SOURCE_FILE
  STRUCT
    STRUCT_KW "struct"
    WHITESPACE " "
    NAME
      IDENT "S"
    WHITESPACE " "
    RECORD_FIELD_LIST
      L_CURLY "{"
      WHITESPACE "\n    "
      RECORD_FIELD
        NAME
          IDENT "a"
        COLON ":"
        WHITESPACE " "
        PATH_TYPE
          PATH
            PATH_SEGMENT
              NAME_REF
                IDENT "u32"
      WHITESPACE "\n    "
      RECORD_FIELD
        NAME
          IDENT "b"
        COLON ":"
        WHITESPACE " "
        PATH_TYPE
          PATH
            PATH_SEGMENT
              NAME_REF
                IDENT "u32"
      WHITESPACE "\n"
      R_CURLY "}"
error 21: expected COMMA