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Revert "Auto merge of #79209 - spastorino:trait-inheritance-self, r=nikomatsakis"

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This reverts commit 349b3b324d, reversing
changes made to b776d1c3e3.
This commit is contained in:
Santiago Pastorino 2020-12-02 12:19:38 -03:00
parent b7ebc6b0c1
commit 37354ebc97
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GPG key ID: 8131A24E0C79EFAF
28 changed files with 152 additions and 499 deletions
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34
compiler/rustc_infer/src/traits/util.rs
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@ -1,10 +1,9 @@
use smallvec::smallvec;
use crate::traits::{Obligation, ObligationCause, PredicateObligation};
use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
use rustc_data_structures::fx::FxHashSet;
use rustc_middle::ty::outlives::Component;
use rustc_middle::ty::{self, ToPredicate, TyCtxt, WithConstness};
use rustc_span::symbol::Ident;
pub fn anonymize_predicate<'tcx>(
tcx: TyCtxt<'tcx>,
@ -288,37 +287,6 @@ pub fn transitive_bounds<'tcx>(
elaborate_trait_refs(tcx, bounds).filter_to_traits()
}
/// A specialized variant of `elaborate_trait_refs` that only elaborates trait references that may
/// define the given associated type `assoc_name`. It uses the
/// `super_predicates_that_define_assoc_type` query to avoid enumerating super-predicates that
/// aren't related to `assoc_item`. This is used when resolving types like `Self::Item` or
/// `T::Item` and helps to avoid cycle errors (see e.g. #35237).
pub fn transitive_bounds_that_define_assoc_type<'tcx>(
tcx: TyCtxt<'tcx>,
bounds: impl Iterator<Item = ty::PolyTraitRef<'tcx>>,
assoc_name: Ident,
) -> FxIndexSet<ty::PolyTraitRef<'tcx>> {
let mut stack: Vec<_> = bounds.collect();
let mut trait_refs = FxIndexSet::default();
while let Some(trait_ref) = stack.pop() {
if trait_refs.insert(trait_ref) {
let super_predicates =
tcx.super_predicates_that_define_assoc_type((trait_ref.def_id(), Some(assoc_name)));
for (super_predicate, _) in super_predicates.predicates {
let bound_predicate = super_predicate.bound_atom();
let subst_predicate = super_predicate
.subst_supertrait(tcx, &bound_predicate.rebind(trait_ref.skip_binder()));
if let Some(binder) = subst_predicate.to_opt_poly_trait_ref() {
stack.push(binder.value);
}
}
}
}
trait_refs
}
///////////////////////////////////////////////////////////////////////////
// Other
///////////////////////////////////////////////////////////////////////////