[gcc r15-4337] libstdc++: Constrain std::expected comparisons (P3379R0)
Jonathan Wakely
redi@gcc.gnu.org
Mon Oct 14 15:50:13 GMT 2024
https://gcc.gnu.org/g:0515b2436b7c7e5e391eae7edc42173c52bab61d
commit r15-4337-g0515b2436b7c7e5e391eae7edc42173c52bab61d
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Wed Aug 28 12:01:18 2024 +0100
libstdc++: Constrain std::expected comparisons (P3379R0)
This proposal of mine has been approved by LEWG and forwarded to LWG. I
expect it to be voted into the draft without significant changes.
libstdc++-v3/ChangeLog:
* include/bits/version.def (constrained_equality): Bump value.
* include/bits/version.h: Regenerate.
* include/std/expected (operator==): Add constraints and
noexcept specifiers.
* testsuite/20_util/optional/relops/constrained.cc: Adjust
check for feature test macro.
* testsuite/20_util/pair/comparison_operators/constrained.cc:
Likewise.
* testsuite/20_util/tuple/comparison_operators/constrained.cc:
Likewise.
* testsuite/20_util/variant/relops/constrained.cc: Likewise.
* testsuite/20_util/expected/equality_constrained.cc: New test.
Diff:
---
libstdc++-v3/include/bits/version.def | 2 +-
libstdc++-v3/include/bits/version.h | 4 +-
libstdc++-v3/include/std/expected | 31 +++-
.../20_util/expected/equality_constrained.cc | 181 +++++++++++++++++++++
.../20_util/optional/relops/constrained.cc | 2 +-
.../pair/comparison_operators/constrained.cc | 2 +-
.../tuple/comparison_operators/constrained.cc | 2 +-
.../20_util/variant/relops/constrained.cc | 2 +-
8 files changed, 213 insertions(+), 13 deletions(-)
diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
index 477651f358a2..4fa820a5a4ab 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -1256,7 +1256,7 @@ ftms = {
ftms = {
name = constrained_equality;
values = {
- v = 202403;
+ v = 202411; // FIXME: 202403 for P2944R3, ??? for P3379R0
cxxmin = 20;
extra_cond = "__glibcxx_three_way_comparison";
};
diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
index 342ee6b4c7a0..fdbee8161d9e 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -1392,9 +1392,9 @@
#if !defined(__cpp_lib_constrained_equality)
# if (__cplusplus >= 202002L) && (__glibcxx_three_way_comparison)
-# define __glibcxx_constrained_equality 202403L
+# define __glibcxx_constrained_equality 202411L
# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constrained_equality)
-# define __cpp_lib_constrained_equality 202403L
+# define __cpp_lib_constrained_equality 202411L
# endif
# endif
#endif /* !defined(__cpp_lib_constrained_equality) && defined(__glibcxx_want_constrained_equality) */
diff --git a/libstdc++-v3/include/std/expected b/libstdc++-v3/include/std/expected
index d4a4bc175415..7de2aeffc70c 100644
--- a/libstdc++-v3/include/std/expected
+++ b/libstdc++-v3/include/std/expected
@@ -35,6 +35,7 @@
#define __glibcxx_want_expected
#define __glibcxx_want_freestanding_expected
+#define __glibcxx_want_constrained_equality
#include <bits/version.h>
#ifdef __cpp_lib_expected // C++ >= 23 && __cpp_concepts >= 202002L
@@ -1152,10 +1153,15 @@ namespace __expected
template<typename _Up, typename _Er2>
requires (!is_void_v<_Up>)
+ && requires (const _Tp& __t, const _Up& __u,
+ const _Er& __e, const _Er2& __e2) {
+ { __t == __u } -> convertible_to<bool>;
+ { __e == __e2 } -> convertible_to<bool>;
+ }
friend constexpr bool
operator==(const expected& __x, const expected<_Up, _Er2>& __y)
- // FIXME: noexcept(noexcept(bool(*__x == *__y))
- // && noexcept(bool(__x.error() == __y.error())))
+ noexcept(noexcept(bool(*__x == *__y))
+ && noexcept(bool(__x.error() == __y.error())))
{
if (__x.has_value())
return __y.has_value() && bool(*__x == *__y);
@@ -1164,15 +1170,22 @@ namespace __expected
}
template<typename _Up>
+ requires (!__expected::__is_expected<_Up>)
