Begin to implement type system layer of unsafe binders

compiler/rustc_ty_utils/src/instance.rs

@@ -49,7 +49,8 @@ fn resolve_instance_raw<'tcx>(
                     | ty::Adt(..)
                     | ty::Dynamic(..)
                     | ty::Array(..)
-                    | ty::Slice(..) => {}
+                    | ty::Slice(..)
+                    | ty::UnsafeBinder(..) => {}
                     // Drop shims can only be built from ADTs.
                     _ => return Ok(None),
                 }

compiler/rustc_ty_utils/src/layout.rs

@@ -666,6 +666,11 @@ fn layout_of_uncached<'tcx>(
             tcx.mk_layout(layout)
         }
 
+        ty::UnsafeBinder(bound_ty) => {
+            let ty = tcx.instantiate_bound_regions_with_erased(bound_ty.into());
+            cx.layout_of(ty)?.layout
+        }
+
         // Types with no meaningful known layout.
         ty::Alias(..) => {
             // NOTE(eddyb) `layout_of` query should've normalized these away,

compiler/rustc_ty_utils/src/needs_drop.rs

@@ -202,6 +202,11 @@ where
                         }
                     }
 
+                    ty::UnsafeBinder(bound_ty) => {
+                        let ty = self.tcx.instantiate_bound_regions_with_erased(bound_ty.into());
+                        queue_type(self, ty);
+                    }
+
                     _ if tcx.type_is_copy_modulo_regions(self.typing_env, component) => {}
 
                     ty::Closure(_, args) => {

compiler/rustc_ty_utils/src/ty.rs

@@ -37,6 +37,8 @@ fn sized_constraint_for_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'
         | Never
         | Dynamic(_, _, ty::DynStar) => None,
 
+        UnsafeBinder(_) => todo!(),
+
         // these are never sized
         Str | Slice(..) | Dynamic(_, _, ty::Dyn) | Foreign(..) => Some(ty),