fixed Winter's Rest throwing an error

Mage.Sets/src/mage/cards/w/WintersRest.java

@@ -3,8 +3,6 @@ package mage.cards.w;
 import mage.abilities.Ability;
 import mage.abilities.common.EntersBattlefieldTriggeredAbility;
 import mage.abilities.common.SimpleStaticAbility;
-import mage.abilities.condition.common.PermanentsOnTheBattlefieldCondition;
-import mage.abilities.decorator.ConditionalContinuousEffect;
 import mage.abilities.effects.common.AttachEffect;
 import mage.abilities.effects.common.DontUntapInControllersUntapStepEnchantedEffect;
 import mage.abilities.effects.common.TapEnchantedEffect;
@@ -19,6 +17,8 @@ import mage.filter.FilterPermanent;
 import mage.filter.common.FilterControlledPermanent;
 import mage.filter.predicate.mageobject.SupertypePredicate;
 import mage.filter.predicate.permanent.AnotherPredicate;
+import mage.game.Game;
+import mage.game.events.GameEvent;
 import mage.target.TargetPermanent;
 import mage.target.common.TargetCreaturePermanent;
 
@@ -29,13 +29,6 @@ import java.util.UUID;
  */
 public final class WintersRest extends CardImpl {
 
-    private static final FilterPermanent filter = new FilterControlledPermanent();
-
-    static {
-        filter.add(AnotherPredicate.instance);
-        filter.add(new SupertypePredicate(SuperType.SNOW));
-    }
-
     public WintersRest(UUID ownerId, CardSetInfo setInfo) {
         super(ownerId, setInfo, new CardType[]{CardType.ENCHANTMENT}, "{1}{U}");
 
@@ -53,12 +46,7 @@ public final class WintersRest extends CardImpl {
         this.addAbility(new EntersBattlefieldTriggeredAbility(new TapEnchantedEffect()));
 
         // As long as you control another snow permanent, enchanted creature doesn't untap during its controller's untap step.
-        this.addAbility(new SimpleStaticAbility(new ConditionalContinuousEffect(
+        this.addAbility(new SimpleStaticAbility(new WintersRestEffect()));
-                new DontUntapInControllersUntapStepEnchantedEffect(),
-                new PermanentsOnTheBattlefieldCondition(filter),
-                "As long as you control another snow permanent, " +
-                        "enchanted creature doesn't untap during its controller's untap step."
-        )));
     }
 
     private WintersRest(final WintersRest card) {
@@ -70,3 +58,38 @@ public final class WintersRest extends CardImpl {
         return new WintersRest(this);
     }
 }
+
+class WintersRestEffect extends DontUntapInControllersUntapStepEnchantedEffect {
+
+    private static final FilterPermanent filter = new FilterControlledPermanent();
+
+    static {
+        filter.add(AnotherPredicate.instance);
+        filter.add(new SupertypePredicate(SuperType.SNOW));
+    }
+
+    WintersRestEffect() {
+        super();
+        staticText = "As long as you control another snow permanent, " +
+                "enchanted creature doesn't untap during its controller's untap step.";
+    }
+
+    private WintersRestEffect(final WintersRestEffect effect) {
+        super(effect);
+    }
+
+    @Override
+    public WintersRestEffect copy() {
+        return new WintersRestEffect(this);
+    }
+
+    @Override
+    public boolean applies(GameEvent event, Ability source, Game game) {
+        if (game.getBattlefield().getActivePermanents(
+                filter, source.getControllerId(), source.getSourceId(), game
+        ).isEmpty()) {
+            return false;
+        }
+        return super.applies(event, source, game);
+    }
+}