clang/test/SemaTemplate/ms-if-exists.cpp

   1 // RUN: %clang_cc1 -fms-extensions -std=c++11 %s -verify
   2
   3 struct Nontemplate {
   4   typedef int type;
   5 };
   6
   7 template<typename T>
   8 struct X {
   9   __if_exists(Nontemplate::type) {
  10     typedef Nontemplate::type type;
  11   }
  12
  13   __if_exists(Nontemplate::value) {
  14     typedef Nontemplate::value type2;
  15   }
  16
  17   __if_not_exists(Nontemplate::value) {
  18     typedef int type3;
  19   }
  20
  21   __if_exists(T::X) { // expected-warning{{dependent __if_exists declarations are ignored}}
  22     typedef T::X type4;
  23   }
  24 };
  25
  26 X<int>::type i1;
  27 X<int>::type2 i2; // expected-error{{no type named 'type2' in 'X<int>'}}
  28 X<int>::type3 i3;
  29 X<int>::type4 i4; // expected-error{{no type named 'type4' in 'X<int>'}}
  30
  31 struct HasFoo {
  32   void foo();
  33 };
  34 struct HasBar {
  35   void bar(int);
  36   void bar(float);
  37 };
  38
  39 template<typename T>
  40 void f(T t) {
  41   __if_exists(T::foo) {
  42     { }
  43     t.foo();
  44   }
  45
  46   __if_not_exists(T::bar) {
  47     int *i = t; // expected-error{{no viable conversion from 'HasFoo' to 'int *'}}
  48     { }
  49   }
  50
  51   int array2[] = {
  52     0,
  53     __if_exists(T::bar) {2, }// expected-warning{{dependent __if_exists declarations are ignored}}
  54     3
  55   };
  56 }
  57
  58 template void f(HasFoo); // expected-note{{in instantiation of function template specialization 'f<HasFoo>' requested here}}
  59 template void f(HasBar);
  60
  61 template<typename T, typename ...Ts>
  62 void g(T, Ts...) {
  63   __if_exists(T::operator Ts) { // expected-error{{__if_exists name contains unexpanded parameter pack 'Ts'}}
  64   }
  65
  66   __if_not_exists(Ts::operator T) { // expected-error{{__if_not_exists name contains unexpanded parameter pack 'Ts'}}
  67   }
  68 }