c++11 - static constexpr template array member recursively required by itself -

i want static constexpr array of class-elements inside templated class similar following code:

struct element {     unsigned i;     constexpr element (unsigned i) : i(i) { } };  template <bool reverse> struct template {      static constexpr element element[] = {          element (reverse ? 1 : 0),          element (reverse ? 0 : 1),      }; };  int main (int argc, char **argv) {     return template<true>::element[0].i; } 

of course, actual element structure more complex in example, shows problem. if compile wit gcc error recursive dependency:

test.cc: in instantiation of ‘constexpr element template<true>::element [2]’: test.cc:11:27:   recursively required ‘constexpr element template<true>::element [2]’ test.cc:11:27:   required ‘constexpr element template<true>::element [2]’ test.cc:20:2:   required here test.cc:11:27: fatal error: template instantiation depth exceeds maximum of 900 (use -ftemplate-depth= increase maximum)   static constexpr element element[] = {                        ^ compilation terminated. 

first of curious how circumvent error glade if hint cause of or why such construct should not valid...

you need specify size of element array. element element[] isn't valid c++.

template <bool reverse> struct template {      static constexpr element element[2] = {          element (reverse ? 1 : 0),          element (reverse ? 0 : 1),      }; };