bjoernager/rust
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Don't elaborate non-obligations into obligations

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This commit is contained in:
Michael Goulet 2023-03-26 20:33:54 +00:00
parent 96bd50dd47
commit 1ce4b37900
20 changed files with 112 additions and 131 deletions
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34
compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs
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@ -318,16 +318,8 @@ fn check_predicates<'tcx>(
span: Span,
) {
let instantiated = tcx.predicates_of(impl1_def_id).instantiate(tcx, impl1_substs);
let impl1_predicates: Vec<_> = traits::elaborate_predicates_with_span(
tcx,
std::iter::zip(
instantiated.predicates,
// Don't drop predicates (unsound!) because `spans` is too short
instantiated.spans.into_iter().chain(std::iter::repeat(span)),
),
)
.map(|obligation| (obligation.predicate, obligation.cause.span))
.collect();
let impl1_predicates: Vec<_> =
traits::elaborate_predicates_with_span(tcx, instantiated.into_iter()).collect();
let mut impl2_predicates = if impl2_node.is_from_trait() {
// Always applicable traits have to be always applicable without any
@ -341,7 +333,6 @@ fn check_predicates<'tcx>(
.predicates
.into_iter(),
)
.map(|obligation| obligation.predicate)
.collect()
};
debug!(?impl1_predicates, ?impl2_predicates);
@ -361,12 +352,16 @@ fn check_predicates<'tcx>(
// which is sound because we forbid impls like the following
//
// impl<D: Debug> AlwaysApplicable for D { }
let always_applicable_traits = impl1_predicates.iter().copied().filter(|&(predicate, _)| {
matches!(
trait_predicate_kind(tcx, predicate),
Some(TraitSpecializationKind::AlwaysApplicable)
)
});
let always_applicable_traits = impl1_predicates
.iter()
.copied()
.filter(|&(predicate, _)| {
matches!(
trait_predicate_kind(tcx, predicate),
Some(TraitSpecializationKind::AlwaysApplicable)
)
})
.map(|(pred, _span)| pred);
// Include the well-formed predicates of the type parameters of the impl.
for arg in tcx.impl_trait_ref(impl1_def_id).unwrap().subst_identity().substs {
@ -380,10 +375,7 @@ fn check_predicates<'tcx>(
traits::elaborate_obligations(tcx, obligations).map(|obligation| obligation.predicate),
)
}
impl2_predicates.extend(
traits::elaborate_predicates_with_span(tcx, always_applicable_traits)
.map(|obligation| obligation.predicate),
);
impl2_predicates.extend(traits::elaborate_predicates(tcx, always_applicable_traits));
for (predicate, span) in impl1_predicates {
if !impl2_predicates.iter().any(|pred2| trait_predicates_eq(tcx, predicate, *pred2, span)) {