bug#30494: 25.2; (setting-constant nil) error in sql.el

[sciamano@yandex.ru]

Hi,

i'm trying to add SQL product by following steps from the introduction
section in the sql.el, but for the settings
:sqli-program
:sqli-login
:sqli-options
it fails with "attemt to set a constant symbol: nil"

In 'emacs -Q' executing it step-by-step:

(require 'sql)

(sql-add-product 'xyz "XyzDB"
                 '(:free-software t))

(defcustom my-sql-xyz-program "ixyz"
  "Command to start ixyz by XyzDB."
  :type 'file
  :group 'SQL)

;; NEXT STEP FAILS WITH:
;; Debugger entered--Lisp error: (setting-constant nil)
;;  sql-set-product-feature(xyz :sqli-program my-sql-xyz-program)
;;  eval((sql-set-product-feature (quote xyz) :sqli-program (quote my-sql-xyz-program)) nil)
(sql-set-product-feature 'xyz
                         :sqli-program 'my-sql-xyz-program)

;; BUT THIS TWO ARE OK
(sql-set-product-feature 'xyz
			 :prompt-regexp "^xyzdb> ")
(sql-set-product-feature 'xyz
			 :prompt-length 7)


-- 
Denis