1 files changed, 208 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-eq15.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-eq15.C
new file mode 100644
index 0000000..dc50956
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-eq15.C
@@ -0,0 +1,208 @@
+// P2468R2 - The Equality Operator You Are Looking For
+// { dg-do compile { target c++20 } }
+
+struct A {
+  bool operator== (const A &) { return true; }
+  bool operator!= (const A &) { return false; }
+};
+bool a = A{} != A{};
+
+template <typename T>
+struct B {
+  bool operator== (const T &) const;
+  bool operator!= (const T &) const;
+};
+struct B1 : B<B1> { };
+bool b1 = B1{} == B1{};
+bool b2 = B1{} != B1{};
+
+template <bool>
+struct C {
+  using C1 = C<true>;
+  using C2 = C<false>;
+  C () = default;
+  C (const C2 &);
+  bool operator== (C1) const;
+  bool operator!= (C1) const;
+};
+using C3 = C<false>;
+bool c = C3{} == C3{};
+
+struct D {
+  D ();
+  D (int *);
+  bool operator== (const D &) const;	// { dg-message "candidate: 'bool D::operator==\\\(const D&\\\) const' \\\(reversed\\\)" }
+  operator int * () const;
+};
+bool d = nullptr != D{};	// { dg-error "ambiguous overload for 'operator!=' in 'nullptr != D\\\(\\\)' \\\(operand types are 'std::nullptr_t' and 'D'\\\)" }
+				// { dg-message "candidate: 'operator!=\\\(int\\\*, int\\\*\\\)' \\\(built-in\\\)" "" { target *-*-* } .-1 }
+
+using ubool = unsigned char;
+
+struct E {
+  operator bool () const;
+};
+unsigned char operator== (E, E);// { dg-message "candidate: 'unsigned char operator==\\\(E, E\\\)'" }
+				// { dg-message "no known conversion for argument 1 from 'int' to 'E'" "" { target *-*-* } .-1 }
+unsigned char e = E{} != E{};	// { dg-error "return type of 'unsigned char operator==\\\(E, E\\\)' is not 'bool'" }
+				// { dg-message "used as rewritten candidate for comparison of 'E' and 'E'" "" { target *-*-* } .-1 }
+
+// F-H are the testcase from [over.match.oper]
+struct F {};
+template <typename T>
+bool operator== (F, T);		// { dg-message "candidate: 'template<class T> bool operator==\\\(F, T\\\)'" }
+				// { dg-message "template argument deduction/substitution failed:" "" { target *-*-* } .-1 }
+bool f1 = 0 == F ();		// OK, calls reversed ==
+template <typename T>
+bool operator!= (F, T);
+bool f2 = 0 == F ();		// { dg-error "no match for 'operator==' in '0 == F\\\(\\\)' \\\(operand types are 'int' and 'F'\\\)" }
+				// { dg-message "cannot convert '0' \\\(type 'int'\\\) to type 'F'" "" { target *-*-* } .-1 }
+
+struct G {
+  bool operator== (const G &);
+};
+struct G1 : G {
+  G1 ();
+  G1 (G);
+  bool operator!= (const G &);
+};
+bool g1 = G () == G1 ();	// OK, != prevents rewrite
+bool g2 = G1 () == G ();	// { dg-error "ambiguous, even though the second is reversed" }
+
+struct H {};
+template <typename T>
+bool operator== (H, T);
+inline namespace H1 {
+  template <typename T>
+  bool operator!= (H, T);
+}
+// [over.match.oper] currently says that this is OK because the inline
+// namespace isn't searched, but that seems wrong to me, so I'm going to go
+// ahead and search it for now.  Remove the "0 &&" in add_candidates to
+// change this to the currently specified behavior.
