(defun %defun (name def &optional inline-lambda extra-info)
  (declare (type function def))
  ;; should've been checked by DEFMACRO DEFUN
  (aver (legal-fun-name-p name))
  ;; If a warning handler decides to disallow this redefinition
  ;; by nonlocally exiting, then we'll skip the rest of this stuff.
  (when (and (fboundp name)
             *type-system-initialized*)
    (handler-bind (((satisfies sb-c::handle-condition-p)
                     #'sb-c::handle-condition-handler))
      (warn 'redefinition-with-defun :name name :new-function def)))
  (sb-c:%compiler-defun name nil inline-lambda extra-info)
  (setf (fdefinition name) def)