diff --git a/jps/jps-builders-6/api-dump-unreviewed.txt b/jps/jps-builders-6/api-dump-unreviewed.txt
index 79590a30c681..f458eca86562 100644
--- a/jps/jps-builders-6/api-dump-unreviewed.txt
+++ b/jps/jps-builders-6/api-dump-unreviewed.txt
@@ -143,6 +143,7 @@ f:org.jetbrains.jps.javac.Iterators
 - s:asIterator(java.lang.Object):java.util.Iterator
 - s:collect(java.lang.Iterable,java.util.Collection):java.util.Collection
 - s:contains(java.lang.Iterable,java.lang.Object):Z
+- s:count(java.lang.Iterable):I
 - s:equals(java.lang.Iterable,java.lang.Iterable):Z
 - s:equals(java.lang.Iterable,java.lang.Iterable,org.jetbrains.jps.javac.Iterators$BiFunction):Z
 - s:filter(java.lang.Iterable,org.jetbrains.jps.javac.Iterators$BooleanFunction):java.lang.Iterable
diff --git a/jps/jps-builders-6/src/org/jetbrains/jps/javac/Iterators.java b/jps/jps-builders-6/src/org/jetbrains/jps/javac/Iterators.java
index 3643ea67e3ec..5f343366ccd8 100644
--- a/jps/jps-builders-6/src/org/jetbrains/jps/javac/Iterators.java
+++ b/jps/jps-builders-6/src/org/jetbrains/jps/javac/Iterators.java
@@ -36,6 +36,17 @@ public final class Iterators {
     return false;
   }
 
+  public static int count(Iterable<?> iterable) {
+    if (iterable instanceof Collection) {
+      return ((Collection<?>)iterable).size();
+    }
+    int count = 0;
+    for (Object obj: iterable) {
+      count += 1;
+    }
+    return count;
+  }
+
   public static <T> T find(Iterable<? extends T> iterable, BooleanFunction<? super T> cond) {
     if (iterable != null) {
       for (T o : iterable) {
diff --git a/jps/jps-builders/src/org/jetbrains/jps/dependency/java/KotlinMeta.java b/jps/jps-builders/src/org/jetbrains/jps/dependency/java/KotlinMeta.java
index 433e3c7bc888..b925321219d3 100644
--- a/jps/jps-builders/src/org/jetbrains/jps/dependency/java/KotlinMeta.java
+++ b/jps/jps-builders/src/org/jetbrains/jps/dependency/java/KotlinMeta.java
@@ -271,7 +271,7 @@ public final class KotlinMeta implements JvmMetadata<KotlinMeta, KotlinMeta.Diff
 
     @Override
     public boolean unchanged() {
-      return !becameNullable() && !argsBecameNotNull() && !receiverParameterChanged() && !visibilityChanged() && !defaultValueDeclarationChanged();
+      return !becameNullable() && !argsBecameNotNull() && !receiverParameterChanged() && !visibilityChanged() && !hasDefaultDeclarationChanges();
     }
 
     public boolean becameNullable() {
@@ -313,20 +313,13 @@ public final class KotlinMeta implements JvmMetadata<KotlinMeta, KotlinMeta.Diff
       return nowType == null || !Objects.equals(pastType.getClassifier(), nowType.getClassifier());
     }
 
-    public boolean defaultValueDeclarationChanged() {
-      Iterator<KmValueParameter> nowParams = Iterators.reverse(now.getValueParameters()).iterator();
-      for (KmValueParameter pastParam : Iterators.reverse(past.getValueParameters())) {
-        KmValueParameter nowParam = nowParams.hasNext()? nowParams.next() : null;
-        if (nowParam != null? Attributes.getDeclaresDefaultValue(nowParam) != Attributes.getDeclaresDefaultValue(pastParam) : Attributes.getDeclaresDefaultValue(pastParam)) {
-          return true;
-        }
+    public boolean hasDefaultDeclarationChanges() {
+      int before = Iterators.count(Iterators.filter(past.getValueParameters(), Attributes::getDeclaresDefaultValue));
+      int after = Iterators.count(Iterators.filter(now.getValueParameters(), Attributes::getDeclaresDefaultValue));
+      if (before == 0) {
+        return after > 0; // there were no default declarations, but some parameters now define default values
       }
-      while (nowParams.hasNext()) {
-        if (Attributes.getDeclaresDefaultValue(nowParams.next())) {
-          return true;
-        }
-      }
-      return false;
+      return after < before; // default definitions still exist, but some parameters do not define default values anymore
     }
 
     private static Iterable<KmType> getParameterTypes(KmFunction f) {
@@ -346,7 +339,7 @@ public final class KotlinMeta implements JvmMetadata<KotlinMeta, KotlinMeta.Diff
 
     @Override
     public boolean unchanged() {
-      return !argsBecameNotNull() && !visibilityChanged() && !defaultValueDeclarationChanged();
+      return !argsBecameNotNull() && !visibilityChanged() && !hasDefaultDeclarationChanges();
     }
 
     public boolean visibilityChanged() {
@@ -373,20 +366,13 @@ public final class KotlinMeta implements JvmMetadata<KotlinMeta, KotlinMeta.Diff
       return false;
     }
 
