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refactor builtin unsize handling, extend comments

This commit is contained in:
lcnr 2023-07-28 12:50:23 +02:00
parent f239bb6bea
commit f1753ff8f8
8 changed files with 270 additions and 217 deletions

View file

@ -57,6 +57,7 @@ pub enum Certainty {
impl Certainty {
pub const AMBIGUOUS: Certainty = Certainty::Maybe(MaybeCause::Ambiguity);
pub const OVERFLOW: Certainty = Certainty::Maybe(MaybeCause::Overflow);
/// Use this function to merge the certainty of multiple nested subgoals.
///
@ -66,7 +67,7 @@ impl Certainty {
/// success, we merge these two responses. This results in ambiguity.
///
/// If we unify ambiguity with overflow, we return overflow. This doesn't matter
/// inside of the solver as we distinguish ambiguity from overflow. It does
/// inside of the solver as we do not distinguish ambiguity from overflow. It does
/// however matter for diagnostics. If `T: Foo` resulted in overflow and `T: Bar`
/// in ambiguity without changing the inference state, we still want to tell the
/// user that `T: Baz` results in overflow.

View file

@ -1381,12 +1381,24 @@ impl<'tcx> ToPredicate<'tcx, Clause<'tcx>> for PolyTraitPredicate<'tcx> {
}
}
impl<'tcx> ToPredicate<'tcx> for OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>> {
fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
ty::Binder::dummy(PredicateKind::Clause(ClauseKind::RegionOutlives(self))).to_predicate(tcx)
}
}
impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
self.map_bound(|p| PredicateKind::Clause(ClauseKind::RegionOutlives(p))).to_predicate(tcx)
}
}
impl<'tcx> ToPredicate<'tcx> for OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
ty::Binder::dummy(PredicateKind::Clause(ClauseKind::TypeOutlives(self))).to_predicate(tcx)
}
}
impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
self.map_bound(|p| PredicateKind::Clause(ClauseKind::TypeOutlives(p))).to_predicate(tcx)