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-Zhigher-ranked-assumptions
: Consider WF of coroutine witness when proving outlives assumptions
#143545
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-Zhigher-ranked-assumptions
: Consider WF of coroutine witness when proving outlives assumptions
#143545
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Original file line number | Diff line number | Diff line change |
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@@ -1,5 +1,10 @@ | ||
use rustc_hir::def_id::DefId; | ||
use rustc_middle::ty::{self, TyCtxt, fold_regions}; | ||
use rustc_infer::infer::TyCtxtInferExt; | ||
use rustc_infer::infer::canonical::query_response::make_query_region_constraints; | ||
use rustc_infer::infer::resolve::OpportunisticRegionResolver; | ||
use rustc_infer::traits::{Obligation, ObligationCause}; | ||
use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeVisitableExt, fold_regions}; | ||
use rustc_trait_selection::traits::{ObligationCtxt, with_replaced_escaping_bound_vars}; | ||
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/// Return the set of types that should be taken into account when checking | ||
/// trait bounds on a coroutine's internal state. This properly replaces | ||
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@@ -30,8 +35,55 @@ pub(crate) fn coroutine_hidden_types<'tcx>( | |
}), | ||
); | ||
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let assumptions = compute_assumptions(tcx, def_id, bound_tys); | ||
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ty::EarlyBinder::bind(ty::Binder::bind_with_vars( | ||
ty::CoroutineWitnessTypes { types: bound_tys }, | ||
ty::CoroutineWitnessTypes { types: bound_tys, assumptions }, | ||
tcx.mk_bound_variable_kinds(&vars), | ||
)) | ||
} | ||
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||
fn compute_assumptions<'tcx>( | ||
tcx: TyCtxt<'tcx>, | ||
def_id: DefId, | ||
bound_tys: &'tcx ty::List<Ty<'tcx>>, | ||
) -> &'tcx ty::List<ty::OutlivesPredicate<'tcx, ty::GenericArg<'tcx>>> { | ||
let infcx = tcx.infer_ctxt().build(ty::TypingMode::Analysis { | ||
defining_opaque_types_and_generators: ty::List::empty(), | ||
}); | ||
with_replaced_escaping_bound_vars(&infcx, &mut vec![None], bound_tys, |bound_tys| { | ||
let param_env = tcx.param_env(def_id); | ||
let ocx = ObligationCtxt::new(&infcx); | ||
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ocx.register_obligations(bound_tys.iter().map(|ty| { | ||
Obligation::new( | ||
tcx, | ||
ObligationCause::dummy(), | ||
param_env, | ||
ty::ClauseKind::WellFormed(ty.into()), | ||
) | ||
})); | ||
let _errors = ocx.select_all_or_error(); | ||
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let region_obligations = infcx.take_registered_region_obligations(); | ||
let region_constraints = infcx.take_and_reset_region_constraints(); | ||
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let outlives = make_query_region_constraints( | ||
tcx, | ||
region_obligations, | ||
®ion_constraints, | ||
) | ||
.outlives | ||
.fold_with(&mut OpportunisticRegionResolver::new(&infcx)); | ||
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tcx.mk_outlives_from_iter( | ||
outlives | ||
.into_iter() | ||
.map(|(o, _)| o) | ||
// FIXME(higher_ranked_auto): We probably should deeply resolve these before | ||
// filtering out infers which only correspond to unconstrained infer regions | ||
// which we can sometimes get. | ||
.filter(|o| !o.has_infer()), | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. The idea here is that all regions in There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. e.g., There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Probably not, but I would be surprised if that's unsound, since we'd already be on the hook to prove a similar obligation when checking the coroutine itself. |
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) | ||
}) | ||
} |
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