bjoernager/rust
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Discard overflow obligations in impl_may_apply

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This commit is contained in:
Michael Goulet 2024-04-07 23:02:28 -04:00
parent f65f84feb0
commit 87a387a722
4 changed files with 55 additions and 6 deletions
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20
compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
View file

@ -5,6 +5,7 @@ use rustc_infer::traits::{Obligation, ObligationCause, PolyTraitObligation};
use rustc_middle::ty;
use rustc_span::{Span, DUMMY_SP};
use crate::traits::query::evaluate_obligation::InferCtxtExt;
use crate::traits::ObligationCtxt;
#[derive(Debug)]
@ -52,10 +53,21 @@ pub fn compute_applicable_impls_for_diagnostics<'tcx>(
_ => return false,
}
let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_args);
ocx.register_obligations(impl_predicates.predicates.iter().map(|&predicate| {
Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate)
}));
let obligations = tcx
.predicates_of(impl_def_id)
.instantiate(tcx, impl_args)
.into_iter()
.map(|(predicate, _)| {
Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate)
})
// Kinda hacky, but let's just throw away obligations that overflow.
// This may reduce the accuracy of this check (if the obligation guides
// inference or it actually resulted in error after others are processed)
// ... but this is diagnostics code.
.filter(|obligation| {
infcx.next_trait_solver() || infcx.evaluate_obligation(obligation).is_ok()
});
ocx.register_obligations(obligations);
ocx.select_where_possible().is_empty()
})

4
compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
View file

@ -2398,12 +2398,12 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
if ambiguities.len() > 5 {
let infcx = self.infcx;
if !ambiguities.iter().all(|option| match option {
DefId(did) => infcx.fresh_args_for_item(DUMMY_SP, *did).is_empty(),
DefId(did) => infcx.tcx.generics_of(*did).count() == 0,
ParamEnv(_) => true,
}) {
// If not all are blanket impls, we filter blanked impls out.
ambiguities.retain(|option| match option {
DefId(did) => infcx.fresh_args_for_item(DUMMY_SP, *did).is_empty(),
DefId(did) => infcx.tcx.generics_of(*did).count() == 0,
ParamEnv(_) => true,
});
}