Struct rustc_infer::infer::region_constraints::RegionConstraintStorage

pub struct RegionConstraintStorage<'tcx> {
    var_infos: IndexVec<RegionVid, RegionVariableInfo>,
    data: RegionConstraintData<'tcx>,
    lubs: FxHashMap<TwoRegions<'tcx>, RegionVid>,
    glbs: FxHashMap<TwoRegions<'tcx>, RegionVid>,
    pub(super) unification_table: UnificationTableStorage<RegionVid>,
    any_unifications: bool,
}

Fields

var_infos: IndexVec<RegionVid, RegionVariableInfo>

For each RegionVid, the corresponding RegionVariableOrigin.

data: RegionConstraintData<'tcx>

lubs: FxHashMap<TwoRegions<'tcx>, RegionVid>

For a given pair of regions (R1, R2), maps to a region R3 that is designated as their LUB (edges R1 <= R3 and R2 <= R3 exist). This prevents us from making many such regions.

glbs: FxHashMap<TwoRegions<'tcx>, RegionVid>

For a given pair of regions (R1, R2), maps to a region R3 that is designated as their GLB (edges R3 <= R1 and R3 <= R2 exist). This prevents us from making many such regions.

unification_table: UnificationTableStorage<RegionVid>

When we add a R1 == R2 constriant, we currently add (a) edges R1 <= R2 and R2 <= R1 and (b) we unify the two regions in this table. You can then call opportunistic_resolve_var early which will map R1 and R2 to some common region (i.e., either R1 or R2). This is important when fulfillment, dropck and other such code is iterating to a fixed point, because otherwise we sometimes would wind up with a fresh stream of region variables that have been equated but appear distinct.

any_unifications: bool

a flag set to true when we perform any unifications; this is used to micro-optimize take_and_reset_data

Implementations

impl<'tcx> RegionConstraintStorage<'tcx>

pub fn new() -> Self

pub(crate) fn with_log<'a>(
    &'a mut self,
    undo_log: &'a mut InferCtxtUndoLogs<'tcx>
) -> RegionConstraintCollector<'a, 'tcx>

fn rollback_undo_entry(&mut self, undo_entry: UndoLog<'tcx>)

Trait Implementations

impl<'tcx> Default for RegionConstraintStorage<'tcx>

fn default() -> RegionConstraintStorage<'tcx>

Returns the “default value” for a type.

impl<'tcx> Rollback<UndoLog<'tcx>> for RegionConstraintStorage<'tcx>

fn reverse(&mut self, undo: UndoLog<'tcx>)