SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "f"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE " "
        EXPR_STMT
          BLOCK_EXPR
            LABEL
              LIFETIME
                LIFETIME_IDENT "'label"
              COLON ":"
            WHITESPACE " "
            STMT_LIST
              L_CURLY "{"
              R_CURLY "}"
          SEMICOLON ";"
        WHITESPACE " "
        R_CURLY "}"
  WHITESPACE "\n"