adds equality for spaceship types for themselves

[cjdb]

Summary

• Adds operator==(partial_ordering, partial_ordering)
• Adds operator==(weak_ordering, weak_ordering)
• Adds operator==(strong_ordering, strong_ordering)

[miscco]

This looks obviously correct.

Thanks for working on this. I have one small nit regarding whether we need all combinations for the test but feel free to ignore it. More tests are generally better that fewer.

NOTE: I am not a maintainer so you should hold on merging this until a maintainer greenlights it. That said this seem close to the trivially correct clause

libcxx/include/compare

567

These are not part of the standard and should be handled by the rewriting of the equality operator. But definitely not part of your PR. Just raising awareness

libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp

164

I am wondering if we really need B != A if we already checked A != B on the library side.

Can we trust the compiler to have its own valid tests?

[cjdb]

Thanks @miscco! Hoping this lands very soon.

NOTE: I am not a maintainer so you should hold on merging this until a maintainer greenlights it. That said this seem close to the trivially correct clause

That won't be a problem, as I don't have write access. I'll need someone to merge it on my behalf please.

libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp

164

@CaseyCarter mentioned in my same_as patch that a lot of the MSVC STL type-traits tests tend to do the testing for the compiler, which is my motivation here. Also, since I expect these names to be ultimately user-defined, I wanted to be 100% sure that they're distinct.

I have no issues deleting them if you've got strong feelings :)

[EricWF]

libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp

164

I like tests. Let's keep them.

[cjdb]

Thanks @EricWF. Assuming your approval is synonymous with LGTM, is there anything actionable on my end before someone with write access commits it?

[ldionne]

Is there nothing in cxx2a_status.html that needs updating? We should also update the synopsis in <compare>.

What Author Name <email> do you want this committed as?

[cjdb]

Is there nothing in cxx2a_status.html that needs updating?

Done.

We should also update the synopsis in <compare>.

Done, possibly a bit overkill.

What Author Name <email> do you want this committed as?

Christopher Di Bella <[e-mail]> please.

[cjdb]

@ldionne is there anything that remains to be done on my end, or do I just need to sit tight for now?

libcxx/include/compare

template<class... Ts>
     using common_comparison_category_t = typename common_comparison_category<Ts...>::type;
 
   // [cmp.alg], comparison algorithms
   template<class T> constexpr strong_ordering strong_order(const T& a, const T& b);
   template<class T> constexpr weak_ordering weak_order(const T& a, const T& b);
   template<class T> constexpr partial_ordering partial_order(const T& a, const T& b);
   template<class T> constexpr strong_equality strong_equal(const T& a, const T& b);
   template<class T> constexpr weak_equality weak_equal(const T& a, const T& b);
+
+  // [cmp.partialord], Class partial_ordering
+  class partial_ordering {
+  public:
+    // valid values
+    static const partial_ordering less;
+    static const partial_ordering equivalent;
+    static const partial_ordering greater;
+    static const partial_ordering unordered;
+
+    // comparisons
+    friend constexpr bool operator==(partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator==(partial_ordering v, partial_ordering w) noexcept = default;
+    friend constexpr bool operator< (partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator> (partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator<=(partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator>=(partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator< (unspecified, partial_ordering v) noexcept;
+    friend constexpr bool operator> (unspecified, partial_ordering v) noexcept;
+    friend constexpr bool operator<=(unspecified, partial_ordering v) noexcept;
+    friend constexpr bool operator>=(unspecified, partial_ordering v) noexcept;
+    friend constexpr partial_ordering operator<=>(partial_ordering v, unspecified) noexcept;
+    friend constexpr partial_ordering operator<=>(unspecified, partial_ordering v) noexcept;
+  };
+
+  // [cmp.weakord], Class weak_ordering
+  class weak_ordering {
+  public:
+    // valid values
+    static const weak_ordering less;
+    static const weak_ordering equivalent;
+    static const weak_ordering greater;
+
+    // conversions
+    constexpr operator partial_ordering() const noexcept;
+
+    // comparisons
+    friend constexpr bool operator==(weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator==(weak_ordering v, weak_ordering w) noexcept = default;
+    friend constexpr bool operator< (weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator> (weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator<=(weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator>=(weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator< (unspecified, weak_ordering v) noexcept;
+    friend constexpr bool operator> (unspecified, weak_ordering v) noexcept;
+    friend constexpr bool operator<=(unspecified, weak_ordering v) noexcept;
+    friend constexpr bool operator>=(unspecified, weak_ordering v) noexcept;
+    friend constexpr weak_ordering operator<=>(weak_ordering v, unspecified) noexcept;
+    friend constexpr weak_ordering operator<=>(unspecified, weak_ordering v) noexcept;
+  };
+
+  // [cmp.strongord], Class strong_ordering
+  class strong_ordering {
+  public:
+    // valid values
+    static const strong_ordering less;
+    static const strong_ordering equal;
+    static const strong_ordering equivalent;
+    static const strong_ordering greater;
+
+    // conversions
+    constexpr operator partial_ordering() const noexcept;
+    constexpr operator weak_ordering() const noexcept;
+
+    // comparisons
+    friend constexpr bool operator==(strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator==(strong_ordering v, strong_ordering w) noexcept = default;
+    friend constexpr bool operator< (strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator> (strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator<=(strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator>=(strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator< (unspecified, strong_ordering v) noexcept;
+    friend constexpr bool operator> (unspecified, strong_ordering v) noexcept;
+    friend constexpr bool operator<=(unspecified, strong_ordering v) noexcept;
+    friend constexpr bool operator>=(unspecified, strong_ordering v) noexcept;
+    friend constexpr strong_ordering operator<=>(strong_ordering v, unspecified) noexcept;
+    friend constexpr strong_ordering operator<=>(unspecified, strong_ordering v) noexcept;
+  };
 }
 */
 
