7 files changed, 19 insertions, 1 deletions
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index cfd794e9e00..ee352e911d3 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -2827,6 +2827,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         }
                         ProjectionElem::ConstantIndex { .. }
                         | ProjectionElem::Subslice { .. }
+                        | ProjectionElem::Subtype(_)
                         | ProjectionElem::Index(_) => kind,
                     },
                     place_ty.projection_ty(tcx, elem),
diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index 8c4fa917f9d..8d4028de90d 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -242,6 +242,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 ProjectionElem::Downcast(..) if opt.including_downcast => return None,
                 ProjectionElem::Downcast(..) => (),
                 ProjectionElem::OpaqueCast(..) => (),
+                ProjectionElem::Subtype(..) => (),
                 ProjectionElem::Field(field, _ty) => {
                     // FIXME(project-rfc_2229#36): print capture precisely here.
                     if let Some(field) = self.is_upvar_field_projection(PlaceRef {
@@ -322,7 +323,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     PlaceRef { local, projection: proj_base }.ty(self.body, self.infcx.tcx)
                 }
                 ProjectionElem::Downcast(..) => place.ty(self.body, self.infcx.tcx),
-                ProjectionElem::OpaqueCast(ty) => PlaceTy::from_ty(*ty),
+                ProjectionElem::Subtype(ty) | ProjectionElem::OpaqueCast(ty) => {
+                    PlaceTy::from_ty(*ty)
+                }
                 ProjectionElem::Field(_, field_type) => PlaceTy::from_ty(*field_type),
             },
         };
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index a0edeec59d0..8ca57383e82 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -159,6 +159,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     [
                         ..,
                         ProjectionElem::Index(_)
+                        | ProjectionElem::Subtype(_)
                         | ProjectionElem::ConstantIndex { .. }
                         | ProjectionElem::OpaqueCast { .. }
                         | ProjectionElem::Subslice { .. }
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index abf9811c50b..1d17df8b79a 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -1803,6 +1803,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         for (place_base, elem) in place.iter_projections().rev() {
             match elem {
                 ProjectionElem::Index(_/*operand*/) |
+                ProjectionElem::Subtype(_) |
                 ProjectionElem::OpaqueCast(_) |
                 ProjectionElem::ConstantIndex { .. } |
                 // assigning to P[i] requires P to be valid.
@@ -2191,6 +2192,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     | ProjectionElem::Index(..)
                     | ProjectionElem::ConstantIndex { .. }
                     | ProjectionElem::Subslice { .. }
+                    | ProjectionElem::Subtype(..)
                     | ProjectionElem::OpaqueCast { .. }
                     | ProjectionElem::Downcast(..) => {
                         let upvar_field_projection = self.is_upvar_field_projection(place);
diff --git a/compiler/rustc_borrowck/src/places_conflict.rs b/compiler/rustc_borrowck/src/places_conflict.rs
index a0fcdcd1f5e..777ebf0d438 100644
--- a/compiler/rustc_borrowck/src/places_conflict.rs
+++ b/compiler/rustc_borrowck/src/places_conflict.rs
@@ -249,6 +249,7 @@ fn place_components_conflict<'tcx>(
                 | (ProjectionElem::ConstantIndex { .. }, _, _)
                 | (ProjectionElem::Subslice { .. }, _, _)
                 | (ProjectionElem::OpaqueCast { .. }, _, _)
+                | (ProjectionElem::Subtype(_), _, _)
                 | (ProjectionElem::Downcast { .. }, _, _) => {
                     // Recursive case. This can still be disjoint on a
                     // further iteration if this a shallow access and
@@ -508,6 +509,7 @@ fn place_projection_conflict<'tcx>(
             | ProjectionElem::Field(..)
             | ProjectionElem::Index(..)
             | ProjectionElem::ConstantIndex { .. }
+            | ProjectionElem::Subtype(_)
             | ProjectionElem::OpaqueCast { .. }
             | ProjectionElem::Subslice { .. }
             | ProjectionElem::Downcast(..),
diff --git a/compiler/rustc_borrowck/src/prefixes.rs b/compiler/rustc_borrowck/src/prefixes.rs
index 6f281349863..e9c9709bd1f 100644
--- a/compiler/rustc_borrowck/src/prefixes.rs
+++ b/compiler/rustc_borrowck/src/prefixes.rs
@@ -89,6 +89,9 @@ impl<'cx, 'tcx> Iterator for Prefixes<'cx, 'tcx> {
                             cursor = cursor_base;
                             continue 'cursor;
                         }
+                        ProjectionElem::Subtype(..) => {
+                            panic!("Subtype projection is not allowed before borrow check")
+                        }
                         ProjectionElem::Deref => {
                             // (handled below)
                         }
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index d2ce6185584..1f383e5333d 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -716,6 +716,9 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
                 }
                 PlaceTy::from_ty(fty)
             }
+            ProjectionElem::Subtype(_) => {
+                bug!("ProjectionElem::Subtype shouldn't exist in borrowck")
+            }
             ProjectionElem::OpaqueCast(ty) => {
                 let ty = self.sanitize_type(place, ty);
                 let ty = self.cx.normalize(ty, location);
@@ -2563,6 +2566,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 | ProjectionElem::Subslice { .. } => {
                     // other field access
                 }
+                ProjectionElem::Subtype(_) => {
+                    bug!("ProjectionElem::Subtype shouldn't exist in borrowck")
+                }
             }
         }
     }