1 files changed, 38 insertions, 0 deletions
diff --git a/test/CXX/over/over.match/over.match.funcs/over.match.oper/p9-2a.cpp b/test/CXX/over/over.match/over.match.funcs/over.match.oper/p9-2a.cpp
new file mode 100644
index 0000000000..fce46816ce
--- /dev/null
+++ b/test/CXX/over/over.match/over.match.funcs/over.match.oper/p9-2a.cpp
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -std=c++2a -verify %s
+
+// ... return type shall be cv bool ...
+namespace not_bool {
+  struct X {} x;
+  struct Y {} y;
+  int operator==(X, Y); // expected-note 4{{here}}
+  bool a = x == y; // ok
+  bool b = y == x; // expected-error {{return type 'int' of selected 'operator==' function for rewritten '==' comparison is not 'bool'}}
+  bool c = x != y; // expected-error {{return type 'int' of selected 'operator==' function for rewritten '!=' comparison is not 'bool'}}
+  bool d = y != x; // expected-error {{return type 'int' of selected 'operator==' function for rewritten '!=' comparison is not 'bool'}}
+
+  // cv-qualifiers are OK
+  const bool operator==(Y, X);
+  bool e = y != x; // ok
+
+  // We don't prefer a function with bool return type over one witn non-bool return type.
+  bool f = x != y; // expected-error {{return type 'int' of selected 'operator==' function for rewritten '!=' comparison is not 'bool'}}
+}
+
+struct X { bool equal; };
+struct Y {};
+constexpr bool operator==(X x, Y) { return x.equal; }
+
+static_assert(X{true} == Y{});
+static_assert(X{false} == Y{}); // expected-error {{failed}}
+
+// x == y -> y == x
+static_assert(Y{} == X{true});
+static_assert(Y{} == X{false}); // expected-error {{failed}}
+
+// x != y -> !(x == y)
+static_assert(X{true} != Y{}); // expected-error {{failed}}
+static_assert(X{false} != Y{});
+
+// x != y -> !(y == x)
+static_assert(Y{} != X{true}); // expected-error {{failed}}
+static_assert(Y{} != X{false});