Basic fixing function for literals.
Function:
(defun lit-fix$inline (x) (declare (xargs :guard (litp x))) (let ((__function__ 'lit-fix)) (declare (ignorable __function__)) (lnfix x)))
Theorem:
(defthm litp-of-lit-fix (b* ((x-fix (lit-fix$inline x))) (litp x-fix)) :rule-classes :type-prescription)
Theorem:
(defthm lit-fix-of-lit (implies (litp x) (equal (lit-fix x) x)))