Quoting Sean Champ (gimmal@gmail.com):
; (MAP-INTO CXML::RESULT #'RUNES:CODE-RUNE CXML::BUFFER) ; --> DO BLOCK LET TAGBODY RETURN-FROM PROGN WHEN COND IF PROGN SETF ; ==> ; (SB-KERNEL:%SET-FILL-POINTER SB-C::RESULT SB-INT:INDEX) ; ; caught WARNING: ; Asserted type ARRAY conflicts with derived type ; (VALUES (SIMPLE-ARRAY CHARACTER (*)) &OPTIONAL).
I am told this is (was) a bug in SBCL's instrumentation-based stepping code (enabled by the high DEBUG setting you seem to be using) which has already been fixed in SBCL CVS.
d.