Struct rustc_borrowck::universal_regions::UniversalRegionIndices

struct UniversalRegionIndices<'tcx> {
    indices: FxIndexMap<Region<'tcx>, RegionVid>,
    pub fr_static: RegionVid,
    pub tainted_by_errors: Cell<Option<ErrorGuaranteed>>,
}

Fields

indices: FxIndexMap<Region<'tcx>, RegionVid>

For those regions that may appear in the parameter environment (’static and early-bound regions), we maintain a map from the ty::Region to the internal RegionVid we are using. This is used because trait matching and type-checking will feed us region constraints that reference those regions and we need to be able to map them to our internal RegionVid. This is basically equivalent to an GenericArgs, except that it also contains an entry for ReStatic – it might be nice to just use an args, and then handle ReStatic another way.

fr_static: RegionVid

The vid assigned to 'static. Used only for diagnostics.

tainted_by_errors: Cell<Option<ErrorGuaranteed>>

Whether we’ve encountered an error region. If we have, cancel all outlives errors, as they are likely bogus.

Implementations

impl<'tcx> UniversalRegionIndices<'tcx>

fn insert_late_bound_region(&mut self, r: Region<'tcx>, vid: RegionVid)

Initially, the UniversalRegionIndices map contains only the early-bound regions in scope. Once that is all setup, we come in later and instantiate the late-bound regions, and then we insert the ReLateParam version of those into the map as well. These are used for error reporting.

pub fn to_region_vid(&self, r: Region<'tcx>) -> RegionVid

Converts r into a local inference variable: r can either be a ReVar (i.e., already a reference to an inference variable) or it can be 'static or some early-bound region. This is useful when taking the results from type-checking and trait-matching, which may sometimes reference those regions from the ParamEnv. It is also used during initialization. Relies on the indices map having been fully initialized.

pub fn fold_to_region_vids<T>(&self, tcx: TyCtxt<'tcx>, value: T) -> T

where T: TypeFoldable<TyCtxt<'tcx>>,

Replaces all free regions in value with region vids, as returned by to_region_vid.

Trait Implementations

impl<'tcx> Debug for UniversalRegionIndices<'tcx>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

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: 64 bytes