diff options
Diffstat (limited to 'compiler/rustc_infer/src/traits/util.rs')
-rw-r--r-- | compiler/rustc_infer/src/traits/util.rs | 82 |
1 files changed, 33 insertions, 49 deletions
diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs index 3c566e0dd..50190058a 100644 --- a/compiler/rustc_infer/src/traits/util.rs +++ b/compiler/rustc_infer/src/traits/util.rs @@ -261,9 +261,14 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> { fn elaborate(&mut self, elaboratable: &O) { let tcx = self.visited.tcx; - let bound_predicate = elaboratable.predicate().kind(); - match bound_predicate.skip_binder() { - ty::PredicateKind::Clause(ty::ClauseKind::Trait(data)) => { + // We only elaborate clauses. + let Some(clause) = elaboratable.predicate().as_clause() else { + return; + }; + + let bound_clause = clause.kind(); + match bound_clause.skip_binder() { + ty::ClauseKind::Trait(data) => { // Negative trait bounds do not imply any supertrait bounds if data.polarity == ty::ImplPolarity::Negative { return; @@ -280,52 +285,16 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> { let obligations = predicates.predicates.iter().enumerate().map(|(index, &(clause, span))| { elaboratable.child_with_derived_cause( - clause.subst_supertrait(tcx, &bound_predicate.rebind(data.trait_ref)), + clause.subst_supertrait(tcx, &bound_clause.rebind(data.trait_ref)), span, - bound_predicate.rebind(data), + bound_clause.rebind(data), index, ) }); debug!(?data, ?obligations, "super_predicates"); self.extend_deduped(obligations); } - ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(..)) => { - // Currently, we do not elaborate WF predicates, - // although we easily could. - } - ty::PredicateKind::ObjectSafe(..) => { - // Currently, we do not elaborate object-safe - // predicates. - } - ty::PredicateKind::Subtype(..) => { - // Currently, we do not "elaborate" predicates like `X <: Y`, - // though conceivably we might. - } - ty::PredicateKind::Coerce(..) => { - // Currently, we do not "elaborate" predicates like `X -> Y`, - // though conceivably we might. - } - ty::PredicateKind::Clause(ty::ClauseKind::Projection(..)) => { - // Nothing to elaborate in a projection predicate. - } - ty::PredicateKind::ClosureKind(..) => { - // Nothing to elaborate when waiting for a closure's kind to be inferred. - } - ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..)) => { - // Currently, we do not elaborate const-evaluatable - // predicates. - } - ty::PredicateKind::ConstEquate(..) => { - // Currently, we do not elaborate const-equate - // predicates. - } - ty::PredicateKind::Clause(ty::ClauseKind::RegionOutlives(..)) => { - // Nothing to elaborate from `'a: 'b`. - } - ty::PredicateKind::Clause(ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate( - ty_max, - r_min, - ))) => { + ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(ty_max, r_min)) => { // We know that `T: 'a` for some type `T`. We can // often elaborate this. For example, if we know that // `[U]: 'a`, that implies that `U: 'a`. Similarly, if @@ -340,7 +309,7 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> { // consider this as evidence that `T: 'static`, but // I'm a bit wary of such constructions and so for now // I want to be conservative. --nmatsakis - if r_min.is_late_bound() { + if r_min.is_bound() { return; } @@ -351,7 +320,7 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> { .into_iter() .filter_map(|component| match component { Component::Region(r) => { - if r.is_late_bound() { + if r.is_bound() { None } else { Some(ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate( @@ -365,6 +334,11 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> { Some(ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(ty, r_min))) } + Component::Placeholder(p) => { + let ty = Ty::new_placeholder(tcx, p); + Some(ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(ty, r_min))) + } + Component::UnresolvedInferenceVariable(_) => None, Component::Alias(alias_ty) => { @@ -383,15 +357,25 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> { } }) .map(|clause| { - elaboratable.child(bound_predicate.rebind(clause).to_predicate(tcx)) + elaboratable.child(bound_clause.rebind(clause).to_predicate(tcx)) }), ); } - ty::PredicateKind::Ambiguous => {} - ty::PredicateKind::AliasRelate(..) => { - // No + ty::ClauseKind::RegionOutlives(..) => { + // Nothing to elaborate from `'a: 'b`. + } + ty::ClauseKind::WellFormed(..) => { + // Currently, we do not elaborate WF predicates, + // although we easily could. + } + ty::ClauseKind::Projection(..) => { + // Nothing to elaborate in a projection predicate. + } + ty::ClauseKind::ConstEvaluatable(..) => { + // Currently, we do not elaborate const-evaluatable + // predicates. } - ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(..)) => { + ty::ClauseKind::ConstArgHasType(..) => { // Nothing to elaborate } } |