feature/spaceship: Clause 26: Numerics

stl/inc/complex

@@ -1514,12 +1514,15 @@ _NODISCARD constexpr bool operator==(const complex<_Ty>& _Left, const _Ty& _Righ
     return _Left.real() == _Right && _Left.imag() == 0;
 }
 
+#if !_HAS_CXX20
 template <class _Ty>
 _NODISCARD constexpr bool operator==(const _Ty& _Left, const complex<_Ty>& _Right) {
     return _Left == _Right.real() && 0 == _Right.imag();
 }
+#endif //!_HAS_CXX20
 
 // FUNCTION TEMPLATE operator!=
+#if !_HAS_CXX20
 template <class _Ty>
 _NODISCARD constexpr bool operator!=(const complex<_Ty>& _Left, const complex<_Ty>& _Right) {
     return !(_Left == _Right);
@@ -1534,6 +1537,7 @@ template <class _Ty>
 _NODISCARD constexpr bool operator!=(const _Ty& _Left, const complex<_Ty>& _Right) {
     return !(_Left == _Right);
 }
+#endif //!_HAS_CXX20
 
 // FUNCTION TEMPLATE imag
 template <class _Ty>

stl/inc/valarray

@@ -1372,6 +1372,11 @@ public:
     _NODISCARD size_t stride() const noexcept /* strengthened */ {
         return _Stride;
     }
+#if _HAS_CXX200
+    friend bool operator==(const slice& x, const slice& y) {
+        return x.start() == y.start() && x.size() == y.size() && x.stride() == y.stride();
+    }
+#endif
 
 protected:
     size_t _Start  = 0; // the starting offset

tests/std/tests/P1614R2_spaceship/test.cpp

@@ -15,6 +15,7 @@
 #include <iostream>
 #include <list>
 #include <map>
+#include <numeric>
 #include <queue>
 #include <ranges>
 #include <regex>
@@ -27,6 +28,7 @@
 #include <unordered_map>
 #include <unordered_set>
 #include <utility>
+#include <valarray>
 #include <vector>
 
 template <class T>
@@ -287,6 +289,23 @@ void ordering_test_cases() {
         std::forward_list<SynthOrdered> b = {10, 20, 40};
         ordered_containers_test(a, a, b);
     }
+    { // slice
+        std::valarray<int> a(20);
+        for (int i = 0; i < 12; ++i) {
+            a[i] = i;
+        }
+
+        const auto a1 = a[std::slice(2, 3, 4)];
+        const auto a2 = a[std::slice(2, 3, 4)];
+        const auto a3 = a[std::slice(3, 3, 4)];
+        const auto a4 = a[std::slice(2, 4, 4)];
+        const auto a5 = a[std::slice(2, 3, 3)];
+
+        static_assert((a1 == a2) == true);
+        static_assert((a1 == a3) == false);
+        static_assert((a1 == a4) == false);
+        static_assert((a1 == a5) == false);
+    }
     { // map
         std::map<std::string, int> a1;
         a1["hi"]   = 1;