class X { public: friend X& operator+=(X& x, const X& y); }; X& operator+=(X& x, const X& y) { return x; } int main() { X() += X(); }
Standard input is empty
prog.cpp: In function 'int main()': prog.cpp:11:12: error: no match for 'operator+=' in 'X() += X()' prog.cpp:7:4: note: candidate is: X& operator+=(X&, const X&)
Standard output is empty