clang/test/SemaTemplate/instantiate-pure-virtual-function.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify -Wundefined-func-template %s
   2
   3 namespace GH74016 {
   4   template <typename T> class B {
   5   public:
   6     constexpr void foo(const T &) { bar(1); }
   7     virtual constexpr void bar(unsigned int) = 0;
   8   };
   9
  10   template <typename T> class D : public B<T> {
  11   public:
  12     constexpr void bar(unsigned int) override {}
  13   };
  14
  15   void test() {
  16     auto t = D<int>();
  17     t.foo(0);
  18   }
  19 };
  20
  21 namespace call_pure_virtual_function_from_virtual {
  22   template <typename T> class B {
  23   public:
  24     const void foo(const T &) { B::bar(1); } // expected-warning {{instantiation of function 'call_pure_virtual_function_from_virtual::B<int>::bar' required here, but no definition is available}}
  25     // expected-note@-1 {{add an explicit instantiation declaration to suppress this warning if 'call_pure_virtual_function_from_virtual::B<int>::bar' is explicitly instantiated in another translation unit}}
  26     virtual const void bar(unsigned int) = 0; // expected-note {{forward declaration of template entity is here}}
  27   };
  28
  29   template <typename T> class D : public B<T> {
  30   public:
  31     const void bar(unsigned int) override {}
  32   };
  33
  34   void test() {
  35     auto t = D<int>();
  36     t.foo(0); // expected-note {{in instantiation of member function 'call_pure_virtual_function_from_virtual::B<int>::foo' requested here}}
  37   }
  38 };
  39
  40 namespace non_pure_virtual_function {
  41   template <typename T> class B {
  42   public:
  43     constexpr void foo(const T &) { bar(1); }
  44
  45     virtual constexpr void bar(unsigned int); // expected-warning {{inline function 'non_pure_virtual_function::B<int>::bar' is not defined}}
  46     // expected-note@-1 {{forward declaration of template entity is here}}
  47     // expected-note@-2 {{forward declaration of template entity is here}}
  48     // expected-note@-3 {{forward declaration of template entity is here}}
  49   };
  50
  51   template <typename T> class D : public B<T> { // expected-warning {{instantiation of function 'non_pure_virtual_function::B<int>::bar' required here, but no definition is available}}
  52 // expected-warning@-1 {{instantiation of function 'non_pure_virtual_function::B<int>::bar' required here, but no definition is available}}
  53 // expected-warning@-2 {{instantiation of function 'non_pure_virtual_function::B<int>::bar' required here, but no definition is available}}
  54 // expected-note@-3 {{add an explicit instantiation declaration to suppress this warning if 'non_pure_virtual_function::B<int>::bar' is explicitly instantiated in another translation unit}}
  55 // expected-note@-4 {{add an explicit instantiation declaration to suppress this warning if 'non_pure_virtual_function::B<int>::bar' is explicitly instantiated in another translation unit}}
  56 // expected-note@-5 {{add an explicit instantiation declaration to suppress this warning if 'non_pure_virtual_function::B<int>::bar' is explicitly instantiated in another translation unit}}
  57 // expected-note@-6 {{used here}}
  58
  59   public:
  60     constexpr void bar(unsigned int) override { }
  61   };
  62
  63   void test() {
  64     auto t = D<int>();
  65     t.foo(0);
  66   }
  67 };