srfi-130-test.scm has this code

(or (eqv? #f
          (string-cursor->index "abcdeffffoo"
                                (string-contains "abcdeffffoo" "efffoo")))
    (fail 'string-contains))

where string-contains returns #f. My interpretation of the srfi is
string-cursor->index only lets indexes through besides cursors, so if
it works in this case (by design) then #f has to be a valid index?

The alternative is of course simpler, the test is wrong (because the
reference implementation lets anything through) and
string-cursor->index should not be called here. I tried it out on
chibi, string->cursor->index there does not accept #f either.
--
Duy