The swank ECL backend discards the first argument in arglists obtained via grovel-docstring-for-arglist due to a CDR applied to the return value. This behavior dates back to the original version of the function in revision 1.32 and I can't figure a good reason for it (unless ECL is inconsistent in its documentation format). I first encountered this behavior upon observing that slime's arglist for POSITION-IF omitted the test argument. Attached is the trivial fix.