(handler-case (compile nil '(lambda (x) (+ (reduce '+ x) x))) (warning (w) (format t "~a" w)))
Standard input is empty
Derived type of X is (VALUES SEQUENCE &OPTIONAL), conflicting with its asserted type NUMBER. See also: The SBCL Manual, Node "Handling of Types"
; in: LAMBDA (X) ; (+ (REDUCE '+ X) X) ; ; note: deleting unreachable code ; ; compilation unit finished ; caught 1 fatal ERROR condition ; printed 1 note