Merge pull request #3189 from Skgland/fix-function_casts_as_integer

fix `function_casts_as_integer` warning

src/machine/machine_state_impl.rs

@@ -61,8 +61,7 @@ impl MachineState {
             cc: 0,
             global_clock: 0,
             dynamic_mode: FirstOrNext::First,
-            unify_fn: MachineState::unify,
-            bind_fn: MachineState::bind,
+            occurs_check: &Nsto,
             run_cleaners_fn: |_| false,
             throwing_resource_error: false,
         }
@@ -624,7 +623,7 @@ impl MachineState {
             }
         };
 
-        (self.bind_fn)(self, r, f_a);
+        self.occurs_check.bind(self, r, f_a);
         Ok(())
     }