From d97c949229f39eea86212f7ea8f3888646997def Mon Sep 17 00:00:00 2001
From: Ilya Ryzhenkov <ilya.ryzhenkov@jetbrains.com>
Date: Fri, 29 Jul 2016 21:05:40 +0300
Subject: [PATCH] MergingCharSequence::subSequence optimization

---
 .../util/src/com/intellij/util/text/MergingCharSequence.java     | 1 +
 1 file changed, 1 insertion(+)

diff --git a/platform/util/src/com/intellij/util/text/MergingCharSequence.java b/platform/util/src/com/intellij/util/text/MergingCharSequence.java
index 0b7e4db0bb05..a0358ab8e86e 100644
--- a/platform/util/src/com/intellij/util/text/MergingCharSequence.java
+++ b/platform/util/src/com/intellij/util/text/MergingCharSequence.java
@@ -42,6 +42,7 @@ public class MergingCharSequence implements CharSequence {
 
   @Override
   public CharSequence subSequence(int start, int end) {
+    if (start == 0 && end == length()) return this;
     if (start < s1.length() && end < s1.length()) return s1.subSequence(start, end);
     if (start >= s1.length() && end >= s1.length()) return s2.subSequence(start - s1.length(), end - s1.length());
     return new MergingCharSequence(s1.subSequence(start, s1.length()), s2.subSequence(0, end - s1.length()));