Struct rustc_borrowck::member_constraints::MemberConstraintSet

pub(crate) struct MemberConstraintSet<'tcx, R>where
    R: Copy + Eq,{
    first_constraints: FxHashMap<R, NllMemberConstraintIndex>,
    constraints: IndexVec<NllMemberConstraintIndex, NllMemberConstraint<'tcx>>,
    choice_regions: Vec<RegionVid>,
}

Compactly stores a set of R0 member of [R1...Rn] constraints, indexed by the region R0.

Fields

first_constraints: FxHashMap<R, NllMemberConstraintIndex>

Stores the first “member” constraint for a given R0. This is an index into the constraints vector below.

constraints: IndexVec<NllMemberConstraintIndex, NllMemberConstraint<'tcx>>

Stores the data about each R0 member of [R1..Rn] constraint. These are organized into a linked list, so each constraint contains the index of the next constraint with the same R0.

choice_regions: Vec<RegionVid>

Stores the R1..Rn regions for all sets. For any given constraint, we keep two indices so that we can pull out a slice.

Implementations

impl<'tcx> MemberConstraintSet<'tcx, RegionVid>

pub(crate) fn push_constraint(
    &mut self,
    m_c: &MemberConstraint<'tcx>,
    to_region_vid: impl FnMut(Region<'tcx>) -> RegionVid
)

Pushes a member constraint into the set.

The input member constraint m_c is in the form produced by the rustc_middle::infer code.

The to_region_vid callback fn is used to convert the regions within into RegionVid format – it typically consults the UniversalRegions data structure that is known to the caller (but which this code is unaware of).

impl<'tcx, R1> MemberConstraintSet<'tcx, R1>where
    R1: Copy + Hash + Eq,

pub(crate) fn into_mapped<R2>(
    self,
    map_fn: impl FnMut(R1) -> R2
) -> MemberConstraintSet<'tcx, R2>where
    R2: Copy + Hash + Eq,

Remap the “member region” key using map_fn, producing a new member constraint set. This is used in the NLL code to map from the original RegionVid to an scc index. In some cases, we may have multiple R1 values mapping to the same R2 key – that is ok, the two sets will be merged.

impl<'tcx, R> MemberConstraintSet<'tcx, R>where
    R: Copy + Hash + Eq,

pub(crate) fn all_indices(
    &self
) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_

pub(crate) fn indices(
    &self,
    member_region_vid: R
) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_

Iterate down the constraint indices associated with a given peek-region. You can then use choice_regions and other methods to access data.

pub(crate) fn choice_regions(
    &self,
    pci: NllMemberConstraintIndex
) -> &[RegionVid]

Returns the “choice regions” for a given member constraint. This is the R1..Rn from a constraint like:

R0 member of [R1..Rn]

Trait Implementations

impl Default for MemberConstraintSet<'_, RegionVid>

fn default() -> Self

Returns the “default value” for a type.

impl<'tcx, R> Index<NllMemberConstraintIndex> for MemberConstraintSet<'tcx, R>where
    R: Copy + Eq,

type Output = NllMemberConstraint<'tcx>

The returned type after indexing.

fn index(&self, i: NllMemberConstraintIndex) -> &NllMemberConstraint<'tcx>

Performs the indexing (container[index]) operation.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 80 bytes