I’ve had to tweak my personal fork of the library for a reason I have yet to see anyone discuss here.
The standard library includes this line:
~(refuse [examine $]) %% No need for reachability.
It is, of course, true that there is no need to require reachability, but we would still like to require that the object be present, so I have replaced the line with the following:
(refuse [examine $Obj])
(just)(when $Obj is not here) %% No need for reachability.