+ && requires (const _Tp& __t, const _Up& __u) {
+ { __t == __u } -> convertible_to<bool>;
+ }
friend constexpr bool
operator==(const expected& __x, const _Up& __v)
- // FIXME: noexcept(noexcept(bool(*__x == __v)))
+ noexcept(noexcept(bool(*__x == __v)))
{ return __x.has_value() && bool(*__x == __v); }
template<typename _Er2>
+ requires requires (const _Er& __e, const _Er2& __e2) {
+ { __e == __e2 } -> convertible_to<bool>;
+ }
friend constexpr bool
operator==(const expected& __x, const unexpected<_Er2>& __e)
- // FIXME: noexcept(noexcept(bool(__x.error() == __e.error())))
+ noexcept(noexcept(bool(__x.error() == __e.error())))
{ return !__x.has_value() && bool(__x.error() == __e.error()); }
friend constexpr void
@@ -1819,9 +1832,12 @@ namespace __expected
template<typename _Up, typename _Er2>
requires is_void_v<_Up>
+ && requires (const _Er& __e, const _Er2& __e2) {
+ { __e == __e2 } -> convertible_to<bool>;
+ }
friend constexpr bool
operator==(const expected& __x, const expected<_Up, _Er2>& __y)
- // FIXME: noexcept(noexcept(bool(__x.error() == __y.error())))
+ noexcept(noexcept(bool(__x.error() == __y.error())))
{
if (__x.has_value())
return __y.has_value();
@@ -1830,9 +1846,12 @@ namespace __expected
}
template<typename _Er2>
+ requires requires (const _Er& __e, const _Er2& __e2) {
+ { __e == __e2 } -> convertible_to<bool>;
+ }
friend constexpr bool
operator==(const expected& __x, const unexpected<_Er2>& __e)
- // FIXME: noexcept(noexcept(bool(__x.error() == __e.error())))
+ noexcept(noexcept(bool(__x.error() == __e.error())))
{ return !__x.has_value() && bool(__x.error() == __e.error()); }
friend constexpr void
diff --git a/libstdc++-v3/testsuite/20_util/expected/equality_constrained.cc b/libstdc++-v3/testsuite/20_util/expected/equality_constrained.cc
new file mode 100644
index 000000000000..7f6cefae7487
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/expected/equality_constrained.cc
@@ -0,0 +1,181 @@
+// { dg-do compile { target c++23 } }
+
+#include <expected>
+
+#ifndef __cpp_lib_constrained_equality
+# error "Feature-test macro for constrained_equality missing in <expected>"
+#elif __cpp_lib_constrained_equality < 202411L // TODO: use final value
+# error "Feature-test macro for constrained_equality has wrong value"
+#endif
+
+template<typename T, typename U = T, typename E = int, typename E2 = E>
+concept eq_comparable
+= requires (const std::expected<T, E>& t, const std::expected<U, E2>& u) {
+ t == u;
+};
+
+static_assert( eq_comparable<int> );
+static_assert( eq_comparable<int, long> );
+static_assert( eq_comparable<short, int> );
+static_assert( eq_comparable<int, long, unsigned int, unsigned long> );
+static_assert( eq_comparable<void, const void> );
+
+struct A { };
+static_assert( ! eq_comparable<A> );
+static_assert( ! eq_comparable<A, A> );
+static_assert( ! eq_comparable<A, int> );
+static_assert( ! eq_comparable<int, int, A> );
+static_assert( ! eq_comparable<int, int, int, A> );
+static_assert( ! eq_comparable<void, const void, A> );
+
+struct B { };
+void operator==(B, B);
+static_assert( ! eq_comparable<B> );
+static_assert( ! eq_comparable<B, B> );
+static_assert( ! eq_comparable<B, int> );
+static_assert( ! eq_comparable<int, int, B> );
+static_assert( ! eq_comparable<int, int, int, B> );
+static_assert( ! eq_comparable<void, void, B> );
+
+struct C { };
+bool operator==(C, C);
+static_assert( eq_comparable<C> );
+static_assert( eq_comparable<C, C> );
+static_assert( eq_comparable<C, C> );
+static_assert( eq_comparable<C, C, C> );
+static_assert( eq_comparable<int, int, C> );
+static_assert( ! eq_comparable<C, C, A, A> );
+static_assert( ! eq_comparable<C, C, A, int> );
+static_assert( eq_comparable<void, void, C> );
+
+struct D { };
