subtyping_projections

compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs

@@ -57,6 +57,7 @@ impl<'tcx> Lift for PlaceElem<'tcx> {
                 ProjectionElem::ConstantIndex { offset, min_length, from_end }
             }
             ProjectionElem::Downcast(a, u) => ProjectionElem::Downcast(a, u),
+            ProjectionElem::Subtype(ty) => ProjectionElem::Subtype(ty.lift()),
         }
     }
 }

compiler/rustc_mir_dataflow/src/move_paths/builder.rs

@@ -112,6 +112,9 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
         let mut union_path = None;
 
         for (place_ref, elem) in data.rev_lookup.un_derefer.iter_projections(place.as_ref()) {
+            if elem.is_subtype() {
+                continue;
+            }
             let body = self.builder.body;
             let tcx = self.builder.tcx;
             let place_ty = place_ref.ty(body, tcx).ty;