This is an ordinary defenum.
Function:
(defun interp-st-field-p (x) (declare (xargs :guard t)) (or (eq x ':stack) (eq x ':logicman) (eq x ':bvar-db) (eq x ':pathcond) (eq x ':constraint) (eq x ':constraint-db) (eq x ':prof) (eq x ':backchain-limit) (eq x ':equiv-contexts) (eq x ':reclimit) (eq x ':config) (eq x ':flags) (eq x ':fgarrays) (eq x ':next-fgarray) (eq x ':cgraph) (eq x ':cgraph-memo) (eq x ':cgraph-index) (eq x ':ctrex-env) (eq x ':sat-ctrex) (eq x ':user-scratch) (eq x ':trace-scratch) (eq x ':errmsg) (eq x ':debug-info) (eq x ':debug-stack)))
Theorem: type-when-interp-st-field-p
(defthm type-when-interp-st-field-p (implies (interp-st-field-p x) (if (symbolp x) (if (not (equal x 't)) (not (equal x 'nil)) 'nil) 'nil)) :rule-classes :compound-recognizer)