VMS Help CC, Messages, EXPRNOTUSED  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        <Context> the expression "<expr>" is never used.

 Description    The compiler has detected an expression that is not
                used, and might not have a side-effect.  This might
                not have been what you intended.

 User Action    If the expression has a desired side-effect, the
                message can be ignored.  Otherwise, you might want to
                consider removing the expression.