[libc++][NFC] Refactored equality comparisons tests for pair and expected (llvm#145668)

Refactored `std::expected` and `std::pair` tests to use the
canonicalized names from `test_comparisions.h`, which are shared between
tests.

This was split from llvm#139368 as
per comment
llvm#139368 (review)

Towards implementing [P2944R3: Comparisons for
reference_wrapper](llvm#105424)

---------

Co-authored-by: Hristo Hristov <zingam@outlook.com>
Co-authored-by: Nikolas Klauser <nikolasklauser@berlin.de>

Author: 3 people

libcxx/test/std/utilities/expected/expected.expected/equality/equality.T2.pass.cpp

@@ -16,14 +16,14 @@
 #include <type_traits>
 #include <utility>
 
+#include "test_comparisons.h"
 #include "test_macros.h"
-#include "../../types.h"
 
 #if TEST_STD_VER >= 26
 // https://wg21.link/P3379R0
-static_assert(CanCompare<std::expected<int, int>, int>);
-static_assert(CanCompare<std::expected<int, int>, EqualityComparable>);
-static_assert(!CanCompare<std::expected<int, int>, NonComparable>);
+static_assert(HasOperatorEqual<std::expected<int, int>, int>);
+static_assert(HasOperatorEqual<std::expected<int, int>, EqualityComparable>);
+static_assert(!HasOperatorEqual<std::expected<int, int>, NonComparable>);
 #endif
 
 constexpr bool test() {

libcxx/test/std/utilities/expected/expected.expected/equality/equality.other_expected.pass.cpp

@@ -17,26 +17,26 @@
 #include <type_traits>
 #include <utility>
 
+#include "test_comparisons.h"
 #include "test_macros.h"
-#include "../../types.h"
 
 // Test constraint
-static_assert(!CanCompare<NonComparable, NonComparable>);
+static_assert(!HasOperatorEqual<NonComparable, NonComparable>);
 
-static_assert(CanCompare<std::expected<int, int>, std::expected<int, int>>);
-static_assert(CanCompare<std::expected<int, int>, std::expected<short, short>>);
+static_assert(HasOperatorEqual<std::expected<int, int>, std::expected<int, int>>);
+static_assert(HasOperatorEqual<std::expected<int, int>, std::expected<short, short>>);
 
 #if TEST_STD_VER >= 26
 // https://wg21.link/P3379R0
-static_assert(!CanCompare<std::expected<int, int>, std::expected<void, int>>);
-static_assert(CanCompare<std::expected<int, int>, std::expected<int, int>>);
-static_assert(!CanCompare<std::expected<NonComparable, int>, std::expected<NonComparable, int>>);
-static_assert(!CanCompare<std::expected<int, NonComparable>, std::expected<int, NonComparable>>);
-static_assert(!CanCompare<std::expected<NonComparable, int>, std::expected<int, NonComparable>>);
-static_assert(!CanCompare<std::expected<int, NonComparable>, std::expected<NonComparable, int>>);
+static_assert(!HasOperatorEqual<std::expected<int, int>, std::expected<void, int>>);
+static_assert(HasOperatorEqual<std::expected<int, int>, std::expected<int, int>>);
+static_assert(!HasOperatorEqual<std::expected<NonComparable, int>, std::expected<NonComparable, int>>);
+static_assert(!HasOperatorEqual<std::expected<int, NonComparable>, std::expected<int, NonComparable>>);
+static_assert(!HasOperatorEqual<std::expected<NonComparable, int>, std::expected<int, NonComparable>>);
+static_assert(!HasOperatorEqual<std::expected<int, NonComparable>, std::expected<NonComparable, int>>);
 #else
 // Note this is true because other overloads in expected<non-void> are unconstrained
-static_assert(CanCompare<std::expected<void, int>, std::expected<int, int>>);
+static_assert(HasOperatorEqual<std::expected<void, int>, std::expected<int, int>>);
 #endif
 constexpr bool test() {
   // x.has_value() && y.has_value()

libcxx/test/std/utilities/expected/expected.expected/equality/equality.unexpected.pass.cpp

@@ -16,14 +16,14 @@
 #include <type_traits>
 #include <utility>
 
+#include "test_comparisons.h"
 #include "test_macros.h"
-#include "../../types.h"
 
 #if TEST_STD_VER >= 26
 // https://wg21.link/P3379R0
-static_assert(CanCompare<std::expected<EqualityComparable, EqualityComparable>, std::unexpected<int>>);
-static_assert(CanCompare<std::expected<EqualityComparable, int>, std::unexpected<EqualityComparable>>);
-static_assert(!CanCompare<std::expected<EqualityComparable, NonComparable>, std::unexpected<int>>);
+static_assert(HasOperatorEqual<std::expected<EqualityComparable, EqualityComparable>, std::unexpected<int>>);
+static_assert(HasOperatorEqual<std::expected<EqualityComparable, int>, std::unexpected<EqualityComparable>>);
+static_assert(!HasOperatorEqual<std::expected<EqualityComparable, NonComparable>, std::unexpected<int>>);
 #endif
 
 constexpr bool test() {

libcxx/test/std/utilities/expected/expected.void/equality/equality.other_expected.pass.cpp

