{"ast_node_type":"other","tokens":[{"end":83,"kind":"keyword","start":0,"text":"(Err(err),"}]}
            (Err(err), Some((start_span, left))) if self.eat_keyword(exp!(In)) => {
            (Ok(pat), _) => pat, // Happy path.
                // We know for sure we have seen `for ($SOMETHING in`. In the happy path this would