(in-package :ccl)

;; optimizers.lisp:
(let ((ccl:*warn-if-redefine-kernel* nil))
  (define-compiler-macro aref (&whole call a &rest subscripts &environment env)
    (let* ((ctype (if (nx-form-typep a 'array env)
                    (specifier-type (nx-form-type a env) env)))
           (ectype (typecase ctype
                     (array-ctype (array-ctype-specialized-element-type ctype))
                     (union-ctype (when (every #'array-ctype-p (union-ctype-types ctype))
                                    (%type-union
                                     (mapcar (lambda (ct) (array-ctype-specialized-element-type ct))
                                             (union-ctype-types ctype)))))))
           (etype (and ectype (type-specifier ectype)))
           (useful (unless (or (eq etype '*) (eq etype t)) ;<---
                     etype)))
      (if (= 2 (length subscripts))
        (setq call `(%aref2 ,a ,@subscripts))
        (if (= 3 (length subscripts))
          (setq call `(%aref3 ,a ,@subscripts))))
      (if useful
        `(the ,useful ,call)
        call))))