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Remove default trait RPITIT candidates

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This commit is contained in:
Michael Goulet 2023-01-17 22:12:23 +00:00
parent 3eb5c4581a
commit be55ad53a1
1 changed files with 3 additions and 33 deletions
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36
compiler/rustc_trait_selection/src/traits/project.rs
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@ -90,15 +90,7 @@ enum ProjectionCandidate<'tcx> {
/// From an "impl" (or a "pseudo-impl" returned by select) /// From an "impl" (or a "pseudo-impl" returned by select)
Select(Selection<'tcx>), Select(Selection<'tcx>),
ImplTraitInTrait(ImplTraitInTraitCandidate<'tcx>), ImplTraitInTrait(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>),
}
#[derive(PartialEq, Eq, Debug)]
enum ImplTraitInTraitCandidate<'tcx> {
// The `impl Trait` from a trait function's default body
Trait,
// A concrete type provided from a trait's `impl Trait` from an impl
Impl(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>),
} }
enum ProjectionCandidateSet<'tcx> { enum ProjectionCandidateSet<'tcx> {
@ -1292,17 +1284,6 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
let tcx = selcx.tcx(); let tcx = selcx.tcx();
if tcx.def_kind(obligation.predicate.def_id) == DefKind::ImplTraitPlaceholder { if tcx.def_kind(obligation.predicate.def_id) == DefKind::ImplTraitPlaceholder {
let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.def_id); let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.def_id);
// If we are trying to project an RPITIT with trait's default `Self` parameter,
// then we must be within a default trait body.
if obligation.predicate.self_ty()
== ty::InternalSubsts::identity_for_item(tcx, obligation.predicate.def_id).type_at(0)
&& tcx.associated_item(trait_fn_def_id).defaultness(tcx).has_value()
{
candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(
ImplTraitInTraitCandidate::Trait,
));
return;
}
let trait_def_id = tcx.parent(trait_fn_def_id); let trait_def_id = tcx.parent(trait_fn_def_id);
let trait_substs = let trait_substs =
@ -1313,9 +1294,7 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
let _ = selcx.infcx.commit_if_ok(|_| { let _ = selcx.infcx.commit_if_ok(|_| {
match selcx.select(&obligation.with(tcx, trait_predicate)) { match selcx.select(&obligation.with(tcx, trait_predicate)) {
Ok(Some(super::ImplSource::UserDefined(data))) => { Ok(Some(super::ImplSource::UserDefined(data))) => {
candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait( candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(data));
ImplTraitInTraitCandidate::Impl(data),
));
Ok(()) Ok(())
} }
Ok(None) => { Ok(None) => {
@ -1777,18 +1756,9 @@ fn confirm_candidate<'cx, 'tcx>(
ProjectionCandidate::Select(impl_source) => { ProjectionCandidate::Select(impl_source) => {
confirm_select_candidate(selcx, obligation, impl_source) confirm_select_candidate(selcx, obligation, impl_source)
} }
ProjectionCandidate::ImplTraitInTrait(ImplTraitInTraitCandidate::Impl(data)) => { ProjectionCandidate::ImplTraitInTrait(data) => {
confirm_impl_trait_in_trait_candidate(selcx, obligation, data) confirm_impl_trait_in_trait_candidate(selcx, obligation, data)
} }
// If we're projecting an RPITIT for a default trait body, that's just
// the same def-id, but as an opaque type (with regular RPIT semantics).
ProjectionCandidate::ImplTraitInTrait(ImplTraitInTraitCandidate::Trait) => Progress {
term: selcx
.tcx()
.mk_opaque(obligation.predicate.def_id, obligation.predicate.substs)
.into(),
obligations: vec![],
},
}; };
// When checking for cycle during evaluation, we compare predicates with // When checking for cycle during evaluation, we compare predicates with