err> : private __expected_void_base<_Err> {
// [expected.void.eq], equality operators
template <class _T2, class _E2>
+# if _LIBCPP_STD_VER >= 26
requires(is_void_v<_T2> &&
requires(const _Err& __err, const _E2& __e2) {
{ __err == __e2 } -> convertible_to<bool>;
})
+# else
+ requires is_void_v<_T2>
+# endif
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const expected<_T2, _E2>& __y) {
if (__x.__has_val() != __y.__has_val()) {
return false;
@@ -1875,9 +1887,11 @@ class expected<_Tp, _Err> : private __expected_void_base<_Err> {
}
template <class _E2>
+# if _LIBCPP_STD_VER >= 26
requires requires(const _Err& __err, const _E2& __e2) {
{ __err == __e2 } -> convertible_to<bool>;
}
+# endif
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const expected& __x, const unexpected<_E2>& __y) {
return !__x.__has_val() && static_cast<bool>(__x.__unex() == __y.error());
}
>From 6d540b6305757133c777a1a768d06e6b4abcc9a8 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Sat, 30 Nov 2024 20:51:37 -0500
Subject: [PATCH 3/4] [libc++] P3379R1: Constrain 'std::expected' equality
operators
---
.../expected.void/equality/equality.other_expected.pass.cpp | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/libcxx/test/std/utilities/expected/expected.void/equality/equality.other_expected.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/equality/equality.other_expected.pass.cpp
index 8b24875586852f..5de9d9b34f0aa0 100644
--- a/libcxx/test/std/utilities/expected/expected.void/equality/equality.other_expected.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/equality/equality.other_expected.pass.cpp
@@ -23,15 +23,12 @@
template <class T1, class T2>
concept CanCompare = requires(T1 t1, T2 t2) { t1 == t2; };
-struct Foo{};
+struct Foo {};
static_assert(!CanCompare<Foo, Foo>);
static_assert(CanCompare<std::expected<void, int>, std::expected<void, int>>);
static_assert(CanCompare<std::expected<void, int>, std::expected<void, short>>);
-// Note this is true because other overloads in expected<non-void> are unconstrained
-static_assert(CanCompare<std::expected<void, int>, std::expected<int, int>>);
-
constexpr bool test() {
// x.has_value() && y.has_value()
{
>From 02d1d91bbc52c1059305f7c42a93641b012ed318 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Sat, 30 Nov 2024 21:11:37 -0500
Subject: [PATCH 4/4] [libc++] P3379R1: Constrain 'std::expected' equality
operators
---
libcxx/docs/ReleaseNotes/20.rst | 1 +
.../equality/equality.other_expected.pass.cpp | 5 +----
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/libcxx/docs/ReleaseNotes/20.rst b/libcxx/docs/ReleaseNotes/20.rst
index d520c46bae1ef1..0c69e76560755d 100644
--- a/libcxx/docs/ReleaseNotes/20.rst
+++ b/libcxx/docs/ReleaseNotes/20.rst
@@ -45,6 +45,7 @@ Implemented Papers
- ``std::jthread`` and ``<stop_token>`` are not guarded behind ``-fexperimental-library`` anymore
- P2674R1: A trait for implicit lifetime types (`Github <https://github.com/llvm/llvm-project/issues/105259>`__)
- P0429R9: A Standard ``flat_map`` is partially implemented and ``flat_map`` is provided (`Github <https://github.com/llvm/llvm-project/issues/105190>`__)
+- P3379R1: Constrain ``std::expected`` equality operators
Improvements and New Features
-----------------------------
diff --git a/libcxx/test/std/utilities/expected/expected.expected/equality/equality.other_expected.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/equality/equality.other_expected.pass.cpp
index 9325c6c61ad2db..58789f6c421d10 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/equality/equality.other_expected.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/equality/equality.other_expected.pass.cpp
@@ -23,15 +23,12 @@
template <class T1, class T2>
concept CanCompare = requires(T1 t1, T2 t2) { t1 == t2; };
-struct Foo{};
+struct Foo {};
static_assert(!CanCompare<Foo, Foo>);
static_assert(CanCompare<std::expected<int, int>, std::expected<int, int>>);
static_assert(CanCompare<std::expected<int, int>, std::expected<short, short>>);
-// Note this is true because other overloads are unconstrained
-static_assert(CanCompare<std::expected<int, int>, std::expected<void, int>>);
-
constexpr bool test() {
// x.has_value() && y.has_value()
{
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