@Lundin shows how to check if a passed expression is an array at compile-time here: Lvalue conversion of _Generic controlling expression involving array clang warning wrong?:

#define IS_ARRAY(T)            
  _Generic( &(T),              
    typeof(*T) (*)[]  : true,  
    default           : false  
  )

Can we further differentiate between an array which has variable length array type and one which does not?

Why do I need this? I have a generic SWAP() that does not work for VLAs. I would like to check at compile-time (static_assert) whether a VLA was passed to SWAP() and guide the user to use another variant of SWAP() that work for VLAs.