{"ast_node_type":"variable","tokens":[{"end":37,"kind":"keyword","start":0,"text":"let"}]}
        let file_id = file_id.into();
    pub(crate) fn module_for_file_opt(&self, file_id: impl Into<FileId>) -> Option<ModuleId> {
        for &krate in self.relevant_crates(file_id).iter() {