Struct rustc_mir::borrow_check::constraints::graph::ConstraintGraph

pub(crate) struct ConstraintGraph<D: ConstraintGraphDirecton> {
    _direction: D,
    first_constraints: IndexVec<RegionVid, Option<OutlivesConstraintIndex>>,
    next_constraints: IndexVec<OutlivesConstraintIndex, Option<OutlivesConstraintIndex>>,
}

The construct graph organizes the constraints by their end-points. It can be used to view a R1: R2 constraint as either an edge R1 -> R2 or R2 -> R1 depending on the direction type D.

Fields

_direction: D

first_constraints: IndexVec<RegionVid, Option<OutlivesConstraintIndex>>

next_constraints: IndexVec<OutlivesConstraintIndex, Option<OutlivesConstraintIndex>>

Implementations

impl<D: ConstraintGraphDirecton> ConstraintGraph<D>

pub(crate) fn new(
    direction: D,
    set: &OutlivesConstraintSet,
    num_region_vars: usize
) -> Self

Creates a “dependency graph” where each region constraint R1: R2 is treated as an edge R1 -> R2. We use this graph to construct SCCs for region inference but also for error reporting.

pub(crate) fn region_graph<'rg>(
    &'rg self,
    set: &'rg OutlivesConstraintSet,
    static_region: RegionVid
) -> RegionGraph<'rg, D>

Given the constraint set from which this graph was built creates a region graph so that you can iterate over regions and not constraints.

pub(crate) fn outgoing_edges<'a>(
    &'a self,
    region_sup: RegionVid,
    constraints: &'a OutlivesConstraintSet,
    static_region: RegionVid
) -> Edges<'a, D>

Given a region R, iterate over all constraints R: R1.