From 377988cb7bba50ce0550df43f1086654b830b5ad Mon Sep 17 00:00:00 2001
From: Ilya Ryzhenkov <orangy@jetbrains.com>
Date: Mon, 22 Dec 2014 22:22:33 +0300
Subject: [PATCH] toSortedMap() without comparator requires non-null keys
 #KT-6509 Fixed

---
 libraries/stdlib/src/kotlin/collections/MapsJVM.kt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/stdlib/src/kotlin/collections/MapsJVM.kt b/libraries/stdlib/src/kotlin/collections/MapsJVM.kt
index 41fad88f2bd..33f01fd967d 100644
--- a/libraries/stdlib/src/kotlin/collections/MapsJVM.kt
+++ b/libraries/stdlib/src/kotlin/collections/MapsJVM.kt
@@ -15,7 +15,7 @@ public fun <K, V> MutableMap<K, V>.set(key: K, value: V): V? = put(key, value)
  *
  * @includeFunctionBody ../../test/collections/MapTest.kt toSortedMap
  */
-public fun <K, V> Map<K, V>.toSortedMap(): SortedMap<K, V> = TreeMap(this)
+public fun <K : Any, V> Map<K, V>.toSortedMap(): SortedMap<K, V> = TreeMap(this)
 
 /**
  * Converts this [[Map]] to a [[SortedMap]] using the given *comparator* so that iteration order will be in the order