-    public boolean defaultValueDeclarationChanged() {
-      Iterator<KmValueParameter> nowParams = Iterators.reverse(now.getValueParameters()).iterator();
-      for (KmValueParameter pastParam : Iterators.reverse(past.getValueParameters())) {
-        KmValueParameter nowParam = nowParams.hasNext()? nowParams.next() : null;
-        if (nowParam != null? Attributes.getDeclaresDefaultValue(nowParam) != Attributes.getDeclaresDefaultValue(pastParam) : Attributes.getDeclaresDefaultValue(pastParam)) {
-          return true;
-        }
+    public boolean hasDefaultDeclarationChanges() {
+      int before = Iterators.count(Iterators.filter(past.getValueParameters(), Attributes::getDeclaresDefaultValue));
+      int after = Iterators.count(Iterators.filter(now.getValueParameters(), Attributes::getDeclaresDefaultValue));
+      if (before == 0) {
+        return after > 0; // there were no default declarations, but some parameters now define default values
       }
-      while (nowParams.hasNext()) {
-        if (Attributes.getDeclaresDefaultValue(nowParams.next())) {
-          return true;
-        }
-      }
-      return false;
+      return after < before; // default definitions still exist, but some parameters do not define default values anymore
     }
 
     private static Iterable<KmType> getParameterTypes(KmConstructor f) {
diff --git a/jps/jps-builders/src/org/jetbrains/jps/dependency/kotlin/KotlinAwareJavaDifferentiateStrategy.java b/jps/jps-builders/src/org/jetbrains/jps/dependency/kotlin/KotlinAwareJavaDifferentiateStrategy.java
index 962713cd6fa5..281d1f8bbd49 100644
--- a/jps/jps-builders/src/org/jetbrains/jps/dependency/kotlin/KotlinAwareJavaDifferentiateStrategy.java
+++ b/jps/jps-builders/src/org/jetbrains/jps/dependency/kotlin/KotlinAwareJavaDifferentiateStrategy.java
@@ -196,6 +196,15 @@ public final class KotlinAwareJavaDifferentiateStrategy extends JvmDifferentiate
         }
       }
 
+      for (KmFunction func : flat(metaDiff.functions().removed(), metaDiff.functions().added())) {
+        Visibility visibility = Attributes.getVisibility(func);
+        if (visibility == Visibility.PRIVATE || visibility == Visibility.PRIVATE_TO_THIS || find(func.getValueParameters(), Attributes::getDeclaresDefaultValue) == null) {
+          continue;
+        }
+        debug("Removed or added function declares default values: ", changedClass.getName());
+        affectMemberLookupUsages(context, changedClass, func.getName(), future);
+      }
+
       for (Difference.Change<KmFunction, KotlinMeta.KmFunctionsDiff> funChange : metaDiff.functions().changed()) {
         KmFunction changedKmFunction = funChange.getPast();
         Visibility visibility = Attributes.getVisibility(changedKmFunction);
@@ -221,21 +230,19 @@ public final class KotlinAwareJavaDifferentiateStrategy extends JvmDifferentiate
             affectMemberLookupUsages(context, changedClass, changedKmFunction.getName(), future);
           }
         }
-        if (funDiff.receiverParameterChanged() || funDiff.defaultValueDeclarationChanged()) {
-          debug("Function's receiver parameter changed or parameter default value declaration changed: ", changedKmFunction.getName());
+        if (funDiff.receiverParameterChanged() || funDiff.hasDefaultDeclarationChanges()) {
+          debug("Function's receiver parameter changed or function has breaking changes in default value declarations: ", changedKmFunction.getName());
           affectMemberLookupUsages(context, changedClass, changedKmFunction.getName(), future);
         }
       }
 
-      for (KmConstructor removedCons : metaDiff.constructors().removed()) {
-        Visibility visibility = Attributes.getVisibility(removedCons);
-        if (visibility == Visibility.PRIVATE || visibility == Visibility.PRIVATE_TO_THIS) {
+      for (KmConstructor con : flat(metaDiff.constructors().removed(), metaDiff.constructors().added())) {
+        Visibility visibility = Attributes.getVisibility(con);
+        if (visibility == Visibility.PRIVATE || visibility == Visibility.PRIVATE_TO_THIS || find(con.getValueParameters(), Attributes::getDeclaresDefaultValue) == null) {
           continue;
         }
-        if (find(removedCons.getValueParameters(), Attributes::getDeclaresDefaultValue) != null) {
-          debug("Removed constructor's contained default value declarations: ", changedClass.getName());
-          affectClassLookupUsages(context, changedClass);
-        }
+        debug("Removed or added constructor declares default values: ", changedClass.getName());
+        affectClassLookupUsages(context, changedClass);
       }
       
       for (Difference.Change<KmConstructor, KotlinMeta.KmConstructorsDiff> conChange : metaDiff.constructors().changed()) {
@@ -245,8 +252,8 @@ public final class KotlinAwareJavaDifferentiateStrategy extends JvmDifferentiate
           continue;
         }
         KotlinMeta.KmConstructorsDiff conDiff = conChange.getDiff();
-        if (conDiff.argsBecameNotNull() || conDiff.accessRestricted() || conDiff.defaultValueDeclarationChanged()) {
-          debug("Constructor's args became non-nullable; or the constructor has become less accessible or default value declaration changed: ", changedClass.getName());
+        if (conDiff.argsBecameNotNull() || conDiff.accessRestricted() || conDiff.hasDefaultDeclarationChanges()) {
+          debug("Constructor's args became non-nullable; or the constructor has become less accessible or has breaking changes in default value declarations: ", changedClass.getName());
           affectClassLookupUsages(context, changedClass);
         }
       }