bjoernager/rust
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Check for overflow in assemble_candidates_after_normalizing_self_ty

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This commit is contained in:
Michael Goulet 2023-03-27 21:48:43 +00:00
parent bf57e8ada6
commit ef5f773bff
6 changed files with 105 additions and 18 deletions
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50
compiler/rustc_trait_selection/src/solve/assembly.rs
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@ -1,5 +1,6 @@
//! Code shared by trait and projection goals for candidate assembly.
use super::search_graph::OverflowHandler;
#[cfg(doc)]
use super::trait_goals::structural_traits::*;
use super::{EvalCtxt, SolverMode};
@ -279,25 +280,38 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
return
};
self.probe(|ecx| {
let normalized_ty = ecx.next_ty_infer();
let normalizes_to_goal = goal.with(
tcx,
ty::Binder::dummy(ty::ProjectionPredicate {
projection_ty,
term: normalized_ty.into(),
}),
);
ecx.add_goal(normalizes_to_goal);
if let Ok(_) = ecx.try_evaluate_added_goals() {
let normalized_ty = ecx.resolve_vars_if_possible(normalized_ty);
// NOTE: Alternatively we could call `evaluate_goal` here and only have a `Normalized` candidate.
// This doesn't work as long as we use `CandidateSource` in winnowing.
let goal = goal.with(tcx, goal.predicate.with_self_ty(tcx, normalized_ty));
candidates.extend(ecx.assemble_and_evaluate_candidates(goal));
}
let normalized_self_candidates: Result<_, NoSolution> = self.probe(|ecx| {
ecx.with_incremented_depth(
|ecx| {
let result = ecx.evaluate_added_goals_and_make_canonical_response(
Certainty::Maybe(MaybeCause::Overflow),
)?;
Ok(vec![Candidate { source: CandidateSource::BuiltinImpl, result }])
},
|ecx| {
let normalized_ty = ecx.next_ty_infer();
let normalizes_to_goal = goal.with(
tcx,
ty::Binder::dummy(ty::ProjectionPredicate {
projection_ty,
term: normalized_ty.into(),
}),
);
ecx.add_goal(normalizes_to_goal);
let _ = ecx.try_evaluate_added_goals()?;
let normalized_ty = ecx.resolve_vars_if_possible(normalized_ty);
// NOTE: Alternatively we could call `evaluate_goal` here and only
// have a `Normalized` candidate. This doesn't work as long as we
// use `CandidateSource` in winnowing.
let goal = goal.with(tcx, goal.predicate.with_self_ty(tcx, normalized_ty));
Ok(ecx.assemble_and_evaluate_candidates(goal))
},
)
});
if let Ok(normalized_self_candidates) = normalized_self_candidates {
candidates.extend(normalized_self_candidates);
}
}
fn assemble_impl_candidates<G: GoalKind<'tcx>>(