llvm-project/clang/test/SemaTemplate/operator-template.cpp

// RUN: %clang_cc1 -fsyntax-only -verify %s

// Make sure we accept this
template<class X>struct A{typedef X Y;};
template<class X>bool operator==(A<X>,typename A<X>::Y); // expected-note{{candidate template ignored: could not match 'A<type-parameter-0-0>' against 'B<int> *'}}

int a(A<int> x) { return operator==(x,1); }

int a0(A<int> x) { return x == 1; }

// FIXME: the location information for the note isn't very good
template<class X>struct B{typedef X Y;};
template<class X>bool operator==(B<X>*,typename B<X>::Y); // \
// expected-error{{overloaded 'operator==' must have at least one parameter of class or enumeration type}} \
// expected-note{{candidate template ignored: substitution failure [with X = int]}}
int a(B<int> x) { return operator==(&x,1); } // expected-error{{no matching function for call to 'operator=='}} \
// expected-note{{in instantiation of function template specialization}}