 #include <__config>
 #include <type_traits>
 #include <array>
 
 #ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
public:
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator==(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator!=(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator< (_CmpUnspecifiedParam, partial_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator<=(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator> (_CmpUnspecifiedParam, partial_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator>=(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
 
 #ifndef _LIBCPP_HAS_NO_SPACESHIP_OPERATOR
+  _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator==(partial_ordering, partial_ordering) noexcept = default;
+
   _LIBCPP_INLINE_VISIBILITY friend constexpr partial_ordering operator<=>(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr partial_ordering operator<=>(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
 #endif
 
 private:
   _ValueT __value_;
 };
 
public:
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator==(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator!=(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator< (_CmpUnspecifiedParam, weak_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator<=(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator> (_CmpUnspecifiedParam, weak_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator>=(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
 
 #ifndef _LIBCPP_HAS_NO_SPACESHIP_OPERATOR
+  _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator==(weak_ordering, weak_ordering) noexcept = default;
+
   _LIBCPP_INLINE_VISIBILITY friend constexpr weak_ordering operator<=>(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr weak_ordering operator<=>(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
 #endif
 
 private:
   _ValueT __value_;
 };
 
public:
 
   // comparisons
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator==(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator!=(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator< (strong_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator<=(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator> (strong_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator>=(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator==(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator!=(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator< (_CmpUnspecifiedParam, strong_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator<=(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator> (_CmpUnspecifiedParam, strong_ordering __v) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator>=(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
 
 #ifndef _LIBCPP_HAS_NO_SPACESHIP_OPERATOR
+  _LIBCPP_INLINE_VISIBILITY friend constexpr bool operator==(strong_ordering, strong_ordering) noexcept = default;
+
   _LIBCPP_INLINE_VISIBILITY friend constexpr strong_ordering operator<=>(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
   _LIBCPP_INLINE_VISIBILITY friend constexpr strong_ordering operator<=>(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
 #endif
 
 private:
   _ValueT __value_;
 };
 

