remove setof/3, bagof/3 non-determinism (#270)

src/prolog/lib/builtins.pl

@@ -456,7 +456,10 @@ group_by_variants([V-S|Pairs], [V-Solution|Solutions]) :-
     group_by_variants(Pairs0, Solutions).
 group_by_variants([], []).
 
-iterate_variants([V-Solution|GroupSolutions], V, Solution).
+iterate_variants([V-Solution|GroupSolutions], V, Solution) :-
+    (  GroupSolutions == [] -> !
+    ;  true
+    ).
 iterate_variants([_|GroupSolutions], Ws, Solution) :-
     iterate_variants(GroupSolutions, Ws, Solution).
 
@@ -491,7 +494,10 @@ bagof(Template, Goal, Solution) :-
     iterate_variants(GroupedSolutions, Witnesses, Solution).
 
 iterate_variants_and_sort([V-Solution0|GroupSolutions], V, Solution) :-
-    sort(Solution0, Solution).
+    sort(Solution0, Solution),
+    (  GroupSolutions == [] -> !
+    ;  true
+    ).
 iterate_variants_and_sort([_|GroupSolutions], Ws, Solution) :-
     iterate_variants_and_sort(GroupSolutions, Ws, Solution).
 

src/prolog/machine/machine_state_impl.rs

@@ -3169,7 +3169,8 @@ impl MachineState {
         false
     }
 
-    pub(super) fn setup_built_in_call(&mut self, ct: BuiltInClauseType) {
+    pub(super)
+    fn setup_built_in_call(&mut self, ct: BuiltInClauseType) {
         self.num_of_args = ct.arity();
         self.b0 = self.b;