diff options
| -rw-r--r-- | compiler/rustc_borrowck/src/polonius/liveness_constraints.rs | 29 | ||||
| -rw-r--r-- | compiler/rustc_borrowck/src/universal_regions.rs | 2 |
2 files changed, 24 insertions, 7 deletions
diff --git a/compiler/rustc_borrowck/src/polonius/liveness_constraints.rs b/compiler/rustc_borrowck/src/polonius/liveness_constraints.rs index 950fef27286..75ee29c9d0d 100644 --- a/compiler/rustc_borrowck/src/polonius/liveness_constraints.rs +++ b/compiler/rustc_borrowck/src/polonius/liveness_constraints.rs @@ -231,17 +231,34 @@ struct VarianceExtractor<'a, 'tcx> { impl<'tcx> VarianceExtractor<'_, 'tcx> { fn record_variance(&mut self, region: ty::Region<'tcx>, variance: ty::Variance) { // We're only interested in the variance of vars and free regions. + // + // Note: even if we currently bail for two cases of unexpected region kinds here, missing + // variance data is not a soundness problem: the regions with missing variance will still be + // present in the constraint graph as they are live, and liveness edges construction has a + // fallback for this case. + // + // FIXME: that being said, we need to investigate these cases better to not ignore regions + // in general. + if region.is_bound() { + // We ignore these because they cannot be turned into the vids we need. + return; + } - if region.is_bound() || region.is_erased() { - // ignore these + if region.is_erased() { + // These cannot be turned into a vid either, and we also ignore them: the fact that they + // show up here looks like either an issue upstream or a combination with unexpectedly + // continuing compilation too far when we're in a tainted by errors situation. + // + // FIXME: investigate the `generic_const_exprs` test that triggers this issue, + // `ui/const-generics/generic_const_exprs/issue-97047-ice-2.rs` return; } let direction = match variance { - ty::Variance::Covariant => ConstraintDirection::Forward, - ty::Variance::Contravariant => ConstraintDirection::Backward, - ty::Variance::Invariant => ConstraintDirection::Bidirectional, - ty::Variance::Bivariant => { + ty::Covariant => ConstraintDirection::Forward, + ty::Contravariant => ConstraintDirection::Backward, + ty::Invariant => ConstraintDirection::Bidirectional, + ty::Bivariant => { // We don't add edges for bivariant cases. return; } diff --git a/compiler/rustc_borrowck/src/universal_regions.rs b/compiler/rustc_borrowck/src/universal_regions.rs index 1ac45cbea38..3dc4569c57b 100644 --- a/compiler/rustc_borrowck/src/universal_regions.rs +++ b/compiler/rustc_borrowck/src/universal_regions.rs @@ -337,7 +337,7 @@ impl<'tcx> UniversalRegions<'tcx> { self.indices.indices.iter().map(|(&r, &v)| (r, v)) } - /// See `UniversalRegionIndices::to_region_vid`. + /// See [UniversalRegionIndices::to_region_vid]. pub(crate) fn to_region_vid(&self, r: ty::Region<'tcx>) -> RegionVid { self.indices.to_region_vid(r) } |