Function extern_spec_T_A_VecDeque_T_A_len 

pub fn extern_spec_T_A_VecDeque_T_A_len<T, A: Allocator>(
    self_: &VecDeque<T, A>,
) -> usize

extern spec for VecDeque<T, A>::len

This is not a real function: its only use is for documentation.

terminates

ghost

ensures

result@ == self@.len()