fix was made to ROUND-NUMERIC-BOUND for the sbcl-0.9.6 release, but
the right fix is to remove the abstraction violation in the
compiler's type deriver.
+
+390:
+ reported on sbcl-help by Tim Daly Jr.
+
+ (DIRECTORY "/tmp/[P]*.*")
+ gives a type error:
+ The value "P" is not of type CHARACTER.