+int operator==(D, D);
+bool operator!=(D, D) = delete;
+static_assert( eq_comparable<D> );
+static_assert( eq_comparable<D, D> );
+static_assert( eq_comparable<int, int, D> );
+static_assert( eq_comparable<D, D, D> );
+static_assert( ! eq_comparable<D, D, D, int> );
+
+struct E { };
+bool operator==(/* not-const */ E&, const E&);
+static_assert( ! eq_comparable<E> );
+static_assert( ! eq_comparable<E, E> );
+static_assert( ! eq_comparable<E, E> );
+static_assert( ! eq_comparable<int, int, E> );
+
+bool operator==(A, B);
+static_assert( eq_comparable<A, B> );
+static_assert( eq_comparable<B, A> );
+static_assert( eq_comparable<int, long, B, A> );
+
+int operator==(C, D);
+static_assert( eq_comparable<C, D> );
+static_assert( eq_comparable<D, C> );
+static_assert( eq_comparable<int, int, C, D> );
+static_assert( eq_comparable<int, int, D, C> );
+static_assert( eq_comparable<const void, void, C, D> );
+static_assert( eq_comparable<const void, void, D, C> );
+
+template<typename T, typename U = T, typename E = int>
+concept eq_comparable_val
+= requires (const std::expected<T, E>& t, const U& u) {
+ t == u;
+};
+
+static_assert( eq_comparable_val<int> );
+static_assert( eq_comparable_val<int, long> );
+static_assert( eq_comparable_val<short, int> );
+static_assert( eq_comparable_val<int, long, unsigned> );
+static_assert( ! eq_comparable_val<void, const void> );
+
+static_assert( ! eq_comparable_val<A> );
+static_assert( ! eq_comparable_val<A, A> );
+static_assert( ! eq_comparable_val<A, int> );
+static_assert( eq_comparable_val<int, int, A> );
+static_assert( ! eq_comparable_val<void, A> );
+
+static_assert( ! eq_comparable_val<B> );
+static_assert( ! eq_comparable_val<B, B> );
+static_assert( ! eq_comparable_val<B, int> );
+static_assert( eq_comparable_val<int, int, B> );
+static_assert( ! eq_comparable_val<void, B> );
+
+static_assert( eq_comparable_val<C> );
+static_assert( eq_comparable_val<C, C> );
+static_assert( eq_comparable_val<C, C> );
+static_assert( eq_comparable_val<C, C, C> );
+static_assert( eq_comparable_val<int, int, C> );
+static_assert( eq_comparable_val<C, C, A> );
+static_assert( ! eq_comparable_val<void, C> );
+
+static_assert( eq_comparable_val<D> );
+static_assert( eq_comparable_val<D, D> );
+static_assert( ! eq_comparable_val<D, int> );
+static_assert( eq_comparable_val<int, int, D> );
+static_assert( eq_comparable_val<D, D, D> );
+
+static_assert( ! eq_comparable_val<E> );
+static_assert( ! eq_comparable_val<E, E> );
+static_assert( ! eq_comparable_val<E, int> );
+static_assert( eq_comparable_val<int, int, E> );
+
+static_assert( eq_comparable_val<A, B> );
+static_assert( eq_comparable_val<B, A> );
+
+static_assert( eq_comparable_val<C, D> );
+static_assert( ! eq_comparable_val<D, C> );
+
+template<typename E, typename U, typename T = int>
+concept eq_comparable_unex
+= requires (const std::expected<T, E>& t, const std::unexpected<U>& u) {
+ t == u;
+};
+
+static_assert( eq_comparable_unex<int, int> );
+static_assert( eq_comparable_unex<int, long> );
+static_assert( eq_comparable_unex<short, int> );
+static_assert( eq_comparable_unex<int, int, void> );
+static_assert( eq_comparable_unex<int, long, void> );
+static_assert( eq_comparable_unex<short, int, void> );
+
+static_assert( ! eq_comparable_unex<A, A> );
+static_assert( ! eq_comparable_unex<A, int> );
+static_assert( ! eq_comparable_unex<int, A> );
+static_assert( ! eq_comparable_unex<A, A, void> );
+static_assert( ! eq_comparable_unex<A, int, void> );
+static_assert( ! eq_comparable_unex<int, A, void> );
+
+static_assert( ! eq_comparable_unex<B, B> );
+static_assert( ! eq_comparable_unex<B, int> );
+static_assert( ! eq_comparable_unex<int, B> );
+static_assert( ! eq_comparable_unex<B, B, void> );
