;;; Array access functions return an object from the array, hence its type is
;;; going to be the array upgraded element type. Secondary return value is the
;;; known supertype of the upgraded-array-element-type, if if the exact
;;; Array access functions return an object from the array, hence its type is
;;; going to be the array upgraded element type. Secondary return value is the
;;; known supertype of the upgraded-array-element-type, if if the exact