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Change inference var check to be in project_type

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This commit is contained in:
Jack Huey
2022-01-14 21:21:40 -05:00
parent 3602e0e262
commit 7ad48bd4e2
7 changed files with 27 additions and 32 deletions
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2
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View File

@@ -2470,7 +2470,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let projection_ty = ty::ProjectionTy {
// `T`
substs: self.tcx.mk_substs_trait(
trait_ref.self_ty().skip_binder(),
trait_pred.self_ty().skip_binder(),
&self.fresh_substs_for_item(span, item_def_id)[1..],
),
// `Future::Output`

10
compiler/rustc_trait_selection/src/traits/project.rs
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@@ -1073,6 +1073,16 @@ fn project<'cx, 'tcx>(
return Ok(Projected::Progress(Progress::error(selcx.tcx())));
}
// If the obligation contains any inference types or consts in associated
// type substs, then we don't assemble any candidates.
// This isn't really correct, but otherwise we can end up in a case where
// we constrain inference variables by selecting a single predicate, when
// we need to stay general. See issue #91762.
let (_, predicate_own_substs) = obligation.predicate.trait_ref_and_own_substs(selcx.tcx());
if predicate_own_substs.iter().any(|g| g.has_infer_types_or_consts()) {
return Err(ProjectionError::TooManyCandidates);
}
let mut candidates = ProjectionCandidateSet::None;
// Make sure that the following procedures are kept in order. ParamEnv

10
compiler/rustc_trait_selection/src/traits/select/mod.rs
View File

@@ -1521,16 +1521,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
infer_predicate.projection_ty
};
// If the obligation contains any inference types or consts in associated
// type substs, then we don't match any projection candidates against it.
// This isn't really correct, but otherwise we can end up in a case where
// we constrain inference variables by selecting a single predicate, when
// we need to stay general. See issue #91762.
let (_, predicate_own_substs) =
obligation.predicate.trait_ref_and_own_substs(self.infcx.tcx);
if predicate_own_substs.iter().any(|g| g.has_infer_types_or_consts()) {
return false;
}
self.infcx
.at(&obligation.cause, obligation.param_env)
.sup(obligation.predicate, infer_projection)