bjoernager/rust
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Add trait obligation tracking to FulfillCtxt and expose FnCtxt in rustc_infer using callback.

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Pass each obligation to an fn callback with its respective inference context. This avoids needing to keep around copies of obligations or inference contexts.

Specify usability of inspect_typeck in comment.
This commit is contained in:
Gavin Gray 2023-11-21 20:37:36 +01:00 • committed by gavinleroy
parent 2457c028c9
commit 130b7e713e
5 changed files with 121 additions and 64 deletions
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136
compiler/rustc_trait_selection/src/solve/fulfill.rs
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@ -11,7 +11,7 @@ use rustc_middle::ty;
use rustc_middle::ty::error::{ExpectedFound, TypeError};
use super::eval_ctxt::GenerateProofTree;
use super::{Certainty, InferCtxtEvalExt};
use super::{Certainty, Goal, InferCtxtEvalExt};
/// A trait engine using the new trait solver.
///
@ -43,6 +43,21 @@ impl<'tcx> FulfillmentCtxt<'tcx> {
);
FulfillmentCtxt { obligations: Vec::new(), usable_in_snapshot: infcx.num_open_snapshots() }
}
fn inspect_evaluated_obligation(
&self,
infcx: &InferCtxt<'tcx>,
obligation: &PredicateObligation<'tcx>,
result: &Result<(bool, Certainty, Vec<Goal<'tcx, ty::Predicate<'tcx>>>), NoSolution>,
) {
if let Some(inspector) = infcx.obligation_inspector.get() {
let result = match result {
Ok((_, c, _)) => Ok(*c),
Err(NoSolution) => Err(NoSolution),
};
(inspector)(infcx, &obligation, result);
}
}
}
impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
@ -100,65 +115,66 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
let mut has_changed = false;
for obligation in mem::take(&mut self.obligations) {
let goal = obligation.clone().into();
let (changed, certainty, nested_goals) =
match infcx.evaluate_root_goal(goal, GenerateProofTree::IfEnabled).0 {
Ok(result) => result,
Err(NoSolution) => {
errors.push(FulfillmentError {
obligation: obligation.clone(),
code: match goal.predicate.kind().skip_binder() {
ty::PredicateKind::Clause(ty::ClauseKind::Projection(_)) => {
FulfillmentErrorCode::ProjectionError(
// FIXME: This could be a `Sorts` if the term is a type
MismatchedProjectionTypes { err: TypeError::Mismatch },
)
}
ty::PredicateKind::NormalizesTo(..) => {
FulfillmentErrorCode::ProjectionError(
MismatchedProjectionTypes { err: TypeError::Mismatch },
)
}
ty::PredicateKind::AliasRelate(_, _, _) => {
FulfillmentErrorCode::ProjectionError(
MismatchedProjectionTypes { err: TypeError::Mismatch },
)
}
ty::PredicateKind::Subtype(pred) => {
let (a, b) = infcx.instantiate_binder_with_placeholders(
goal.predicate.kind().rebind((pred.a, pred.b)),
);
let expected_found = ExpectedFound::new(true, a, b);
FulfillmentErrorCode::SubtypeError(
expected_found,
TypeError::Sorts(expected_found),
)
}
ty::PredicateKind::Coerce(pred) => {
let (a, b) = infcx.instantiate_binder_with_placeholders(
goal.predicate.kind().rebind((pred.a, pred.b)),
);
let expected_found = ExpectedFound::new(false, a, b);
FulfillmentErrorCode::SubtypeError(
expected_found,
TypeError::Sorts(expected_found),
)
}
ty::PredicateKind::Clause(_)
| ty::PredicateKind::ObjectSafe(_)
| ty::PredicateKind::Ambiguous => {
FulfillmentErrorCode::SelectionError(
SelectionError::Unimplemented,
)
}
ty::PredicateKind::ConstEquate(..) => {
bug!("unexpected goal: {goal:?}")
}
},
root_obligation: obligation,
});
continue;
}
};
let result = infcx.evaluate_root_goal(goal, GenerateProofTree::IfEnabled).0;
self.inspect_evaluated_obligation(infcx, &obligation, &result);
let (changed, certainty, nested_goals) = match result {
Ok(result) => result,
Err(NoSolution) => {
errors.push(FulfillmentError {
obligation: obligation.clone(),
code: match goal.predicate.kind().skip_binder() {
ty::PredicateKind::Clause(ty::ClauseKind::Projection(_)) => {
FulfillmentErrorCode::ProjectionError(
// FIXME: This could be a `Sorts` if the term is a type
MismatchedProjectionTypes { err: TypeError::Mismatch },
)
}
ty::PredicateKind::NormalizesTo(..) => {
FulfillmentErrorCode::ProjectionError(
MismatchedProjectionTypes { err: TypeError::Mismatch },
)
}
ty::PredicateKind::AliasRelate(_, _, _) => {
FulfillmentErrorCode::ProjectionError(
MismatchedProjectionTypes { err: TypeError::Mismatch },
)
}
ty::PredicateKind::Subtype(pred) => {
let (a, b) = infcx.instantiate_binder_with_placeholders(
goal.predicate.kind().rebind((pred.a, pred.b)),
);
let expected_found = ExpectedFound::new(true, a, b);
FulfillmentErrorCode::SubtypeError(
expected_found,
TypeError::Sorts(expected_found),
)
}
ty::PredicateKind::Coerce(pred) => {
let (a, b) = infcx.instantiate_binder_with_placeholders(
goal.predicate.kind().rebind((pred.a, pred.b)),
);
let expected_found = ExpectedFound::new(false, a, b);
FulfillmentErrorCode::SubtypeError(
expected_found,
TypeError::Sorts(expected_found),
)
}
ty::PredicateKind::Clause(_)
| ty::PredicateKind::ObjectSafe(_)
| ty::PredicateKind::Ambiguous => {
FulfillmentErrorCode::SelectionError(
SelectionError::Unimplemented,
)
}
ty::PredicateKind::ConstEquate(..) => {
bug!("unexpected goal: {goal:?}")
}
},
root_obligation: obligation,
});
continue;
}
};
// Push any nested goals that we get from unifying our canonical response
// with our obligation onto the fulfillment context.
self.obligations.extend(nested_goals.into_iter().map(|goal| {