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9 - Make more use of let_chains

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Continuation of #94376.

cc #53667
This commit is contained in:
Caio
2022-03-01 18:34:35 -03:00
parent f0c4da4998
commit a7b4d667fe
8 changed files with 176 additions and 218 deletions
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72
compiler/rustc_trait_selection/src/traits/relationships.rs
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@@ -12,50 +12,38 @@ pub(crate) fn update<'tcx, T>(
T: TraitEngine<'tcx>,
{
// (*) binder skipped
if let ty::PredicateKind::Trait(predicate) = obligation.predicate.kind().skip_binder() {
if let Some(ty) =
infcx.shallow_resolve(predicate.self_ty()).ty_vid().map(|t| infcx.root_var(t))
{
if infcx
.tcx
.lang_items()
.sized_trait()
.map_or(false, |st| st != predicate.trait_ref.def_id)
{
let new_self_ty = infcx.tcx.types.unit;
if let ty::PredicateKind::Trait(tpred) = obligation.predicate.kind().skip_binder()
&& let Some(ty) = infcx.shallow_resolve(tpred.self_ty()).ty_vid().map(|t| infcx.root_var(t))
&& infcx.tcx.lang_items().sized_trait().map_or(false, |st| st != tpred.trait_ref.def_id)
{
let new_self_ty = infcx.tcx.types.unit;
let trait_ref = ty::TraitRef {
substs: infcx
.tcx
.mk_substs_trait(new_self_ty, &predicate.trait_ref.substs[1..]),
..predicate.trait_ref
};
let trait_ref = ty::TraitRef {
substs: infcx.tcx.mk_substs_trait(new_self_ty, &tpred.trait_ref.substs[1..]),
..tpred.trait_ref
};
// Then contstruct a new obligation with Self = () added
// to the ParamEnv, and see if it holds.
let o = rustc_infer::traits::Obligation::new(
ObligationCause::dummy(),
obligation.param_env,
obligation
.predicate
.kind()
.map_bound(|_| {
// (*) binder moved here
ty::PredicateKind::Trait(ty::TraitPredicate {
trait_ref,
constness: predicate.constness,
polarity: predicate.polarity,
})
})
.to_predicate(infcx.tcx),
);
// Don't report overflow errors. Otherwise equivalent to may_hold.
if let Ok(result) = infcx.probe(|_| infcx.evaluate_obligation(&o)) {
if result.may_apply() {
engine.relationships().entry(ty).or_default().self_in_trait = true;
}
}
}
// Then contstruct a new obligation with Self = () added
// to the ParamEnv, and see if it holds.
let o = rustc_infer::traits::Obligation::new(
ObligationCause::dummy(),
obligation.param_env,
obligation
.predicate
.kind()
.map_bound(|_| {
// (*) binder moved here
ty::PredicateKind::Trait(ty::TraitPredicate {
trait_ref,
constness: tpred.constness,
polarity: tpred.polarity,
})
})
.to_predicate(infcx.tcx),
);
// Don't report overflow errors. Otherwise equivalent to may_hold.
if let Ok(result) = infcx.probe(|_| infcx.evaluate_obligation(&o)) && result.may_apply() {
engine.relationships().entry(ty).or_default().self_in_trait = true;
}
}