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separate calculation and interning of external query constraints

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This commit is contained in:
Michael Goulet 2023-08-02 00:43:35 +00:00
parent defed6257a
commit 5bea48ba18
1 changed files with 28 additions and 27 deletions
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55
compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs
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@ -18,7 +18,7 @@ use rustc_infer::infer::canonical::CanonicalVarValues;
use rustc_infer::infer::canonical::{CanonicalExt, QueryRegionConstraints};
use rustc_middle::traits::query::NoSolution;
use rustc_middle::traits::solve::{
ExternalConstraints, ExternalConstraintsData, MaybeCause, PredefinedOpaquesData, QueryInput,
ExternalConstraintsData, MaybeCause, PredefinedOpaquesData, QueryInput,
};
use rustc_middle::ty::{self, BoundVar, GenericArgKind, Ty, TyCtxt, TypeFoldable};
use rustc_span::DUMMY_SP;
@ -69,35 +69,36 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
previous call to `try_evaluate_added_goals!`"
);
let certainty = certainty.unify_with(goals_certainty);
if let Certainty::OVERFLOW = certainty {
// If we have overflow, it's probable that we're substituting a type
// into itself infinitely and any partial substitutions in the query
// response are probably not useful anyways, so just return an empty
// query response.
//
// This may prevent us from potentially useful inference, e.g.
// 2 candidates, one ambiguous and one overflow, which both
// have the same inference constraints.
//
// Changing this to retain some constraints in the future
// won't be a breaking change, so this is good enough for now.
return Ok(self.make_ambiguous_response_no_constraints(MaybeCause::Overflow));
}
let response = match certainty {
Certainty::Yes | Certainty::Maybe(MaybeCause::Ambiguity) => {
let external_constraints = self.compute_external_query_constraints()?;
Response { var_values: self.var_values, external_constraints, certainty }
}
Certainty::Maybe(MaybeCause::Overflow) => {
// If we have overflow, it's probable that we're substituting a type
// into itself infinitely and any partial substitutions in the query
// response are probably not useful anyways, so just return an empty
// query response.
//
// This may prevent us from potentially useful inference, e.g.
// 2 candidates, one ambiguous and one overflow, which both
// have the same inference constraints.
//
// Changing this to retain some constraints in the future
// won't be a breaking change, so this is good enough for now.
return Ok(self.make_ambiguous_response_no_constraints(MaybeCause::Overflow));
}
};
let certainty = certainty.unify_with(goals_certainty);
let var_values = self.var_values;
let external_constraints = self.compute_external_query_constraints()?;
let canonical = Canonicalizer::canonicalize(
self.infcx,
CanonicalizeMode::Response { max_input_universe: self.max_input_universe },
&mut Default::default(),
response,
Response {
var_values,
certainty,
external_constraints: self.tcx().mk_external_constraints(external_constraints),
},
);
Ok(canonical)
}
@ -143,7 +144,9 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
/// further constrained by inference, that will be passed back in the var
/// values.
#[instrument(level = "debug", skip(self), ret)]
fn compute_external_query_constraints(&self) -> Result<ExternalConstraints<'tcx>, NoSolution> {
fn compute_external_query_constraints(
&self,
) -> Result<ExternalConstraintsData<'tcx>, NoSolution> {
// We only check for leaks from universes which were entered inside
// of the query.
self.infcx.leak_check(self.max_input_universe, None).map_err(|e| {
@ -173,9 +176,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
self.predefined_opaques_in_body.opaque_types.iter().all(|(pa, _)| pa != a)
});
Ok(self
.tcx()
.mk_external_constraints(ExternalConstraintsData { region_constraints, opaque_types }))
Ok(ExternalConstraintsData { region_constraints, opaque_types })
}
/// After calling a canonical query, we apply the constraints returned