The value :UNKNOWN is not of type REAL

[Paul F. Dietz]

(lambda ()
  (catch 'ct4
    (flet ((%f (x y) x))
      (apply
       #'%f
       (apply #'%f (list 0 (apply (constantly 0) 0 0 nil)))
       (dotimes (iv4 0 0))
       nil))))

==>

The value
  :UNKNOWN
is not of type
  REAL
   [Condition of type TYPE-ERROR]
[...]
Backtrace:
  0: (SB-C::LTN-ANALYZE-MV-BIND #<SB-C::MV-COMBINATION :FUN #<SB-C::REF :LEAF #<SB-C::CLAMBDA :%SOURCE-NAME SB-C::.ANONYMOUS. :%DEBUG-NAME # :KIND :MV-LET :TYPE #<SB-KERNEL:BUILT-IN-CLASSOID FUNCTION (rea..
  1: (SB-C::LTN-ANALYZE-BLOCK #<SB-C::CBLOCK 8 :START c1 {100B676683}>)
  2: (SB-C::LTN-ANALYZE #<SB-C:COMPONENT :NAME "<unknown>" {100B68B063}>)
  3: (SB-C::%COMPILE-COMPONENT #<SB-C:COMPONENT :NAME "<unknown>" {100B68B063}>)
[...]

x86-64, "2.3.0.84-10d2e8903"