diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src/validate.rs')
| -rw-r--r-- | compiler/rustc_mir_transform/src/validate.rs | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/compiler/rustc_mir_transform/src/validate.rs b/compiler/rustc_mir_transform/src/validate.rs index 66cc65de647..6df32169eec 100644 --- a/compiler/rustc_mir_transform/src/validate.rs +++ b/compiler/rustc_mir_transform/src/validate.rs @@ -689,8 +689,10 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { if Some(adt_def.did()) == self.tcx.lang_items().dyn_metadata() { self.fail( location, - format!("You can't project to field {f:?} of `DynMetadata` because \ - layout is weird and thinks it doesn't have fields."), + format!( + "You can't project to field {f:?} of `DynMetadata` because \ + layout is weird and thinks it doesn't have fields." + ), ); } @@ -839,7 +841,25 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { && cntxt != PlaceContext::NonUse(NonUseContext::VarDebugInfo) && place.projection[1..].contains(&ProjectionElem::Deref) { - self.fail(location, format!("{place:?}, has deref at the wrong place")); + self.fail( + location, + format!("place {place:?} has deref as a later projection (it is only permitted as the first projection)"), + ); + } + + // Ensure all downcast projections are followed by field projections. + let mut projections_iter = place.projection.iter(); + while let Some(proj) = projections_iter.next() { + if matches!(proj, ProjectionElem::Downcast(..)) { + if !matches!(projections_iter.next(), Some(ProjectionElem::Field(..))) { + self.fail( + location, + format!( + "place {place:?} has `Downcast` projection not followed by `Field`" + ), + ); + } + } } self.super_place(place, cntxt, location); |