{"ast_node_type":"variable","tokens":[{"end":97,"kind":"keyword","start":0,"text":"if"}]}
        if let Some(&existing) = self.untracked().stable_crate_ids.read().get(&stable_crate_id) {
    ) -> Result<TyCtxtFeed<'tcx, CrateNum>, CrateNum> {
            return Err(existing);