+ ;; Note we intentionally call %DEFSTRUCT first, and
+ ;; especially before %COMPILER-DEFSTRUCT. %DEFSTRUCT
+ ;; has the tests (and resulting CERROR) for collisions
+ ;; with LAYOUTs which already exist in the runtime. If
+ ;; there are any collisions, we want the user's
+ ;; response to CERROR to control what happens.
+ ;; Especially, if the user responds to the collision
+ ;; with ABORT, we don't want %COMPILER-DEFSTRUCT to
+ ;; modify the definition of the class.
+ (%defstruct ',dd ',inherits)