+static_assert( ! eq_comparable_unex<B, int, void> );
+static_assert( ! eq_comparable_unex<int, B, void> );
+
+static_assert( eq_comparable_unex<C, C> );
+static_assert( eq_comparable_unex<C, C, void> );
+
+static_assert( eq_comparable_unex<D, D> );
+static_assert( ! eq_comparable_unex<D, int> );
+static_assert( ! eq_comparable_unex<int, D> );
+static_assert( eq_comparable_unex<D, D, void> );
+static_assert( ! eq_comparable_unex<D, int, void> );
+static_assert( ! eq_comparable_unex<int, D, void> );
+
+static_assert( ! eq_comparable_unex<E, E> );
+static_assert( ! eq_comparable_unex<E, int> );
+static_assert( ! eq_comparable_unex<int, E> );
+static_assert( ! eq_comparable_unex<E, E, void> );
+static_assert( ! eq_comparable_unex<E, int, void> );
+static_assert( ! eq_comparable_unex<int, E, void> );
+
+static_assert( eq_comparable_unex<A, B> );
+static_assert( eq_comparable_unex<B, A> );
+static_assert( eq_comparable_unex<A, B, void> );
+static_assert( eq_comparable_unex<B, A, void> );
+
+static_assert( eq_comparable_unex<C, D> );
+static_assert( ! eq_comparable_unex<D, C> );
+static_assert( eq_comparable_unex<C, D, void> );
+static_assert( ! eq_comparable_unex<D, C, void> );
diff --git a/libstdc++-v3/testsuite/20_util/optional/relops/constrained.cc b/libstdc++-v3/testsuite/20_util/optional/relops/constrained.cc
index 0e3256180084..3e3932579286 100644
--- a/libstdc++-v3/testsuite/20_util/optional/relops/constrained.cc
+++ b/libstdc++-v3/testsuite/20_util/optional/relops/constrained.cc
@@ -4,7 +4,7 @@
#ifndef __cpp_lib_constrained_equality
# error "Feature-test macro for constrained_equality missing"
-#elif __cpp_lib_constrained_equality != 202403
+#elif __cpp_lib_constrained_equality < 202403L
# error "Feature-test macro for constrained_equality has wrong value"
#endif
diff --git a/libstdc++-v3/testsuite/20_util/pair/comparison_operators/constrained.cc b/libstdc++-v3/testsuite/20_util/pair/comparison_operators/constrained.cc
index a35dbd265a78..dabe35ff7469 100644
--- a/libstdc++-v3/testsuite/20_util/pair/comparison_operators/constrained.cc
+++ b/libstdc++-v3/testsuite/20_util/pair/comparison_operators/constrained.cc
@@ -4,7 +4,7 @@
#ifndef __cpp_lib_constrained_equality
# error "Feature-test macro for constrained_equality missing"
-#elif __cpp_lib_constrained_equality != 202403
+#elif __cpp_lib_constrained_equality < 202403L
# error "Feature-test macro for constrained_equality has wrong value"
#endif
diff --git a/libstdc++-v3/testsuite/20_util/tuple/comparison_operators/constrained.cc b/libstdc++-v3/testsuite/20_util/tuple/comparison_operators/constrained.cc
index 47035ab18bab..994d4a491a1a 100644
--- a/libstdc++-v3/testsuite/20_util/tuple/comparison_operators/constrained.cc
+++ b/libstdc++-v3/testsuite/20_util/tuple/comparison_operators/constrained.cc
@@ -4,7 +4,7 @@
#ifndef __cpp_lib_constrained_equality
# error "Feature-test macro for constrained_equality missing"
-#elif __cpp_lib_constrained_equality != 202403
+#elif __cpp_lib_constrained_equality < 202403L
# error "Feature-test macro for constrained_equality has wrong value"
#endif
diff --git a/libstdc++-v3/testsuite/20_util/variant/relops/constrained.cc b/libstdc++-v3/testsuite/20_util/variant/relops/constrained.cc
index 95e8f754d1ed..fbe10e0ba03d 100644
--- a/libstdc++-v3/testsuite/20_util/variant/relops/constrained.cc
+++ b/libstdc++-v3/testsuite/20_util/variant/relops/constrained.cc
@@ -4,7 +4,7 @@
#ifndef __cpp_lib_constrained_equality
# error "Feature-test macro for constrained_equality missing"
-#elif __cpp_lib_constrained_equality != 202403
+#elif __cpp_lib_constrained_equality < 202403L
# error "Feature-test macro for constrained_equality has wrong value"
#endif
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