Print_term doesn't like compound with zero arity

General
1 
$ swipl --no-tty
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1 ?- print_term(foo, []).
foo
true.

2 ?- print_term(foo(), []).
ERROR: Domain error: `compound_non_zero_arity' expected, found `foo()'
ERROR: In:
ERROR:   [11] functor(foo(),_3352,_3354)
ERROR:   [10] prolog_pretty_print:pp(foo(),ctx(0,0,1200,infinite),[output(user_output),...|...]) at /usr/lib/swi-prolog/library/pprint.pl:300
ERROR:    [9] prolog_pretty_print:print_term_2(foo(),[]) at /usr/lib/swi-prolog/library/pprint.pl:118
ERROR:    [8] prolog_pretty_print:print_term(foo(),[]) at /usr/lib/swi-prolog/library/pprint.pl:108
ERROR:    [7] <user>
   Exception: (10) prolog_pretty_print:pp(foo(), ctx(0, 0, 1200, infinite), [output(user_output), right_margin(72), indent_arguments(auto), operators(true), write_options([quoted(...)|...])]) ? w
   Exception: (10) prolog_pretty_print:pp(foo(), ctx(0, 0, 1200, infinite), [output(user_output), right_margin(72), indent_arguments(auto), operators(true), write_options([quoted(true), numbervars(true), portray(true), attributes(portray)])]) ? a
% Execution Aborted
2

Thanks. Fixed with cb97020bf84b56c8864a7b9c1b4009c1a31a2511