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  1. #include <type_traits>
  2.  
  3. class A {};
  4. class B : A {};
  5. class C : A {};
  6. class X{};
  7.  
  8. template<typename T>
  9. class D
  10. {
  11.     static_assert(std::is_base_of<A,T>::value, "T must be derived from A");
  12. };
  13.  
  14. int main()
  15. {
  16.     D<C> d_valid;
  17.     D<X> d_fails; // compilation fails
  18.  
  19.     return 0;
  20. }
Compilation error #stdin compilation error #stdout 0s 0KB
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stdin
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Standard input is empty
compilation info 
prog.cpp: In instantiation of 'class D<X>':
prog.cpp:17:10:   required from here
prog.cpp:11:5: error: static assertion failed: T must be derived from A
     static_assert(std::is_base_of<A,T>::value, "T must be derived from A");
     ^
stdout
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Standard output is empty
https://ideone.com/NqjNJV
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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