SOURCE_FILE
  ATTR
    POUND "#"
    BANG "!"
    L_BRACK "["
    CFG_META
      CFG_KW "cfg"
      L_PAREN "("
      CFG_ATOM
        IDENT "key"
        WHITESPACE " "
        EQ "="
        WHITESPACE " "
        ERROR
          IDENT "value"
      R_PAREN ")"
    R_BRACK "]"
  WHITESPACE "\n"
error 13: expected a string literal
