- DOCUMENT@0..61
    - ERROR@0..6 "extend"
    - WHITESPACE@6..7 " "
    - ERROR@7..10 "Cat"
    - WHITESPACE@10..12 "\n\n"
    - INTERFACE_TYPE_EXTENSION@12..61
        - extend_KW@12..18 "extend"
        - WHITESPACE@18..19 " "
        - interface_KW@19..28 "interface"
        - WHITESPACE@28..29 " "
        - NAME@29..40
            - IDENT@29..40 "NamedEntity"
        - WHITESPACE@40..41 " "
        - FIELDS_DEFINITION@41..61
            - L_CURLY@41..42 "{"
            - WHITESPACE@42..47 "\n    "
            - FIELD_DEFINITION@47..59
                - NAME@47..51
                    - IDENT@47..51 "name"
                - COLON@51..52 ":"
                - WHITESPACE@52..53 " "
                - NAMED_TYPE@53..59
                    - NAME@53..59
                        - IDENT@53..59 "String"
            - WHITESPACE@59..60 "\n"
            - R_CURLY@60..61 "}"
- ERROR@0:6 "Invalid Type System Extension. This extension cannot be applied." extend
- ERROR@7:10 "expected definition" Cat
recursion limit: 4096, high: 0