Section 13-1.2. Assets; debt due from executor to testator; effect of discharge

by will
    The  designation by will of a person as executor does not operate as a
  discharge or testamentary  disposition  of  any  just  claim  which  the
  testator had against him, but such claim must be included as an asset of
  the  estate.   The executor is liable for the value of the claim when it
  becomes due, and he must apply and distribute the same in the course  of
  administering  the estate.  The discharge or disposition of such a claim
  or of a claim against any other person by will shall  be  treated  as  a
  specific  disposition  for purposes of 13-1.3.  Nothing contained herein
  precludes an executor from raising any defense to a claim by the  estate
  against  him  which  would be available to any other person against whom
  the estate has a claim.