Struct rustc_infer::infer::canonical::Canonical

pub struct Canonical<'tcx, V> {
    pub max_universe: UniverseIndex,
    pub variables: &'tcx List<CanonicalVarInfo<'tcx>>,
    pub value: V,
}

A “canonicalized” type V is one where all free inference variables have been rewritten to “canonical vars”. These are numbered starting from 0 in order of first appearance.

Fields

max_universe: UniverseIndex

variables: &'tcx List<CanonicalVarInfo<'tcx>>

value: V

Trait Implementations

impl<'tcx, V> CanonicalExt<'tcx, V> for Canonical<'tcx, V>

fn substitute(
    &self,
    tcx: TyCtxt<'tcx>,
    var_values: &CanonicalVarValues<'tcx>
) -> Vwhere
    V: TypeFoldable<'tcx>,

Instantiate the wrapped value, replacing each canonical value with the value given in var_values.

fn substitute_projected<T>(
    &self,
    tcx: TyCtxt<'tcx>,
    var_values: &CanonicalVarValues<'tcx>,
    projection_fn: impl FnOnce(&V) -> T
) -> Twhere
    T: TypeFoldable<'tcx>,

Allows one to apply a substitute to some subset of self.value. Invoke projection_fn with self.value to get a value V that is expressed in terms of the same canonical variables bound in self (usually this extracts from subset of self). Apply the substitution var_values to this value V, replacing each of the canonical variables.

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.