A routine with no precondition (i.e., an implicit precondition of
`true') is redefined in a descendant with alternative precondition
`false'.  The full precondition of the redefined routine is therefore
`true or else false'.  But when the system is compiled with `assertion
(require)' and executed, the redefined routine's precondition is
violated.

Discovered in Prerelease 93.07.15.