Unsafe variable error

[nrueh]

I get the following error

INFO:waitress:Serving on http://127.0.0.1:5050
<block>:37:1-273: error: unsafe variables in:
  h(20,"8b3ea9ef14a7448366742cf1285f325d476bbdff",satisfied(C,ID),(column(C,ID,ANON_154_155_,ANON_156_157_),allow(Idx,(#Anon0,Row),ANON_138_139_))):-[#inc_base];column(C,ID,ANON_154_155_,ANON_156_157_);#p_allow(#b(Idx),(#p,#b(Row)),#b(ANON_138_139_));satisfied(C,ID);(Idx,#Anon1)=C;not not_hit(C,ID,Row);C=(Idx,#Anon1).
<block>:37:118-119: note: '#Anon0' is unsafe

which I believe stems from this (safe) rule

satisfied(C,ID) :- allow(Idx,(_,Row),_), column(C,ID,_,_), C=(Idx,_), not not_hit(C,ID,Row).
``

[stephanzwicknagl]

This happens due to the Anon variable in the nested Tuple of the rule. As a temporary workaround, you can name them, e.g.

satisfied(C,ID) :- allow(Idx,(TEMPANON,Row),_), column(C,ID,_,_), C=(Idx,_), not not_hit(C,ID,Row).