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Remove super_traits_of query, just leave a helper function

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Santiago Pastorino 2020-11-25 12:53:52 -03:00
parent a6136d8b83
commit 35bf466a27
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3 changed files with 23 additions and 31 deletions
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6
compiler/rustc_middle/src/query/mod.rs
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@ -436,12 +436,6 @@ rustc_queries! {
desc { |tcx| "computing the super predicates of `{}`", tcx.def_path_str(key) }
}
/// Maps from the `DefId` of a trait to the list of
/// all the ancestors super traits.
query super_traits_of(key: DefId) -> Lrc<FxHashSet<DefId>> {
desc { |tcx| "computing the super traits of `{}`", tcx.def_path_str(key) }
}
/// The `Option<Ident>` is the name of an associated type. If it is `None`, then this query
/// returns the full set of predicates. If `Some<Ident>`, then the query returns only the
/// subset of super-predicates that reference traits that define the given associated type.

23
compiler/rustc_middle/src/ty/context.rs
View file

@ -2095,6 +2095,29 @@ impl<'tcx> TyCtxt<'tcx> {
})
}
/// Computes the def-ids of the transitive super-traits of `trait_def_id`. This (intentionally)
/// does not compute the full elaborated super-predicates but just the set of def-ids. It is used
/// to identify which traits may define a given associated type to help avoid cycle errors.
/// Returns `Lrc<FxHashSet<DefId>>` so that cloning is cheaper.
fn super_traits_of(self, trait_def_id: DefId) -> Lrc<FxHashSet<DefId>> {
let mut set = FxHashSet::default();
let mut stack = vec![trait_def_id];
while let Some(trait_did) = stack.pop() {
if !set.insert(trait_did) {
continue;
}
let generic_predicates = self.super_predicates_of(trait_did);
for (predicate, _) in generic_predicates.predicates {
if let ty::PredicateAtom::Trait(data, _) = predicate.skip_binders() {
stack.push(data.def_id());
}
}
}
Lrc::new(set)
}
/// Given a closure signature, returns an equivalent fn signature. Detuples
/// and so forth -- so e.g., if we have a sig with `Fn<(u32, i32)>` then
/// you would get a `fn(u32, i32)`.