Redefining structure accessors (summary)

Let's see if I can summarize the discussion. Attempts to redefine structure accessors should be a cerror. If you continue, then the structure is undefined (mostly) and the function is created. This seems better than the current behavior of just warning you about it and undefining the structure anyway. (compile accessor new-def) should also be a cerror. (setf (fdefinition accessor) new-def) shouldn't do anything special. The structure printer and inspector should be modified to use %instance-ref so that we can still print and inspect structures even if the accessor has been redefined. How does that sound? Ray