(defun testcover-reinstrument (form)
"Reinstruments FORM to use testcover instead of edebug. This
function modifies the list that FORM points to. Result is nil if
-FORM should return multiple vlues, t if should always return same
+FORM should return multiple values, t if should always return same
value, 'maybe if either is acceptable."
(let ((fun (car-safe form))
id val)