+;;; Bug 84: SB-KERNEL:CSUBTYPEP was a bit enthusiastic at
+;;; special-casing calls to subtypep involving *EMPTY-TYPE*,
+;;; corresponding to the NIL type-specifier; we were bogusly returning
+;;; NIL, T (indicating surety) for the following:
+(assert-nil-nil (subtypep '(satisfies some-undefined-fun) 'nil))