Broken on ACL

[Gleefre]

Seems to be broken on Allegro CL:

Error: Class
       #<COMMON-LISP:STANDARD-CLASS SEALABLE-METAOBJECT-INSTANCE @
         #x10007a60e72>'s
       metaclass is not compatible with its designated superclass
       #<BUILT-IN-CLASS T>
  [condition type: PROGRAM-ERROR]

In particular, it seems that inheriting from T doesn't work:

CL-USER> (defclass foo (t) ())
Error: Class #<STANDARD-CLASS FOO @ #x10007a6cba2>'s metaclass is not
       compatible with its designated superclass #<BUILT-IN-CLASS T>
  [condition type: PROGRAM-ERROR]

Restart actions (select using :continue):
 0: Return to Top Level (an "abort" restart).
 1: Abort entirely from this (lisp) process.