Driveby fixes

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

@@ -350,6 +350,8 @@ pub fn dtorck_constraint_for_ty_inner<'tcx>(
             // Note that we don't care about whether the resume type has any drops since this is
             // redundant; there is no storage for the resume type, so if it is actually stored
             // in the interior, we'll already detect the need for a drop by checking the interior.
+            //
+            // FIXME(@lcnr): Why do we erase regions in the env here? Seems odd
             let typing_env = tcx.erase_and_anonymize_regions(typing_env);
             let needs_drop = tcx.mir_coroutine_witnesses(def_id).is_some_and(|witness| {
                 witness.field_tys.iter().any(|field| field.ty.needs_drop(tcx, typing_env))