libcxx/test/std/language.support/cmp/cmp.partialord/partialord.pass.cpp

case ER_Unord:
       assert(Res != 0);
       assert(0 != Res);
       assert((Res < 0) == false);
       assert((Res > 0) == false);
       assert((Res == 0) == false);
       break;
     }
   }
+  {
+    static_assert(std::partial_ordering::less == std::partial_ordering::less);
+    static_assert(std::partial_ordering::less !=
+                  std::partial_ordering::equivalent);
+    static_assert(std::partial_ordering::less !=
+                  std::partial_ordering::greater);
+    static_assert(std::partial_ordering::less !=
+                  std::partial_ordering::unordered);
+
+    static_assert(std::partial_ordering::equivalent !=
+                  std::partial_ordering::less);
+    static_assert(std::partial_ordering::equivalent ==
+                  std::partial_ordering::equivalent);
+    static_assert(std::partial_ordering::equivalent !=
+                  std::partial_ordering::greater);
+    static_assert(std::partial_ordering::equivalent !=
+                  std::partial_ordering::unordered);
+
+    static_assert(std::partial_ordering::greater !=
+                  std::partial_ordering::less);
+    static_assert(std::partial_ordering::greater !=
+                  std::partial_ordering::equivalent);
+    static_assert(std::partial_ordering::greater ==
+                  std::partial_ordering::greater);
+    static_assert(std::partial_ordering::greater !=
+                  std::partial_ordering::unordered);
+
+    static_assert(std::partial_ordering::unordered !=
+                  std::partial_ordering::less);
+    static_assert(std::partial_ordering::unordered !=
+                  std::partial_ordering::equivalent);
+    static_assert(std::partial_ordering::unordered !=
+                  std::partial_ordering::greater);
+    static_assert(std::partial_ordering::unordered ==
+                  std::partial_ordering::unordered);
+  }
 #endif
 
   return true;
 }
 
 int main(int, char**) {
   test_static_members();
   test_signatures();
   static_assert(test_conversion(), "conversion test failed");
   static_assert(test_constexpr(), "constexpr test failed");
 
   return 0;
 }

libcxx/test/std/language.support/cmp/cmp.strongord/strongord.pass.cpp

for (auto TC : SpaceshipTestCases)
     case ER_Less:
       assert(Res < 0);
       break;
     case ER_Greater:
       assert(Res > 0);
       break;
     }
   }
+  {
+    static_assert(std::strong_ordering::less == std::strong_ordering::less);
+    static_assert(std::strong_ordering::less != std::strong_ordering::equal);
+    static_assert(std::strong_ordering::less != std::strong_ordering::greater);
+
+    static_assert(std::strong_ordering::equal != std::strong_ordering::less);
+    static_assert(std::strong_ordering::equal == std::strong_ordering::equal);
+    static_assert(std::strong_ordering::equal != std::strong_ordering::greater);
+
+    static_assert(std::strong_ordering::greater != std::strong_ordering::less);
+    static_assert(std::strong_ordering::greater != std::strong_ordering::equal);
+    static_assert(std::strong_ordering::greater ==
+                  std::strong_ordering::greater);
+  }
 #endif
 
   return true;
 }
 
 int main(int, char**) {
   test_static_members();
   test_signatures();
   static_assert(test_conversion(), "conversion test failed");
   static_assert(test_constexpr(), "constexpr test failed");
 
   return 0;
 }

libcxx/test/std/language.support/cmp/cmp.weakord/weakord.pass.cpp

for (auto TC : SpaceshipTestCases)
     case ER_Less:
       assert(Res < 0);
       break;
     case ER_Greater:
       assert(Res > 0);
       break;
     }
   }
+
+  {
+    static_assert(std::weak_ordering::less == std::weak_ordering::less);
+    static_assert(std::weak_ordering::less != std::weak_ordering::equivalent);
+    static_assert(std::weak_ordering::less != std::weak_ordering::greater);
+
+    static_assert(std::weak_ordering::equivalent != std::weak_ordering::less);
+    static_assert(std::weak_ordering::equivalent ==
+                  std::weak_ordering::equivalent);
+    static_assert(std::weak_ordering::equivalent !=
+                  std::weak_ordering::greater);
+
+    static_assert(std::weak_ordering::greater != std::weak_ordering::less);
+    static_assert(std::weak_ordering::greater !=
+                  std::weak_ordering::equivalent);
+    static_assert(std::weak_ordering::greater == std::weak_ordering::greater);
+  }
 #endif
 
   return true;
 }
 
 int main(int, char**) {
   test_static_members();
   test_signatures();
   static_assert(test_conversion(), "conversion test failed");
   static_assert(test_constexpr(), "constexpr test failed");
 
   return 0;
 }

libcxx/www/cxx2a_status.html

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