equals.diff

diff --git a/src/library/scala/collection/Map.scala b/src/library/scala/collection/Map.scala
index 9187c7c041..704a0f7f3e 100644
--- a/src/library/scala/collection/Map.scala
+++ b/src/library/scala/collection/Map.scala
@@ -33,7 +33,7 @@ trait Map[K, +V]
     case that: Map[K, _] =>
       (this eq that) ||
       (that canEqual this) &&
-      (this.size == that.size) && {
+      (this.sizeCompare(that) == 0) && {
         try {
           val checker = new AbstractFunction1[(K, V),Boolean] {
             override def apply(kv: (K,V)): Boolean = {
diff --git a/src/library/scala/collection/Set.scala b/src/library/scala/collection/Set.scala
index d82117cc6a..daa004d8a1 100644
--- a/src/library/scala/collection/Set.scala
+++ b/src/library/scala/collection/Set.scala
@@ -31,7 +31,7 @@ trait Set[A]
       case set: Set[A] =>
         (this eq set) ||
           (set canEqual this) &&
-            (toIterable.size == set.size) &&
+            (toIterable.sizeCompare(set) == 0) &&
             (this subsetOf set)
       case _ => false
     }
diff --git a/src/library/scala/collection/immutable/IntMap.scala b/src/library/scala/collection/immutable/IntMap.scala
index f9a8e4233f..47116e0fcf 100644
--- a/src/library/scala/collection/immutable/IntMap.scala
+++ b/src/library/scala/collection/immutable/IntMap.scala
@@ -261,7 +261,7 @@ sealed abstract class IntMap[+T] extends AbstractMap[Int, T]

   override protected[this] def className = "IntMap"

-  override def isEmpty = this == IntMap.Nil
+  override def isEmpty = this eq IntMap.Nil
   override def knownSize: Int = if (isEmpty) 0 else super.knownSize
   override def filter(f: ((Int, T)) => Boolean): IntMap[T] = this match {
     case IntMap.Bin(prefix, mask, left, right) => {
diff --git a/src/library/scala/collection/immutable/LongMap.scala b/src/library/scala/collection/immutable/LongMap.scala
index 0d3524e600..d07b1277fe 100644
--- a/src/library/scala/collection/immutable/LongMap.scala
+++ b/src/library/scala/collection/immutable/LongMap.scala
@@ -256,7 +256,7 @@ sealed abstract class LongMap[+T] extends AbstractMap[Long, T]

   override protected[this] def className = "LongMap"

-  override def isEmpty = this == LongMap.Nil
+  override def isEmpty = this eq LongMap.Nil
   override def knownSize: Int = if (isEmpty) 0 else super.knownSize
   override def filter(f: ((Long, T)) => Boolean): LongMap[T] = this match {
     case LongMap.Bin(prefix, mask, left, right) => {