- DOCUMENT@0..22
    - UNION_TYPE_DEFINITION@0..22
        - union_KW@0..5 "union"
        - WHITESPACE@5..6 " "
        - UNION_MEMBER_TYPES@6..22
            - EQ@6..7 "="
            - WHITESPACE@7..8 " "
            - NAMED_TYPE@8..13
                - NAME@8..13
                    - IDENT@8..13 "Photo"
            - WHITESPACE@13..14 " "
            - PIPE@14..15 "|"
            - WHITESPACE@15..16 " "
            - NAMED_TYPE@16..22
                - NAME@16..22
                    - IDENT@16..22 "Person"
- ERROR@6:7 "expected a Name" =
recursion limit: 500, high: 0