Rollup merge of #120155 - compiler-errors:no-erased-when-promoting, r=aliemjay

Don't use `ReErased` to detect type test promotion failed

Using `ReErased` here is convenient because it implicitly stores the state that we are explicitly recording with the `failed` variable now, but I also think it adds a tiny bit of complexity that is not worth it.

r? `@aliemjay`
This commit is contained in:
Matthias Krüger 2024-01-20 09:37:30 +01:00 committed by GitHub
commit bb816e67b4
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@ -18,7 +18,7 @@
}; };
use rustc_middle::traits::ObligationCause; use rustc_middle::traits::ObligationCause;
use rustc_middle::traits::ObligationCauseCode; use rustc_middle::traits::ObligationCauseCode;
use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt, TypeFoldable, TypeVisitableExt}; use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt, TypeFoldable};
use rustc_mir_dataflow::points::DenseLocationMap; use rustc_mir_dataflow::points::DenseLocationMap;
use rustc_span::Span; use rustc_span::Span;
@ -1145,6 +1145,7 @@ fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
} }
let ty = ty.fold_with(&mut OpaqueFolder { tcx }); let ty = ty.fold_with(&mut OpaqueFolder { tcx });
let mut failed = false;
let ty = tcx.fold_regions(ty, |r, _depth| { let ty = tcx.fold_regions(ty, |r, _depth| {
let r_vid = self.to_region_vid(r); let r_vid = self.to_region_vid(r);
@ -1160,15 +1161,18 @@ fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
.filter(|&u_r| !self.universal_regions.is_local_free_region(u_r)) .filter(|&u_r| !self.universal_regions.is_local_free_region(u_r))
.find(|&u_r| self.eval_equal(u_r, r_vid)) .find(|&u_r| self.eval_equal(u_r, r_vid))
.map(|u_r| ty::Region::new_var(tcx, u_r)) .map(|u_r| ty::Region::new_var(tcx, u_r))
// In the case of a failure, use `ReErased`. We will eventually // In case we could not find a named region to map to,
// return `None` in this case. // we will return `None` below.
.unwrap_or(tcx.lifetimes.re_erased) .unwrap_or_else(|| {
failed = true;
r
})
}); });
debug!("try_promote_type_test_subject: folded ty = {:?}", ty); debug!("try_promote_type_test_subject: folded ty = {:?}", ty);
// This will be true if we failed to promote some region. // This will be true if we failed to promote some region.
if ty.has_erased_regions() { if failed {
return None; return None;
} }