clang/test/SemaTemplate/operator-template.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s
   2
   3 // Make sure we accept this
   4 template<class X>struct A{typedef X Y;};
   5 template<class X>bool operator==(A<X>,typename A<X>::Y); // expected-note{{candidate template ignored: could not match 'A<X>' against 'B<int> *'}}
   6
   7 int a(A<int> x) { return operator==(x,1); }
   8
   9 int a0(A<int> x) { return x == 1; }
  10
  11 // FIXME: the location information for the note isn't very good
  12 template<class X>struct B{typedef X Y;};
  13 template<class X>bool operator==(B<X>*,typename B<X>::Y); // \
  14 // expected-error{{overloaded 'operator==' must have at least one parameter of class or enumeration type}} \
  15 // expected-note{{candidate template ignored: substitution failure [with X = int]}}
  16 int a(B<int> x) { return operator==(&x,1); } // expected-error{{no matching function for call to 'operator=='}} \
  17 // expected-note{{in instantiation of function template specialization}}
  18
  19 // Ensure we take parameter list reversal into account in partial oredring.
  20 namespace CompareOrdering {
  21   template<typename T> struct A {};
  22   template<typename T> int operator<=>(A<T>, int) = delete;
  23   template<typename T> int operator<=>(int, A<T*>);
  24   // OK, selects the more-specialized reversed function.
  25   bool b = A<int*>() < 0;
  26 }