creusot_contracts/std/iter/
take.rs

1#[cfg(creusot)]
2use crate::resolve::structural_resolve;
3use crate::{invariant::*, std::iter::Take, *};
4
5pub trait TakeExt<I> {
6    #[logic]
7    fn iter(self) -> I;
8
9    #[logic]
10    fn iter_mut(&mut self) -> &mut I;
11
12    #[logic]
13    fn n(self) -> Int;
14}
15
16impl<I> TakeExt<I> for Take<I> {
17    #[trusted]
18    #[logic(opaque)]
19    #[ensures(inv(self) ==> inv(result))]
20    fn iter(self) -> I {
21        dead
22    }
23
24    #[trusted]
25    #[logic(opaque)]
26    #[ensures((*self).iter() == *result && (^self).iter() == ^result)]
27    fn iter_mut(&mut self) -> &mut I {
28        dead
29    }
30
31    #[trusted]
32    #[logic(opaque)]
33    #[ensures(result >= 0 && result <= usize::MAX@)]
34    fn n(self) -> Int {
35        dead
36    }
37}
38
39impl<I> Resolve for Take<I> {
40    #[logic(open, prophetic, inline)]
41    fn resolve(self) -> bool {
42        resolve(self.iter())
43    }
44
45    #[trusted]
46    #[logic(prophetic)]
47    #[requires(structural_resolve(self))]
48    #[ensures(self.resolve())]
49    fn resolve_coherence(self) {}
50}
51
52impl<I: Iterator> Iterator for Take<I> {
53    #[logic(open, prophetic)]
54    fn completed(&mut self) -> bool {
55        pearlite! {
56            self.n() == 0 && resolve(self) ||
57            (*self).n() > 0 && (*self).n() == (^self).n() + 1 && self.iter_mut().completed()
58        }
59    }
60
61    #[logic(open, prophetic)]
62    fn produces(self, visited: Seq<Self::Item>, o: Self) -> bool {
63        pearlite! {
64            self.n() == o.n() + visited.len() && self.iter().produces(visited, o.iter())
65        }
66    }
67
68    #[logic(law)]
69    #[ensures(self.produces(Seq::empty(), self))]
70    fn produces_refl(self) {}
71
72    #[logic(law)]
73    #[requires(a.produces(ab, b))]
74    #[requires(b.produces(bc, c))]
75    #[ensures(a.produces(ab.concat(bc), c))]
76    fn produces_trans(a: Self, ab: Seq<Self::Item>, b: Self, bc: Seq<Self::Item>, c: Self) {}
77}
creusot_contracts/std/iter/take.rs

creusot_contracts/std/iter/
take.rs
