clang/test/SemaCXX/warn-zero-nullptr-cxx20.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s -Wzero-as-null-pointer-constant -std=c++20
   2
   3 namespace std {
   4 class strong_ordering;
   5
   6 // Mock how STD defined unspecified parameters for the operators below.
   7 struct _CmpUnspecifiedParam {
   8   consteval
   9   _CmpUnspecifiedParam(int _CmpUnspecifiedParam::*) noexcept {}
  10 };
  11
  12 struct strong_ordering {
  13   signed char value;
  14
  15   friend constexpr bool operator==(strong_ordering v,
  16                                    _CmpUnspecifiedParam) noexcept {
  17     return v.value == 0;
  18   }
  19   friend constexpr bool operator<(strong_ordering v,
  20                                   _CmpUnspecifiedParam) noexcept {
  21     return v.value < 0;
  22   }
  23   friend constexpr bool operator>(strong_ordering v,
  24                                   _CmpUnspecifiedParam) noexcept {
  25     return v.value > 0;
  26   }
  27   friend constexpr bool operator>=(strong_ordering v,
  28                                    _CmpUnspecifiedParam) noexcept {
  29     return v.value >= 0;
  30   }
  31   static const strong_ordering equal, greater, less;
  32 };
  33 constexpr strong_ordering strong_ordering::equal = {0};
  34 constexpr strong_ordering strong_ordering::greater = {1};
  35 constexpr strong_ordering strong_ordering::less = {-1};
  36 } // namespace std
  37
  38 struct A {
  39   int a;
  40   constexpr auto operator<=>(const A &other) const = default;
  41 };
  42
  43 void test_cxx_rewritten_binary_ops() {
  44   A a1, a2;
  45   bool result;
  46   result = (a1 < a2);
  47   result = (a1 >= a2);
  48   int *ptr = 0; // expected-warning{{zero as null pointer constant}}
  49   result = (a1 > (ptr == 0 ? a1 : a2)); // expected-warning{{zero as null pointer constant}}
  50   result = (a1 > ((a1 > (ptr == 0 ? a1 : a2)) ? a1 : a2)); // expected-warning{{zero as null pointer constant}}
  51 }