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#include <type_traits>
 
template<class T>
struct trait{ using type = typename T::type; };
 
template<class T, class U = typename trait<T>::type>
void f(int);
void f(...);
 
template<class T, class U = typename T::type>
void g(int);
void g(...);
 
template<class>
struct dependent_false : std::false_type{};
 
template<class T>
struct X{
    static_assert(dependent_false<T>(), "...");
    using type = void;
};
 
int main(){
    f<int>(0);
    g<X<int>>(0);
}

prog.cpp: In instantiation of ‘struct trait<int>’:
prog.cpp:6:19:   required from here
prog.cpp:4:44: error: ‘int’ is not a class, struct, or union type
prog.cpp: In function ‘int main()’:
prog.cpp:24:13: error: no matching function for call to ‘f(int)’
prog.cpp:24:13: note: candidate is:
prog.cpp:7:6: note: template<class T, class U> void f(int)
prog.cpp:7:6: note:   substitution of deduced template arguments resulted in errors seen above
prog.cpp: In instantiation of ‘struct X<int>’:
prog.cpp:10:19:   required from here
prog.cpp:19:5: error: static assertion failed: ...

Standard output is empty