+;;; bug 12: type system didn't grok nontrivial intersections
+(assert (subtypep '(and symbol (satisfies keywordp)) 'symbol))
+(assert (not (subtypep '(and symbol (satisfies keywordp)) 'null)))
+(assert (subtypep 'keyword 'symbol))
+(assert (not (subtypep 'symbol 'keyword)))
+(assert (subtypep 'ratio 'real))
+(assert (subtypep 'ratio 'number))
+