I don't have a clue how I managed to get that result. I am trying to simplify and reproduce. Anyone has an idea on how this could happen?
zz is set! in a lambda called by a macro in cotypes.
Gambit Version 4.0 beta 17
(aa)
"c:/dev/aaScratch/com/costruct.scm"
(define zz 0) (aac "cotypes")
#t
zz
'(ctype: "short" type*: VT_PTR ctype*: "void*" ctype+: #f)
(memq type*: zz)
#f
(define xx '(ctype: "short" type*: VT_PTR ctype*: "void*" ctype+: #f)) (memq type*: xx)
(type*: VT_PTR ctype*: "void*" ctype+: #f)