Move flatten and unzip to parts corresponding to the receiver type of operation.

libraries/stdlib/src/kotlin/collections/Arrays.kt

@@ -1,5 +1,7 @@
 package kotlin
 
+import java.util.*
+
 /**
  * Returns an array with the specified [size], where each element is calculated by calling the specified
  * [init] function. The `init` function returns an array element given its index.
@@ -19,3 +21,28 @@ public inline fun <reified T> Array(size: Int, init: (Int) -> T): Array<T> {
  */
 public inline fun <reified T> emptyArray(): Array<T> = arrayOfNulls<T>(0) as Array<T>
 
+/**
+ * Returns a single list of all elements from all arrays in the given array.
+ */
+public fun <T> Array<Array<out T>>.flatten(): List<T> {
+    val result = ArrayList<T>(sumBy { it.size() })
+    for (element in this) {
+        result.addAll(element)
+    }
+    return result
+}
+
+/**
+ * Returns a pair of lists, where
+ * *first* list is built from the first values of each pair from this array,
+ * *second* list is built from the second values of each pair from this array.
+ */
+public fun <T, R> Array<Pair<T, R>>.unzip(): Pair<List<T>, List<R>> {
+    val listT = ArrayList<T>(size())
+    val listR = ArrayList<R>(size())
+    for (pair in this) {
+        listT.add(pair.first)
+        listR.add(pair.second)
+    }
+    return listT to listR
+}

libraries/stdlib/src/kotlin/collections/JUtil.kt

@@ -246,3 +246,31 @@ private fun rangeCheck(size: Int, fromIndex: Int, toIndex: Int) {
         toIndex > size -> throw IndexOutOfBoundsException("toIndex ($toIndex) is greater than size ($size).")
     }
 }
+
+/**
+ * Returns a single list of all elements from all collections in the given collection.
+ */
+public fun <T> Iterable<Iterable<T>>.flatten(): List<T> {
+    val result = ArrayList<T>()
+    for (element in this) {
+        result.addAll(element)
+    }
+    return result
+}
+
+/**
+ * Returns a pair of lists, where
+ * *first* list is built from the first values of each pair from this collection,
+ * *second* list is built from the second values of each pair from this collection.
+ */
+public fun <T, R> Iterable<Pair<T, R>>.unzip(): Pair<List<T>, List<R>> {
+    val expectedSize = collectionSizeOrDefault(10)
+    val listT = ArrayList<T>(expectedSize)
+    val listR = ArrayList<R>(expectedSize)
+    for (pair in this) {
+        listT.add(pair.first)
+        listR.add(pair.second)
+    }
+    return listT to listR
+}
+

libraries/stdlib/src/kotlin/collections/Operations.kt

@@ -1,78 +0,0 @@
-package kotlin
-
-import java.util.ArrayList
-
-/**
- * Returns a single list of all elements from all collections in the given collection.
- */
-public fun <T> Iterable<Iterable<T>>.flatten(): List<T> {
-    val result = ArrayList<T>()
-    for (element in this) {
-        result.addAll(element)
-    }
-    return result
-}
-
-/**
- * Returns a sequence of all elements from all sequences in this sequence.
- */
-public fun <T> Sequence<Sequence<T>>.flatten(): Sequence<T> {
-    return MultiSequence(this)
-}
-
-/**
- * Returns a single list of all elements from all arrays in the given array.
- */
-public fun <T> Array<Array<out T>>.flatten(): List<T> {
-    val result = ArrayList<T>(sumBy { it.size() })
-    for (element in this) {
-        result.addAll(element)
-    }
-    return result
-}
-
-/**
- * Returns a pair of lists, where
- * *first* list is built from the first values of each pair from this collection,
- * *second* list is built from the second values of each pair from this collection.
- */
-public fun <T, R> Iterable<Pair<T, R>>.unzip(): Pair<List<T>, List<R>> {
-    val expectedSize = collectionSizeOrDefault(10)
-    val listT = ArrayList<T>(expectedSize)
-    val listR = ArrayList<R>(expectedSize)
-    for (pair in this) {
-        listT.add(pair.first)
-        listR.add(pair.second)
-    }
-    return listT to listR
-}
-
-/**
- * Returns a pair of lists, where
- * *first* list is built from the first values of each pair from this array,
- * *second* list is built from the second values of each pair from this array.
- */
-public fun <T, R> Array<Pair<T, R>>.unzip(): Pair<List<T>, List<R>> {
-    val listT = ArrayList<T>(size())
-    val listR = ArrayList<R>(size())
-    for (pair in this) {
-        listT.add(pair.first)
-        listR.add(pair.second)
-    }
-    return listT to listR
-}
-
-/**
- * Returns a pair of lists, where
- * *first* list is built from the first values of each pair from this sequence,
- * *second* list is built from the second values of each pair from this sequence.
- */
-public fun <T, R> Sequence<Pair<T, R>>.unzip(): Pair<List<T>, List<R>> {
-    val listT = ArrayList<T>()
-    val listR = ArrayList<R>()
-    for (pair in this) {
-        listT.add(pair.first)
-        listR.add(pair.second)
-    }
-    return listT to listR
-}

libraries/stdlib/src/kotlin/collections/Sequence.kt

@@ -65,6 +65,27 @@ private object EmptySequence : Sequence<Nothing> {
     override fun iterator(): Iterator<Nothing> = EmptyIterator
 }
 
+/**
+ * Returns a sequence of all elements from all sequences in this sequence.
+ */
+public fun <T> Sequence<Sequence<T>>.flatten(): Sequence<T> {
+    return MultiSequence(this)
+}
+/**
+ * Returns a pair of lists, where
+ * *first* list is built from the first values of each pair from this sequence,
+ * *second* list is built from the second values of each pair from this sequence.
+ */
+public fun <T, R> Sequence<Pair<T, R>>.unzip(): Pair<List<T>, List<R>> {
+    val listT = ArrayList<T>()
+    val listR = ArrayList<R>()
+    for (pair in this) {
+        listT.add(pair.first)
+        listR.add(pair.second)
+    }
+    return listT to listR
+}
+
 /**
  * A sequence that returns the values from the underlying [sequence] that either match or do not match
  * the specified [predicate].