;;; then we also check whether the layout for the object is invalid
;;; and signal an error if so. Otherwise, look up the indirect
;;; class-cell and call CLASS-CELL-TYPEP at runtime.
;;; then we also check whether the layout for the object is invalid
;;; and signal an error if so. Otherwise, look up the indirect
;;; class-cell and call CLASS-CELL-TYPEP at runtime.