+// { dg-error "no match" "" { target *-*-* } .+1 }
+bool h = 0 == H ();		// OK, calls reversed ==
+
+template <class T>
+struct I {
+  int operator== (const double &) const;
+  friend inline int operator== (const double &, const T &) { return 1; }
+};
+struct I1 : I<I1> { };
+bool i = I1{} == 0.;		// { dg-error "return type of 'int operator==\\\(const double&, const I1&\\\)' is not 'bool'" }
+				// { dg-message "used as rewritten candidate for comparison of 'I1' and 'double'" "" { target *-*-* } .-1 }
+
+struct J {
+  bool operator== (const J &) const;
+  bool operator!= (const J &) const;
+};
+struct J1 : J {
+  J1 (const J &);
+  bool operator== (const J1 &x) const {
+    return static_cast<const J &> (*this) == x;	// { dg-error "ambiguous overload for 'operator==' in '\\\*\\\(const J\\\*\\\)\\\(\\\(const J1\\\*\\\)this\\\) == x' \\\(operand types are 'const J' and 'const J1'\\\)" }
+  }
+};
+
+struct K {
+  bool operator== (const K &);
+};
+bool k = K{} == K{};		// { dg-error "ambiguous, even though the second is reversed" }
+
+struct L {
+  bool operator== (const L &) const;
+};
+bool l = L{} == L{};
+
+struct M {
+  bool operator== (M);
+};
+bool m = M () == M ();
+
+struct N {
+  virtual bool operator== (const N &) const;
+};
+struct N1 : N {
+  bool operator== (const N &) const override;
+};
+bool n = N1 () == N1 ();	// { dg-error "ambiguous, even though the second is reversed" }
+
+struct O {
+  virtual signed char operator== (const O &) const;
+  signed char operator!= (const O &x) const { return !operator== (x); }
+};
+struct O1 : O {
+  signed char operator== (const O &) const override;
+};
+bool o = O1 () != O1 ();
+
+template <class T>
+bool
+foo (T x, T y)
+requires requires { x == y; }
+{
+  return x == y;
+}
+bool b3 = foo (B1 (), B1 ());
+
+struct P {};
+template <typename T, class U = int>
+bool operator== (P, T);
+template <class T>
+bool operator!= (P, T);
+bool p = 0 == P ();
+
+struct Q {};
+template <typename T>
+bool operator== (Q, T);
+template <typename U>
+bool operator!= (Q, U);
+bool q = 0 == Q ();		// { dg-error "" }
+
+struct R {
+  template <typename T>
+  bool operator== (const T &);
+};
+bool r = R () == R ();		// { dg-error "ambiguous, even though the second is reversed" }
+
+struct S {
+  template <typename T>
+  bool operator== (const T &) const;
+  bool operator!= (const S &);
+};
+bool s = S () == S ();
+
+struct T {};
+template <class U = int>
+bool operator== (T, int);
+bool operator!= (T, int);
+bool t = 0 == T ();
+
+struct U {};
+bool operator== (U, int);
+bool u1 = 0 == U ();
+namespace U1 { bool operator!= (U, int); }
+bool u2 = 0 == U ();
+using U1::operator!=;
+bool u3 = 0 == U ();		// { dg-error "" }
+
+struct V {};
+template <typename T>
+bool operator== (V, T);
+bool v1 = 0 == V ();
+namespace V1 { template <typename T> bool operator!= (V, T); }
+bool v2 = 0 == V ();
+using V1::operator!=;
+bool v3 = 0 == V ();		// { dg-error "" }
+
+template <int N>
+struct W {
+bool operator== (int) requires (N == 1);
+bool operator!= (int) requires (N == 2);
+};
+int w = 0 == W<1> ();
+
+struct X {
+  bool operator== (X const &);
+  static bool operator!= (X const &, X const &);	// { dg-error "'static bool X::operator!=\\\(const X&, const X&\\\)' must be either a non-static member function or a non-member function" }
+};
+bool x = X () == X ();		// { dg-error "ambiguous, even though the second is reversed" }