diff --git a/platform/editor-ui-ex/src/com/intellij/psi/impl/search/IndexPatternSearcher.java b/platform/editor-ui-ex/src/com/intellij/psi/impl/search/IndexPatternSearcher.java
index 846b0c1de91d..9b9bdc1ee552 100644
--- a/platform/editor-ui-ex/src/com/intellij/psi/impl/search/IndexPatternSearcher.java
+++ b/platform/editor-ui-ex/src/com/intellij/psi/impl/search/IndexPatternSearcher.java
@@ -25,6 +25,7 @@ import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.tree.TokenSet;
 import com.intellij.util.Processor;
 import com.intellij.util.QueryExecutor;
+import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.text.CharArrayUtil;
 import com.intellij.util.text.CharSequenceSubSequence;
 import gnu.trove.TIntArrayList;
@@ -135,55 +136,11 @@ public class IndexPatternSearcher implements QueryExecutor<IndexPatternOccurrenc
   }
 
   private static void mergeCommentLists(List<CommentRange> target, List<CommentRange> source) {
-    if (target.isEmpty()) {
-      target.addAll(source);
-      return;
-    }
-
-    mergeSortedArrays(target, source);
-  }
-
-  /**
-   * Merge sorted points, which are sorted by x and with equal x by y.
-   * Result is put to x1 y1.
-   */
-  static void mergeSortedArrays(@NotNull List<CommentRange> target, @NotNull List<CommentRange> source) {
-    List<CommentRange> result = new ArrayList<>();
-
-    int i = 0;
-    int j = 0;
-
-    while (i < target.size() && j < source.size()) {
-      CommentRange targetRange = target.get(i);
-      CommentRange sourceRange = source.get(j);
-      if (targetRange.startOffset < sourceRange.startOffset ||
-          targetRange.startOffset == sourceRange.startOffset && targetRange.endOffset < sourceRange.endOffset) {
-        result.add(targetRange);
-        i++;
-      }
-      else if (targetRange.startOffset > sourceRange.startOffset || targetRange.endOffset > sourceRange.endOffset) {
-        result.add(sourceRange);
-        j++;
-      }
-      else { //equals
-        result.add(targetRange);
-        i++;
-        j++;
-      }
-    }
-
-    while (i < target.size()) {
-      result.add(target.get(i));
-      i++;
-    }
-
-    while (j < source.size()) {
-      result.add(source.get(j));
-      j++;
-    }
-
+    List<CommentRange> merged = target.isEmpty()
+                                ? source
+                                : ContainerUtil.mergeSortedLists(target, source, CommentRange.BY_START_OFFSET_THEN_BY_END_OFFSET, true);
     target.clear();
-    target.addAll(result);
+    target.addAll(merged);
   }
 
   private static List<CommentRange> findComments(final Lexer lexer,
@@ -345,12 +302,15 @@ public class IndexPatternSearcher implements QueryExecutor<IndexPatternOccurrenc
     return result.isEmpty() ? Collections.emptyList() : result;
   }
 
-  static class CommentRange {
+  private static class CommentRange {
+    private static final Comparator<CommentRange> BY_START_OFFSET_THEN_BY_END_OFFSET =
+      Comparator.comparingInt((CommentRange o) -> o.startOffset).thenComparingInt((CommentRange o) -> o.endOffset);
+
     private final int startOffset;
     private final int endOffset;
     private final String allowedContinuationPrefixChars;
 
-    CommentRange(int startOffset, int endOffset) {
+    private CommentRange(int startOffset, int endOffset) {
       this(startOffset, endOffset, "");
     }
 
@@ -359,20 +319,5 @@ public class IndexPatternSearcher implements QueryExecutor<IndexPatternOccurrenc
       this.endOffset = endOffset;
       allowedContinuationPrefixChars = chars;
     }
-
-    @Override
-    public boolean equals(Object o) {
-      if (this == o) return true;
-      if (o == null || getClass() != o.getClass()) return false;
-      CommentRange that = (CommentRange)o;
-      return startOffset == that.startOffset &&
-             endOffset == that.endOffset &&
-             Objects.equals(allowedContinuationPrefixChars, that.allowedContinuationPrefixChars);
-    }
-
-    @Override
-    public int hashCode() {
-      return Objects.hash(startOffset, endOffset, allowedContinuationPrefixChars);
-    }
   }
 }
diff --git a/platform/platform-tests/testSrc/com/intellij/psi/impl/search/LowLevelSearchUtilTest.java b/platform/platform-tests/testSrc/com/intellij/psi/impl/search/LowLevelSearchUtilTest.java
index 1a15ba88e155..29ca17767409 100644
--- a/platform/platform-tests/testSrc/com/intellij/psi/impl/search/LowLevelSearchUtilTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/psi/impl/search/LowLevelSearchUtilTest.java
@@ -2,16 +2,11 @@
 package com.intellij.psi.impl.search;
 
