Dear forum,

this is not really a bug :

gap> if fail then Print("1\n"); else Print("2\n"); fi;
<expr> must be 'true' or 'false' (not a boolean)           # very funny :)
gap>

on ??fail, reference manual says:

But note that `fail' cannot be used to form boolean expressions with
`and', `or', and `not', and `fail' cannot appear in boolean lists (see
Chapter "Boolean Lists").

But I think, at least the message
<expr> must be 'true' or 'false' (not a boolean)
should be adjusted. Maybe so:
if IsIdenticalObj(<expr>, fail) then
Print("<expr> must be 'true' or 'false' (not 'fail')");
else
# print the usual message
fi;

PS.: I'm using GAP 4r1fix7

c ya
        Sergei

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