clang/test/SemaTemplate/instantiate-abbreviated-template.cpp

   1 // RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
   2
   3 template<typename...>
   4 concept C = false; // expected-note 9{{because}}
   5
   6 template<typename T>
   7 struct S {
   8     template<typename U>
   9     static void foo1(U a, auto b);
  10     static void foo2(T a, C<T> auto b);
  11     // expected-note@-1{{candidate template ignored}} expected-note@-1{{because}}
  12     static void foo3(T a, C<decltype(a)> auto b);
  13     // expected-note@-1{{candidate template ignored}} expected-note@-1{{because}}
  14     static void foo4(T a, C<decltype(a)> auto b, const C<decltype(b)> auto &&c);
  15     // expected-note@-1{{candidate template ignored}} expected-note@-1{{because}}
  16 };
  17
  18 using sf1 = decltype(S<int>::foo1(1, 2));
  19 using sf2 = decltype(S<int>::foo2(1, 2)); // expected-error{{no matching function}}
  20 using sf3 = decltype(S<int>::foo3(1, 2)); // expected-error{{no matching function}}
  21 using sf4 = decltype(S<int>::foo4(1, 2, 3)); // expected-error{{no matching function}}
  22
  23
  24 template<typename... T>
  25 struct G {
  26     static void foo1(auto a, const C<decltype(a)> auto &&... b);
  27     // expected-note@-1{{candidate template ignored}} expected-note@-1{{because}} expected-note@-1 3{{and}}
  28     static void foo2(auto a, const C<decltype(a), T> auto &&... b);
  29     // expected-note@-1{{candidate template ignored}} expected-note@-1{{because}} expected-note@-1{{and}}
  30 };
  31
  32 using gf1 = decltype(G<int, char>::foo1('a', 1, 2, 3, 4)); // expected-error{{no matching function}}
  33 using gf2 = decltype(G<int, char>::foo2('a', 1, 2)); // expected-error{{no matching function}}
  34
  35
  36 // Regression (bug #45102): check that instantiation works where there is no
  37 // TemplateTypeParmDecl
  38 template <typename T> using id = T;
  39
  40 template <typename T>
  41 constexpr void g() {
  42   id<void (T)> f;
  43 }
  44
  45 static_assert((g<int>(), true));