diff --git a/Mage.Sets/src/mage/cards/c/Conversion.java b/Mage.Sets/src/mage/cards/c/Conversion.java
index 34b8a20880..3204856e19 100644
--- a/Mage.Sets/src/mage/cards/c/Conversion.java
+++ b/Mage.Sets/src/mage/cards/c/Conversion.java
@@ -33,6 +33,7 @@ import mage.abilities.common.SimpleStaticAbility;
 import mage.abilities.costs.mana.ManaCostsImpl;
 import mage.abilities.effects.ContinuousEffect;
 import mage.abilities.effects.ContinuousEffectImpl;
+import mage.abilities.effects.Effect;
 import mage.abilities.effects.common.SacrificeSourceUnlessPaysEffect;
 import mage.abilities.mana.WhiteManaAbility;
 import mage.cards.CardImpl;
@@ -46,6 +47,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.UUID;
+import java.util.stream.Collectors;
 
 /**
  *
@@ -121,17 +123,11 @@ public class Conversion extends CardImpl {
         @Override
         public Set<UUID> isDependentTo(List<ContinuousEffect> allEffectsInLayer) {
             // the dependent classes needs to be an enclosed class for dependent check of continuous effects
-            Set<UUID> dependentTo = null;
-            for (ContinuousEffect effect : allEffectsInLayer) {
-                // http://www.mtgsalvation.com/forums/magic-fundamentals/magic-rulings/magic-rulings-archives/286046-conversion-magus-of-the-moon
-                if (effect.getDependencyTypes().contains(DependencyType.BecomeMountain)) {
-                    if (dependentTo == null) {
-                        dependentTo = new HashSet<>();
-                    }
-                    dependentTo.add(effect.getId());
-                }
-            }
-            return dependentTo;
+            return allEffectsInLayer.stream()
+                    .filter(effect->effect.getDependencyTypes().contains(DependencyType.BecomeMountain))
+                    .map(Effect::getId)
+                    .collect(Collectors.toSet());
+
         }
 
     }
diff --git a/Mage.Sets/src/mage/cards/o/Opalescence.java b/Mage.Sets/src/mage/cards/o/Opalescence.java
index 28807d38ba..20c65786b1 100644
--- a/Mage.Sets/src/mage/cards/o/Opalescence.java
+++ b/Mage.Sets/src/mage/cards/o/Opalescence.java
@@ -138,13 +138,10 @@ class OpalescenceEffect extends ContinuousEffectImpl {
 
     @Override
     public Set<UUID> isDependentTo(List<ContinuousEffect> allEffectsInLayer) {
-        Set<UUID> dependentTo = null;
+        Set<UUID> dependentTo = new HashSet<>();
         for (ContinuousEffect effect : allEffectsInLayer) {
             for (DependencyType dependencyType : effect.getDependencyTypes()) {
                 if (checkDependencyTypes.contains(dependencyType)) {
-                    if (dependentTo == null) {
-                        dependentTo = new HashSet<>();
-                    }
                     dependentTo.add(effect.getId());
                 }
             }
diff --git a/Mage.Sets/src/mage/cards/s/StarfieldOfNyx.java b/Mage.Sets/src/mage/cards/s/StarfieldOfNyx.java
index 75d9ffb756..c1fedb67e5 100644
--- a/Mage.Sets/src/mage/cards/s/StarfieldOfNyx.java
+++ b/Mage.Sets/src/mage/cards/s/StarfieldOfNyx.java
@@ -31,6 +31,8 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.UUID;
+import java.util.stream.Collectors;
+
 import mage.abilities.Ability;
 import mage.abilities.common.BeginningOfUpkeepTriggeredAbility;
 import mage.abilities.common.SimpleStaticAbility;
@@ -38,6 +40,7 @@ import mage.abilities.condition.common.PermanentsOnTheBattlefieldCondition;
 import mage.abilities.decorator.ConditionalContinuousEffect;
 import mage.abilities.effects.ContinuousEffect;
 import mage.abilities.effects.ContinuousEffectImpl;
+import mage.abilities.effects.Effect;
 import mage.abilities.effects.common.ReturnFromGraveyardToBattlefieldTargetEffect;
 import mage.cards.CardImpl;
 import mage.cards.CardSetInfo;
@@ -166,16 +169,7 @@ class StarfieldOfNyxEffect extends ContinuousEffectImpl {
 
     @Override
     public Set<UUID> isDependentTo(List<ContinuousEffect> allEffectsInLayer) {
-        Set<UUID> dependentTo = null;
-        for (ContinuousEffect effect : allEffectsInLayer) {
-            // http://www.slightlymagic.net/forum/viewtopic.php?f=70&t=17664&start=30#p185513
-            if (effect.getDependencyTypes().contains(DependencyType.AuraAddingRemoving)) {
-                if (dependentTo == null) {
-                    dependentTo = new HashSet<>();
-                }
-                dependentTo.add(effect.getId());
-            }
-        }
-        return dependentTo;
+        return allEffectsInLayer.stream().filter(effect->effect.getDependencyTypes().contains(DependencyType.AuraAddingRemoving)).map(Effect::getId).collect(Collectors.toSet());
+
     }
 }