package
static if(!(is(Node == Tree!(Ridx, L, R, OP, Leafs), string Ridx, L, R, string OP, Leafs...)))
static if(!(is(Node == Leaf!(Ridx, idx, Ts), string Ridx, string idx, Ts)))
static if(is(Node == Func!(Ridx, fun, Leafs), string Ridx, alias fun, Leafs...))