extern_spec_std_time_Duration_checked_sub

creusot_contracts::std::time

Function extern_spec_std_time_Duration_checked_sub 

Source 
pub fn extern_spec_std_time_Duration_checked_sub(
    self_: Duration,
    rhs: Duration,
) -> Option<Duration>
Expand description

extern spec for ::std::time::Duration::checked_sub

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

terminates

ghost

ensures 

self@ - rhs@ < 0 ==> result == None

ensures 

self@ - rhs@ >= 0 ==> result.deep_model() == Some(self@ - rhs@)