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use rustc::traits::{Normalized, ObligationCause};
use rustc::traits::query::NoSolution;
use rustc::ty::query::Providers;
use rustc::ty::{self, ParamEnvAnd, Ty, TyCtxt};
use std::sync::atomic::Ordering;
crate fn provide(p: &mut Providers) {
*p = Providers {
normalize_ty_after_erasing_regions,
..*p
};
}
fn normalize_ty_after_erasing_regions<'tcx>(
tcx: TyCtxt<'_, 'tcx, 'tcx>,
goal: ParamEnvAnd<'tcx, Ty<'tcx>>,
) -> Ty<'tcx> {
debug!("normalize_ty_after_erasing_regions(goal={:#?})", goal);
let ParamEnvAnd { param_env, value } = goal;
tcx.sess.perf_stats.normalize_ty_after_erasing_regions.fetch_add(1, Ordering::Relaxed);
tcx.infer_ctxt().enter(|infcx| {
let cause = ObligationCause::dummy();
match infcx.at(&cause, param_env).normalize(&value) {
Ok(Normalized {
value: normalized_value,
obligations: normalized_obligations,
}) => {
debug_assert_eq!(
normalized_obligations
.iter()
.find(|p| not_outlives_predicate(&p.predicate)),
None,
);
let normalized_value = infcx.resolve_type_vars_if_possible(&normalized_value);
let normalized_value = infcx.tcx.erase_regions(&normalized_value);
tcx.lift_to_global(&normalized_value).unwrap()
}
Err(NoSolution) => bug!("could not fully normalize `{:?}`", value),
}
})
}
fn not_outlives_predicate(p: &ty::Predicate<'_>) -> bool {
match p {
ty::Predicate::RegionOutlives(..) | ty::Predicate::TypeOutlives(..) => false,
ty::Predicate::Trait(..)
| ty::Predicate::Projection(..)
| ty::Predicate::WellFormed(..)
| ty::Predicate::ObjectSafe(..)
| ty::Predicate::ClosureKind(..)
| ty::Predicate::Subtype(..)
| ty::Predicate::ConstEvaluatable(..) => true,
}
}