{"ast_node_type":"function","tokens":[{"end":94,"kind":"keyword","start":0,"text":"fn"}]}
    fn child_by_source_to(&self, db: &dyn DefDatabase, res: &mut DynMap, file_id: HirFileId) {
impl ChildBySource for GenericDefId {
        let (gfile_id, generic_params_list) = self.file_id_and_params_of(db);