[Bug c++/104691] SFINAE does not disable static_assert

redi at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Fri Feb 25 17:38:41 GMT 2022


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104691

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:

template<typename T>
typename T::foo
f(T) { }

template<typename T>
typename T::bar
f(T) { static_assert(false, ""); }

struct X { using foo = void; };

int main()
{
  X x;
  f(x);
}


All compilers reject this code.

Something as simple as static_assert(sizeof(T) != 0, ""); can be used to make
it dependent, and then it will only fail when the template is instantiated.


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