Begin to implement type system layer of unsafe binders

compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs

@@ -83,7 +83,8 @@ pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
         | ty::Placeholder(..)
         | ty::Infer(_)
         | ty::Bound(..)
-        | ty::Coroutine(..) => false,
+        | ty::Coroutine(..)
+        | ty::UnsafeBinder(_) => false,
     }
 }
 
@@ -336,6 +337,11 @@ pub fn dtorck_constraint_for_ty_inner<'tcx>(
             constraints.dtorck_types.push(ty);
         }
 
+        // Can't instantiate binder here.
+        ty::UnsafeBinder(_) => {
+            constraints.dtorck_types.push(ty);
+        }
+
         ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error(_) => {
             // By the time this code runs, all type variables ought to
             // be fully resolved.