rustc_borrowck/polonius/
constraints.rs

1use rustc_middle::ty::RegionVid;
2use rustc_mir_dataflow::points::PointIndex;
3
4/// A localized outlives constraint reifies the CFG location where the outlives constraint holds,
5/// within the origins themselves as if they were different from point to point: from `a: b`
6/// outlives constraints to `a@p: b@p`, where `p` is the point in the CFG.
7///
8/// This models two sources of constraints:
9/// - constraints that traverse the subsets between regions at a given point, `a@p: b@p`. These
10///   depend on typeck constraints generated via assignments, calls, etc.
11/// - constraints that traverse the CFG via the same region, `a@p: a@q`, where `p` is a predecessor
12///   of `q`. These depend on the liveness of the regions at these points, as well as their
13///   variance.
14///
15/// The `source` origin at `from` flows into the `target` origin at `to`.
16///
17/// This dual of NLL's [crate::constraints::OutlivesConstraint] therefore encodes the
18/// position-dependent outlives constraints used by Polonius, to model the flow-sensitive loan
19/// propagation via reachability within a graph of localized constraints.
20#[derive(#[automatically_derived]
impl ::core::marker::Copy for LocalizedOutlivesConstraint { }Copy, #[automatically_derived]
impl ::core::clone::Clone for LocalizedOutlivesConstraint {
    #[inline]
    fn clone(&self) -> LocalizedOutlivesConstraint {
        let _: ::core::clone::AssertParamIsClone<RegionVid>;
        let _: ::core::clone::AssertParamIsClone<PointIndex>;
        *self
    }
}Clone, #[automatically_derived]
impl ::core::cmp::PartialEq for LocalizedOutlivesConstraint {
    #[inline]
    fn eq(&self, other: &LocalizedOutlivesConstraint) -> bool {
        self.source == other.source && self.from == other.from &&
                self.target == other.target && self.to == other.to
    }
}PartialEq, #[automatically_derived]
impl ::core::cmp::Eq for LocalizedOutlivesConstraint {
    #[inline]
    #[doc(hidden)]
    #[coverage(off)]
    fn assert_receiver_is_total_eq(&self) {
        let _: ::core::cmp::AssertParamIsEq<RegionVid>;
        let _: ::core::cmp::AssertParamIsEq<PointIndex>;
    }
}Eq, #[automatically_derived]
impl ::core::fmt::Debug for LocalizedOutlivesConstraint {
    #[inline]
    fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
        ::core::fmt::Formatter::debug_struct_field4_finish(f,
            "LocalizedOutlivesConstraint", "source", &self.source, "from",
            &self.from, "target", &self.target, "to", &&self.to)
    }
}Debug, #[automatically_derived]
impl ::core::hash::Hash for LocalizedOutlivesConstraint {
    #[inline]
    fn hash<__H: ::core::hash::Hasher>(&self, state: &mut __H) {
        ::core::hash::Hash::hash(&self.source, state);
        ::core::hash::Hash::hash(&self.from, state);
        ::core::hash::Hash::hash(&self.target, state);
        ::core::hash::Hash::hash(&self.to, state)
    }
}Hash)]
21pub(crate) struct LocalizedOutlivesConstraint {
22    pub source: RegionVid,
23    pub from: PointIndex,
24    pub target: RegionVid,
25    pub to: PointIndex,
26}
27
28/// A container of [LocalizedOutlivesConstraint]s that can be turned into a traversable
29/// `rustc_data_structures` graph.
30#[derive(#[automatically_derived]
impl ::core::clone::Clone for LocalizedOutlivesConstraintSet {
    #[inline]
    fn clone(&self) -> LocalizedOutlivesConstraintSet {
        LocalizedOutlivesConstraintSet {
            outlives: ::core::clone::Clone::clone(&self.outlives),
        }
    }
}Clone, #[automatically_derived]
impl ::core::default::Default for LocalizedOutlivesConstraintSet {
    #[inline]
    fn default() -> LocalizedOutlivesConstraintSet {
        LocalizedOutlivesConstraintSet {
            outlives: ::core::default::Default::default(),
        }
    }
}Default, #[automatically_derived]
impl ::core::fmt::Debug for LocalizedOutlivesConstraintSet {
    #[inline]
    fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
        ::core::fmt::Formatter::debug_struct_field1_finish(f,
            "LocalizedOutlivesConstraintSet", "outlives", &&self.outlives)
    }
}Debug)]
31pub(crate) struct LocalizedOutlivesConstraintSet {
32    pub outlives: Vec<LocalizedOutlivesConstraint>,
33}
34
35impl LocalizedOutlivesConstraintSet {
36    pub(crate) fn push(&mut self, constraint: LocalizedOutlivesConstraint) {
37        if constraint.source == constraint.target && constraint.from == constraint.to {
38            // 'a@p: 'a@p is pretty uninteresting
39            return;
40        }
41        self.outlives.push(constraint);
42    }
43}
rustc_borrowck/polonius/constraints.rs

rustc_borrowck/polonius/
constraints.rs
