From aabc00f53faa72f7c070c2512e655abffad37597 Mon Sep 17 00:00:00 2001
From: Abduqodiri Qurbonzoda <abduqodiri.qurbonzoda@jetbrains.com>
Date: Wed, 23 Jun 2021 19:37:59 +0300
Subject: [PATCH] Throw IllegalStateException from MapBuilder iterator.remove()
 #KT-47419

---
 .../stdlib/jvm/src/kotlin/collections/builders/MapBuilder.kt     | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libraries/stdlib/jvm/src/kotlin/collections/builders/MapBuilder.kt b/libraries/stdlib/jvm/src/kotlin/collections/builders/MapBuilder.kt
index 6185481c5db..61ef763b23e 100644
--- a/libraries/stdlib/jvm/src/kotlin/collections/builders/MapBuilder.kt
+++ b/libraries/stdlib/jvm/src/kotlin/collections/builders/MapBuilder.kt
@@ -459,6 +459,7 @@ internal class MapBuilder<K, V> private constructor(
         fun hasNext(): Boolean = index < map.length
 
         fun remove() {
+            check(lastIndex != -1) { "Call next() before removing element from the iterator." }
             map.checkIsMutable()
             map.removeKeyAt(lastIndex)
             lastIndex = -1