clang/test/SemaCXX/PR10177.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
   2 // RUN: %clang_cc1 -fsyntax-only -std=c++1y -verify %s -DCXX1Y
   3
   4 #ifndef CXX1Y
   5
   6 template<typename T, typename U, U> using alias_ref = T;
   7 template<typename T, typename U, U> void func_ref() {}
   8 template<typename T, typename U, U> struct class_ref {};
   9
  10 template<int N>
  11 struct U {
  12   static int a;
  13 };
  14
  15 template<int N> struct S; // expected-note 6{{here}}
  16
  17 template<int N>
  18 int U<N>::a = S<N>::kError; // expected-error 6{{undefined}}
  19
  20 template<typename T>
  21 void f() {
  22   (void)alias_ref<int, int&, U<0>::a>(); // expected-note {{here}}
  23   (void)func_ref<int, int&, U<1>::a>(); // expected-note {{here}}
  24   (void)class_ref<int, int&, U<2>::a>(); // expected-note {{here}}
  25 };
  26
  27 template<typename T>
  28 void not_instantiated() {
  29   // These cases (arguably) do not require instantiation of U<i>::a.
  30   (void)alias_ref<int, int&, U<3>::a>();
  31   (void)func_ref<int, int&, U<4>::a>();
  32   (void)class_ref<int, int&, U<5>::a>();
  33 };
  34
  35 template<int N>
  36 void fi() {
  37   (void)alias_ref<int, int&, U<N>::a>(); // expected-note {{here}}
  38   (void)func_ref<int, int&, U<N+1>::a>(); // expected-note {{here}}
  39   (void)class_ref<int, int&, U<N+2>::a>(); // expected-note {{here}}
  40 };
  41
  42 int main() {
  43   f<int>();   // expected-note 3{{here}}
  44   fi<10>();   // expected-note 3{{here}}
  45 }
  46
  47 namespace N {
  48   template<typename T> struct S { static int n; };
  49   template<typename T> int S<T>::n = 5;
  50   void g(int*);
  51   template<typename T> int f() {
  52     int k[S<T>::n];
  53     g(k);
  54     return k[3];
  55   }
  56   int j = f<int>();
  57 }
  58
  59 #else
  60
  61 namespace { template<typename> extern int n; }
  62 template<typename T> int g() { return n<int>; }
  63 namespace { extern template int n<int>; } // expected-error {{explicit instantiation declaration of 'n<int>' with internal linkage}}
  64
  65 #endif
  66