third argument of copy_term should be instantiated as a list (#1747)

2023-02-26 16:29:39 -07:00
parent 24eb9ce483
commit 3286e78cd2
1 changed files with 5 additions and 1 deletions
--- a/src/machine/project_attributes.pl
+++ b/src/machine/project_attributes.pl
@@ -111,7 +111,11 @@ delete_all_attributes_from_var(V) :- '$delete_all_attributes_from_var'(V).

 copy_term(Term, Copy, Gs) :-
   can_be(list, Gs),
-   findall(Term-Rs, term_residual_goals(Term,Rs), [Copy-Gs]).
+   findall(Term-Rs, term_residual_goals(Term,Rs), [Copy-Gs]),
+   (  var(Gs) ->
+      Gs = []
+   ;  true
+   ).

 term_residual_goals(Term,Rs) :-
    '$term_attributed_variables'(Term, Vs),