From 5aa415c609d96d2661fd945dcd81e8b11e6a8ab3 Mon Sep 17 00:00:00 2001
From: Ilya Gorbunov <ilya.gorbunov@jetbrains.com>
Date: Fri, 20 Nov 2015 22:49:09 +0300
Subject: [PATCH] MutableMap.iterator() returns MutableIterator.

---
 libraries/stdlib/src/kotlin/collections/Maps.kt |  8 ++++++++
 libraries/stdlib/test/collections/MapJVMTest.kt | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/libraries/stdlib/src/kotlin/collections/Maps.kt b/libraries/stdlib/src/kotlin/collections/Maps.kt
index 2b0aaec4744..ef6aae7dafa 100644
--- a/libraries/stdlib/src/kotlin/collections/Maps.kt
+++ b/libraries/stdlib/src/kotlin/collections/Maps.kt
@@ -190,6 +190,14 @@ public inline fun <K, V> MutableMap<K, V>.getOrPut(key: K, defaultValue: () -> V
  */
 public operator fun <K, V> Map<K, V>.iterator(): Iterator<Map.Entry<K, V>> = entries.iterator()
 
+/**
+ * Returns a [MutableIterator] over the mutable entries in the [MutableMap].
+ *
+ */
+@JvmVersion
+@JvmName("mutableIterator")
+public operator fun <K, V> MutableMap<K, V>.iterator(): MutableIterator<MutableMap.MutableEntry<K, V>> = entries.iterator()
+
 /**
  * Populates the given `destination` [Map] with entries having the keys of this map and the values obtained
  * by applying the `transform` function to each entry in this [Map].
diff --git a/libraries/stdlib/test/collections/MapJVMTest.kt b/libraries/stdlib/test/collections/MapJVMTest.kt
index 909a99e72b0..a531ec034bd 100644
--- a/libraries/stdlib/test/collections/MapJVMTest.kt
+++ b/libraries/stdlib/test/collections/MapJVMTest.kt
@@ -41,6 +41,17 @@ class MapJVMTest {
         assertEquals("B", prop.getProperty("b", "fail"))
     }
 
+    @test fun iterateAndRemove() {
+        val map = (1..5).toMap({ it }, { 'a' + it }).toLinkedMap()
+        val iterator = map.iterator()
+        while (iterator.hasNext()) {
+            if (iterator.next().key % 2 == 0)
+                iterator.remove()
+        }
+        assertEquals(listOf(1, 3, 5), map.keys.toList())
+        assertEquals(listOf('b', 'd', 'f'), map.values.toList())
+    }
+
     @test fun getOrPutFailsOnConcurrentMap() {
         val map = ConcurrentHashMap<String, Int>()