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Implement some more predicates

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This commit is contained in:
Michael Goulet 2023-01-20 03:05:06 +00:00
parent 2489889231
commit d6a411c086
1 changed files with 57 additions and 7 deletions
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64
compiler/rustc_trait_selection/src/solve/mod.rs
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@ -26,7 +26,9 @@ use rustc_infer::traits::query::NoSolution;
use rustc_infer::traits::Obligation;
use rustc_middle::infer::canonical::Certainty as OldCertainty;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_middle::ty::{RegionOutlivesPredicate, ToPredicate, TypeOutlivesPredicate};
use rustc_middle::ty::{
RegionOutlivesPredicate, SubtypePredicate, ToPredicate, TypeOutlivesPredicate,
};
use rustc_span::DUMMY_SP;
use crate::traits::ObligationCause;
@ -243,16 +245,34 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
ty::PredicateKind::Clause(ty::Clause::RegionOutlives(predicate)) => {
self.compute_region_outlives_goal(Goal { param_env, predicate })
}
ty::PredicateKind::Subtype(predicate) => {
self.compute_subtype_goal(Goal { param_env, predicate })
}
ty::PredicateKind::Coerce(predicate) => self.compute_subtype_goal(Goal {
param_env,
predicate: SubtypePredicate {
a_is_expected: true,
a: predicate.a,
b: predicate.b,
},
}),
ty::PredicateKind::ClosureKind(_, substs, kind) => self.compute_closure_kind_goal(
substs.as_closure().kind_ty().to_opt_closure_kind(),
kind,
),
ty::PredicateKind::Ambiguous => {
self.make_canonical_response(Certainty::Maybe(MaybeCause::Ambiguity))
}
// FIXME: implement these predicates :)
ty::PredicateKind::WellFormed(_)
| ty::PredicateKind::ObjectSafe(_)
| ty::PredicateKind::ClosureKind(_, _, _)
| ty::PredicateKind::Subtype(_)
| ty::PredicateKind::Coerce(_)
| ty::PredicateKind::ConstEvaluatable(_)
| ty::PredicateKind::ConstEquate(_, _)
| ty::PredicateKind::TypeWellFormedFromEnv(_)
| ty::PredicateKind::Ambiguous => self.make_canonical_response(Certainty::Yes),
| ty::PredicateKind::ConstEquate(_, _) => {
self.make_canonical_response(Certainty::Yes)
}
ty::PredicateKind::TypeWellFormedFromEnv(..) => {
bug!("TypeWellFormedFromEnv is only used for Chalk")
}
}
} else {
let kind = self.infcx.replace_bound_vars_with_placeholders(kind);
@ -275,6 +295,36 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
) -> QueryResult<'tcx> {
self.make_canonical_response(Certainty::Yes)
}
fn compute_subtype_goal(
&mut self,
goal: Goal<'tcx, SubtypePredicate<'tcx>>,
) -> QueryResult<'tcx> {
self.infcx.probe(|_| {
let InferOk { value: (), obligations } = self
.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.sub(goal.predicate.a, goal.predicate.b)?;
self.evaluate_all_and_make_canonical_response(
obligations.into_iter().map(|pred| pred.into()).collect(),
)
})
}
fn compute_closure_kind_goal(
&mut self,
found_kind: Option<ty::ClosureKind>,
expected_kind: ty::ClosureKind,
) -> QueryResult<'tcx> {
let Some(found_kind) = found_kind else {
return self.make_canonical_response(Certainty::Maybe(MaybeCause::Ambiguity));
};
if found_kind.extends(expected_kind) {
self.make_canonical_response(Certainty::Yes)
} else {
Err(NoSolution)
}
}
}
impl<'tcx> EvalCtxt<'_, 'tcx> {