(negation-type-type x))
(!define-type-method (negation :unparse) (x)
- `(not ,(type-specifier (negation-type-type x))))
+ (if (type= (negation-type-type x) (specifier-type 'cons))
+ 'atom
+ `(not ,(type-specifier (negation-type-type x)))))
(!define-type-method (negation :simple-subtypep) (type1 type2)
(csubtypep (negation-type-type type2) (negation-type-type type1)))