--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/SemaCXX/overloaded-operator-decl.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,60 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s 
+struct X { 
+  X();
+  X(int); 
+};
+
+X operator+(X, X);
+X operator-(X, X) { X x; return x; }
+
+struct Y {
+  Y operator-() const;
+  void operator()(int x = 17) const;
+  int operator[](int);
+
+  static int operator+(Y, Y); // expected-error{{overloaded 'operator+' cannot be a static member function}}
+};
+
+
+void f(X x) {
+  x = operator+(x, x);
+}
+
+X operator+(int, float); // expected-error{{overloaded 'operator+' must have at least one parameter of class or enumeration type}}
+
+X operator*(X, X = 5); // expected-error{{parameter of overloaded 'operator*' cannot have a default argument}}
+
+X operator/(X, X, ...); // expected-error{{overloaded 'operator/' cannot be variadic}}
+
+X operator%(Y); // expected-error{{overloaded 'operator%' must be a binary operator (has 1 parameter)}}
+
+void operator()(Y&, int, int); // expected-error{{overloaded 'operator()' must be a non-static member function}}
+
+typedef int INT;
+typedef float FLOAT;
+Y& operator++(Y&);
+Y operator++(Y&, INT);
+X operator++(X&, FLOAT); // expected-error{{parameter of overloaded post-increment operator must have type 'int' (not 'FLOAT' (aka 'float'))}}
+
+int operator+; // expected-error{{'operator+' cannot be the name of a variable or data member}}
+
+namespace PR6238 {
+  static struct {
+    void operator()();
+  } plus;
+}
+
+struct PR10839 {
+  operator int; // expected-error{{'operator int' cannot be the name of a variable or data member}}
+  int operator+; // expected-error{{'operator+' cannot be the name of a variable or data member}}
+};
+
+namespace PR14120 {
+  struct A {
+    static void operator()(int& i) { ++i; } // expected-error{{overloaded 'operator()' cannot be a static member function}}
+  };
+  void f() {
+    int i = 0;
+    A()(i);
+  }
+}