To help out with the cleaning up of the backtrace:
Welcome to SWI-Prolog (threaded, 64 bits, version 8.1.10) SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software. Please run ?- license. for legal details. For online help and background, visit http://www.swi-prolog.org For built-in help, use ?- help(Topic). or ?- apropos(Word). 1 ?- a() =.. [F|A]. ERROR: Domain error: `compound_non_zero_arity' expected, found `a()' ERROR: In: ERROR:  a()=..[_6754|_6756] ERROR:  '$tabling':'$wfs_call'(user:(... =.. ...),user:_6806) at /usr/lib/swipl/boot /tabling.pl:680 2 ?-
I think the
$wfs_call should not show up.