RETURN ERROR should have a string argument

Rule "errortext" gives this warning when it finds a "RETURN ERROR" statement without a string argument. For example:

/* prolint raises a warning: */
IF NOT AVAILABLE customer THEN 
   RETURN ERROR.
/* this is fine with prolint: */
IF NOT AVAILABLE customer THEN 
   RETURN ERROR "no data available".

How to suppress these warnings:

You can put the directive {&_proparse_ prolint-nowarn(errortext)} directly before
the RETURN ERROR statement. See also: suppress warnings.