 import com.intellij.openapi.util.text.StringUtil;
-import com.intellij.psi.impl.search.IndexPatternSearcher.CommentRange;
 import com.intellij.testFramework.PlatformTestUtil;
 import com.intellij.util.text.StringSearcher;
 import gnu.trove.TIntArrayList;
 import junit.framework.TestCase;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-
 /**
  * @author yole
  */
@@ -65,52 +60,4 @@ public class LowLevelSearchUtilTest extends TestCase {
       }
     }).assertTiming();
   }
-
-  public void testMergeSortedArrays() {
-    List<CommentRange> target = new ArrayList<>(Arrays.asList(
-      new CommentRange(0, 0),
-      new CommentRange(2, 2),
-      new CommentRange(4, 4),
-      new CommentRange(6, 6)
-    ));
-    List<CommentRange> source = Arrays.asList(
-      new CommentRange(1, 1),
-      new CommentRange(2, 2),
-      new CommentRange(2, 3)
-    );
-    IndexPatternSearcher.mergeSortedArrays(target, source);
-    assertEquals(Arrays.asList(
-      new CommentRange(0, 0),
-      new CommentRange(1, 1),
-      new CommentRange(2, 2),
-      new CommentRange(2, 3),
-      new CommentRange(4, 4),
-      new CommentRange(6, 6)
-    ), target);
-    IndexPatternSearcher.mergeSortedArrays(target, source);
-    assertEquals(Arrays.asList(
-      new CommentRange(0, 0),
-      new CommentRange(1, 1),
-      new CommentRange(2, 2),
-      new CommentRange(2, 3),
-      new CommentRange(4, 4),
-      new CommentRange(6, 6)
-    ), target);
-    IndexPatternSearcher.mergeSortedArrays(target, Arrays.asList(
-      new CommentRange(-1, -1),
-      new CommentRange(-1, -2),
-      new CommentRange(-2, -3)
-    ));
-    assertEquals(Arrays.asList(
-      new CommentRange(-1, -1),
-      new CommentRange(-1, -2),
-      new CommentRange(-2, -3),
-      new CommentRange(0, 0),
-      new CommentRange(1, 1),
-      new CommentRange(2, 2),
-      new CommentRange(2, 3),
-      new CommentRange(4, 4),
-      new CommentRange(6, 6)
-    ), target);
-  }
 }
diff --git a/platform/platform-tests/testSrc/com/intellij/util/containers/ContainerUtilTest.java b/platform/platform-tests/testSrc/com/intellij/util/containers/ContainerUtilTest.java
index 732637fb1868..f6d2578706a8 100644
--- a/platform/platform-tests/testSrc/com/intellij/util/containers/ContainerUtilTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/util/containers/ContainerUtilTest.java
@@ -16,6 +16,8 @@
 package com.intellij.util.containers;
 
 import com.intellij.openapi.util.Condition;
+import com.intellij.openapi.util.Segment;
+import com.intellij.openapi.util.UnfairTextRange;
 import com.intellij.testFramework.PlatformTestUtil;
 import com.intellij.util.ArrayUtil;
 import one.util.streamex.IntStreamEx;
@@ -241,4 +243,61 @@ public class ContainerUtilTest {
     List<String> actual = ContainerUtil.newArrayList(value);
     assertEquals(expected, actual);
   }
+
+  @Test
+  public void testMergeSortedLists() {
+    List<Segment> target = new ArrayList<>(Arrays.asList(
+      range(0, 0),
+      range(2, 2),
+      range(4, 4),
+      range(6, 6)
+    ));
+    List<Segment> source = Arrays.asList(
+      range(1, 1),
+      range(2, 2),
+      range(2, 3)
+    );
+    target = mergeSegmentLists(target, source);
+    assertEquals(Arrays.asList(
+      range(0, 0),
+      range(1, 1),
+      range(2, 2),
+      range(2, 3),
+      range(4, 4),
+      range(6, 6)
+    ), target);
+    target = mergeSegmentLists(target, source);
+    assertEquals(Arrays.asList(
+      range(0, 0),
+      range(1, 1),
+      range(2, 2),
+      range(2, 3),
+      range(4, 4),
+      range(6, 6)
+    ), target);
+    target = mergeSegmentLists(target, Arrays.asList(
+      range(-1, -1),
+      range(-1, -2),
+      range(-2, -3)
+    ));
+    assertEquals(Arrays.asList(
+      range(-1, -1),
+      range(-1, -2),
+      range(-2, -3),
+      range(0, 0),
+      range(1, 1),
+      range(2, 2),
+      range(2, 3),
+      range(4, 4),
+      range(6, 6)
+    ), target);
+  }
+
+  private static Segment range(int start, int end) {
+    return new UnfairTextRange(start, end);
+  }
+
+  private static List<Segment> mergeSegmentLists(List<Segment> list1, List<Segment> list2) {
+    return ContainerUtil.mergeSortedLists(list1, list2, Segment.BY_START_OFFSET_THEN_END_OFFSET, true);
+  }
 }
\ No newline at end of file
diff --git a/platform/util/src/com/intellij/util/containers/ContainerUtil.java b/platform/util/src/com/intellij/util/containers/ContainerUtil.java
index bf9ffdde5079..dc77461ab89a 100644
--- a/platform/util/src/com/intellij/util/containers/ContainerUtil.java
+++ b/platform/util/src/com/intellij/util/containers/ContainerUtil.java
@@ -637,7 +637,18 @@ public class ContainerUtil extends ContainerUtilRt {
         T element1 = list1.get(index1);
         T element2 = list2.get(index2);
         int c = comparator.compare(element1, element2);
-        if (c <= 0) {
+        if (c == 0) {
+          index1++;
+          index2++;
+          if (mergeEqualItems) {
+            e = element1;
+          }
+          else {
+            processor.consume(element1);
+            e = element2;
+          }
+        }
+        else if (c < 0) {
           e = element1;
           index1++;
         }
@@ -645,11 +656,6 @@ public class ContainerUtil extends ContainerUtilRt {
           e = element2;
           index2++;
         }
-        if (c == 0 && !mergeEqualItems) {
-          processor.consume(e);
-          index2++;
-          e = element2;
-        }
       }
       processor.consume(e);
     }