es-0.90-alpha dumping core on a ~~

[Soren Dayton <csdayton@midway.uchicago.edu>]

woodlawn:~:
; echo <={ variable = <={ %split / $wd } }
nfs woodlawn w4 csdayton

woodlawn:~:
; echo <={ variable = $variable( 3 ... ) }
w4 csdayton

woodlawn:~:
; echo <={ ~~ $variable(1) [qwek][0-9] }
match.c:206: assertion failed (j != RANGE_FAIL)

Process shell abort (core dumped)

After a quick glance at the code, I do not see what the problem is...
Is there a list of known bugs and patches somewhere?  I would really
like to use the alpha for reasons like ~~.

Thanks
Soren