@@ -17,26 +17,26 @@
 #include <type_traits>
 #include <utility>
 
+#include "test_comparisons.h"
 #include "test_macros.h"
-#include "../../types.h"
 
 struct Foo{};
-static_assert(!CanCompare<Foo, Foo>);
+static_assert(!HasOperatorEqual<Foo, Foo>);
 
-static_assert(CanCompare<std::expected<void, int>, std::expected<void, int>>);
-static_assert(CanCompare<std::expected<void, int>, std::expected<void, short>>);
+static_assert(HasOperatorEqual<std::expected<void, int>, std::expected<void, int>>);
+static_assert(HasOperatorEqual<std::expected<void, int>, std::expected<void, short>>);
 
 #if TEST_STD_VER >= 26
 // https://wg21.link/P3379R0
-static_assert(!CanCompare<std::expected<void, int>, std::expected<int, int>>);
-static_assert(CanCompare<std::expected<void, int>, std::expected<void, int>>);
-static_assert(CanCompare<std::expected<void, int>, std::expected<void, int>>);
-static_assert(!CanCompare<std::expected<void, NonComparable>, std::expected<void, NonComparable>>);
-static_assert(!CanCompare<std::expected<void, int>, std::expected<void, NonComparable>>);
-static_assert(!CanCompare<std::expected<void, NonComparable>, std::expected<void, int>>);
+static_assert(!HasOperatorEqual<std::expected<void, int>, std::expected<int, int>>);
+static_assert(HasOperatorEqual<std::expected<void, int>, std::expected<void, int>>);
+static_assert(HasOperatorEqual<std::expected<void, int>, std::expected<void, int>>);
+static_assert(!HasOperatorEqual<std::expected<void, NonComparable>, std::expected<void, NonComparable>>);
+static_assert(!HasOperatorEqual<std::expected<void, int>, std::expected<void, NonComparable>>);
+static_assert(!HasOperatorEqual<std::expected<void, NonComparable>, std::expected<void, int>>);
 #else
 // Note this is true because other overloads in expected<non-void> are unconstrained
-static_assert(CanCompare<std::expected<void, int>, std::expected<int, int>>);
+static_assert(HasOperatorEqual<std::expected<void, int>, std::expected<int, int>>);
 #endif
 
 constexpr bool test() {

libcxx/test/std/utilities/expected/expected.void/equality/equality.unexpected.pass.cpp

@@ -16,14 +16,14 @@
 #include <type_traits>
 #include <utility>
 
+#include "test_comparisons.h"
 #include "test_macros.h"
-#include "../../types.h"
 
 #if TEST_STD_VER >= 26
 // https://wg21.link/P3379R0
-static_assert(CanCompare<std::expected<void, EqualityComparable>, std::unexpected<int>>);
-static_assert(CanCompare<std::expected<void, int>, std::unexpected<EqualityComparable>>);
-static_assert(!CanCompare<std::expected<void, NonComparable>, std::unexpected<int>>);
+static_assert(HasOperatorEqual<std::expected<void, EqualityComparable>, std::unexpected<int>>);
+static_assert(HasOperatorEqual<std::expected<void, int>, std::unexpected<EqualityComparable>>);
+static_assert(!HasOperatorEqual<std::expected<void, NonComparable>, std::unexpected<int>>);
 #endif
 
 constexpr bool test() {

libcxx/test/std/utilities/expected/types.h

@@ -336,17 +336,4 @@ struct CheckForInvalidWrites : public CheckForInvalidWritesBase<WithPaddedExpect
   }
 };
 
-struct NonComparable {};
-
-struct EqualityComparable {
-  int i;
-  constexpr EqualityComparable(int ii) : i(ii) {}
-
-  friend constexpr bool operator==(const EqualityComparable& data, int ii) { return data.i == ii; }
-};
-
-// Test constraint
-template <class T1, class T2>
-concept CanCompare = requires(T1 t1, T2 t2) { t1 == t2; };
-
 #endif // TEST_STD_UTILITIES_EXPECTED_TYPES_H

libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp

@@ -21,28 +21,15 @@
 #include <cassert>
 #include <concepts>
 
+#include "test_comparisons.h"
 #include "test_macros.h"
 
 #if TEST_STD_VER >= 26
 
 // Test SFINAE.
 
-struct EqualityComparable {
-  constexpr EqualityComparable(int value) : value_{value} {};
-
-  friend constexpr bool operator==(const EqualityComparable&, const EqualityComparable&) noexcept = default;
-
-  int value_;
-};
-
-static_assert(std::equality_comparable<EqualityComparable>);
-
 static_assert(std::equality_comparable<std::pair<EqualityComparable, EqualityComparable>>);
 
-struct NonComparable {};
-
-static_assert(!std::equality_comparable<NonComparable>);
-
 static_assert(!std::equality_comparable<std::pair<EqualityComparable, NonComparable>>);
 static_assert(!std::equality_comparable<std::pair<NonComparable, EqualityComparable>>);