Struct VarArgs4
variadic
pub struct VarArgs4<A, B, C, D>(_, _, _, _);
impl<T, A, B, C> Variadic<T, A, B, C> for VarArgs4<T, A, B, C>
type OneLess = VarArgs3<A, B, C>
fn pop(self) -> (Option<T>, Self::OneLess)