bjoernager/rust
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Remove AliasRelationDirection::Supertype

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This commit is contained in:
Michael Goulet 2023-03-22 16:58:51 +00:00
parent f6fd754680
commit 244cdaa457
5 changed files with 98 additions and 90 deletions
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19
compiler/rustc_trait_selection/src/solve/eval_ctxt.rs
View file

@ -459,6 +459,25 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
})
}
#[instrument(level = "debug", skip(self, param_env), ret)]
pub(super) fn sub<T: ToTrace<'tcx>>(
&mut self,
param_env: ty::ParamEnv<'tcx>,
sub: T,
sup: T,
) -> Result<(), NoSolution> {
self.infcx
.at(&ObligationCause::dummy(), param_env)
.sub(DefineOpaqueTypes::No, sub, sup)
.map(|InferOk { value: (), obligations }| {
self.add_goals(obligations.into_iter().map(|o| o.into()));
})
.map_err(|e| {
debug!(?e, "failed to subtype");
NoSolution
})
}
/// Equates two values returning the nested goals without adding them
/// to the nested goals of the `EvalCtxt`.
///

115
compiler/rustc_trait_selection/src/solve/mod.rs
View file

@ -17,7 +17,6 @@
use rustc_hir::def_id::DefId;
use rustc_infer::infer::canonical::{Canonical, CanonicalVarValues};
use rustc_infer::infer::{DefineOpaqueTypes, InferOk};
use rustc_infer::traits::query::NoSolution;
use rustc_middle::traits::solve::{
CanonicalGoal, CanonicalResponse, Certainty, ExternalConstraints, ExternalConstraintsData,
@ -101,11 +100,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
// That won't actually reflect in the query response, so it seems moot.
self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
} else {
let InferOk { value: (), obligations } = self
.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.sub(DefineOpaqueTypes::No, goal.predicate.a, goal.predicate.b)?;
self.add_goals(obligations.into_iter().map(|pred| pred.into()));
self.sub(goal.param_env, goal.predicate.a, goal.predicate.b)?;
self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
}
}
@ -161,44 +156,41 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
goal: Goal<'tcx, (ty::Term<'tcx>, ty::Term<'tcx>, ty::AliasRelationDirection)>,
) -> QueryResult<'tcx> {
let tcx = self.tcx();
// We may need to invert the alias relation direction if dealing an alias on the RHS.
enum Invert {
No,
Yes,
}
let evaluate_normalizes_to =
|ecx: &mut EvalCtxt<'_, 'tcx>, alias, other, direction, invert| {
debug!("evaluate_normalizes_to(alias={:?}, other={:?})", alias, other);
let result = ecx.probe(|ecx| {
let other = match direction {
// This is purely an optimization.
ty::AliasRelationDirection::Equate => other,
let evaluate_normalizes_to = |ecx: &mut EvalCtxt<'_, 'tcx>, alias, other, direction| {
debug!("evaluate_normalizes_to(alias={:?}, other={:?})", alias, other);
let result = ecx.probe(|ecx| {
let other = match direction {
// This is purely an optimization.
ty::AliasRelationDirection::Equate => other,
ty::AliasRelationDirection::Subtype | ty::AliasRelationDirection::Supertype => {
let fresh = ecx.next_term_infer_of_kind(other);
let (sub, sup) = if direction == ty::AliasRelationDirection::Subtype {
(fresh, other)
} else {
(other, fresh)
};
ecx.add_goals(
ecx.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.sub(DefineOpaqueTypes::No, sub, sup)?
.into_obligations()
.into_iter()
.map(|o| o.into()),
);
fresh
}
};
ecx.add_goal(goal.with(
tcx,
ty::Binder::dummy(ty::ProjectionPredicate {
projection_ty: alias,
term: other,
}),
));
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
});
debug!("evaluate_normalizes_to({alias}, {other}, {direction:?}) -> {result:?}");
result
};
ty::AliasRelationDirection::Subtype => {
let fresh = ecx.next_term_infer_of_kind(other);
let (sub, sup) = match invert {
Invert::No => (fresh, other),
Invert::Yes => (other, fresh),
};
ecx.sub(goal.param_env, sub, sup)?;
fresh
}
};
ecx.add_goal(goal.with(
tcx,
ty::Binder::dummy(ty::ProjectionPredicate {
projection_ty: alias,
term: other,
}),
));
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
});
debug!("evaluate_normalizes_to({alias}, {other}, {direction:?}) -> {result:?}");
result
};
let (lhs, rhs, direction) = goal.predicate;
@ -212,11 +204,13 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
(None, None) => bug!("`AliasRelate` goal without an alias on either lhs or rhs"),
// RHS is not a projection, only way this is true is if LHS normalizes-to RHS
(Some(alias_lhs), None) => evaluate_normalizes_to(self, alias_lhs, rhs, direction),
(Some(alias_lhs), None) => {
evaluate_normalizes_to(self, alias_lhs, rhs, direction, Invert::No)
}
// LHS is not a projection, only way this is true is if RHS normalizes-to LHS
(None, Some(alias_rhs)) => {
evaluate_normalizes_to(self, alias_rhs, lhs, direction.invert())
evaluate_normalizes_to(self, alias_rhs, lhs, direction, Invert::Yes)
}
(Some(alias_lhs), Some(alias_rhs)) => {
@ -224,34 +218,23 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
let candidates = vec![
// LHS normalizes-to RHS
evaluate_normalizes_to(self, alias_lhs, rhs, direction),
evaluate_normalizes_to(self, alias_lhs, rhs, direction, Invert::No),
// RHS normalizes-to RHS
evaluate_normalizes_to(self, alias_rhs, lhs, direction.invert()),
evaluate_normalizes_to(self, alias_rhs, lhs, direction, Invert::Yes),
// Relate via substs
self.probe(|ecx| {
debug!(
"compute_alias_relate_goal: alias defids are equal, equating substs"
);
ecx.add_goals(
match direction {
ty::AliasRelationDirection::Equate => ecx
.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.eq(DefineOpaqueTypes::No, alias_lhs, alias_rhs),
ty::AliasRelationDirection::Subtype => ecx
.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.sub(DefineOpaqueTypes::No, alias_lhs, alias_rhs),
ty::AliasRelationDirection::Supertype => ecx
.infcx
.at(&ObligationCause::dummy(), goal.param_env)
.sup(DefineOpaqueTypes::No, alias_lhs, alias_rhs),
}?
.into_obligations()
.into_iter()
.map(|o| o.into()),
);
match direction {
ty::AliasRelationDirection::Equate => {
ecx.eq(goal.param_env, alias_lhs, alias_rhs)?;
}
ty::AliasRelationDirection::Subtype => {
ecx.sub(goal.param_env, alias_lhs, alias_rhs)?;
}
}
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
}),