Very minor: In testing the implementation, I needed to edit
srfi/146/hash.sld to import (gleckler hamt-map) the import of
(hamt-map).  (Trivial diff below.)

With that change, I am glad to report that I was able to do a simple

  chibi-scheme -A . tests.scm

to run the tests. (In earlier versions I needed to add some more
options, symlinks, etc.)  A few tests were skipped and I haven't looked
at those closely yet but I suspect that behavior is expected.  Some more

​ ​

details below.