{"ast_node_type":"other","tokens":[{"end":55,"kind":"keyword","start":0,"text":"self.eat_to_tokens(&[exp!(OpenBrace)]);"}]}
                self.eat_to_tokens(&[exp!(OpenBrace)]);
            let err = if self.check(exp!(RArrow)) || self.check(exp!(OpenBrace)) {
                self.bump(); // `{`