diff --git a/platform/core-impl/src/com/intellij/psi/impl/source/tree/TreeUtil.java b/platform/core-impl/src/com/intellij/psi/impl/source/tree/TreeUtil.java
index dfd17fc47728..9b3ece54e05b 100644
--- a/platform/core-impl/src/com/intellij/psi/impl/source/tree/TreeUtil.java
+++ b/platform/core-impl/src/com/intellij/psi/impl/source/tree/TreeUtil.java
@@ -1,18 +1,4 @@
-/*
- * Copyright 2000-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 
 package com.intellij.psi.impl.source.tree;
 
@@ -442,12 +428,12 @@ public class TreeUtil {
   }
 
   @Nullable
-  public static ASTNode skipWhitespaceAndComments(final ASTNode node, boolean forward) {
+  public static ASTNode skipWhitespaceAndComments(@Nullable ASTNode node, boolean forward) {
     return skipWhitespaceCommentsAndTokens(node, TokenSet.EMPTY, forward);
   }
 
   @Nullable
-  public static ASTNode skipWhitespaceCommentsAndTokens(final ASTNode node, @NotNull TokenSet alsoSkip, boolean forward) {
+  public static ASTNode skipWhitespaceCommentsAndTokens(@Nullable ASTNode node, @NotNull TokenSet alsoSkip, boolean forward) {
     ASTNode element = node;
     while (true) {
       if (element == null) return null;
@@ -457,7 +443,7 @@ public class TreeUtil {
     return element;
   }
 
-  public static boolean isWhitespaceOrComment(ASTNode element) {
+  public static boolean isWhitespaceOrComment(@NotNull ASTNode element) {
     return element.getPsi() instanceof PsiWhiteSpace || element.getPsi() instanceof PsiComment;
   }
 }
diff --git a/platform/lang-impl/src/com/intellij/codeInsight/editorActions/ExtendWordSelectionHandlerBase.java b/platform/lang-impl/src/com/intellij/codeInsight/editorActions/ExtendWordSelectionHandlerBase.java
index 81ea83c8f338..05f1bf395731 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/editorActions/ExtendWordSelectionHandlerBase.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/editorActions/ExtendWordSelectionHandlerBase.java
@@ -66,7 +66,8 @@ public abstract class ExtendWordSelectionHandlerBase implements ExtendWordSelect
     return 0;
   }
 
-  public static List<TextRange> expandToWholeLine(CharSequence text, @Nullable TextRange range, boolean isSymmetric) {
+  @NotNull
+  public static List<TextRange> expandToWholeLine(@NotNull CharSequence text, @Nullable TextRange range, boolean isSymmetric) {
     List<TextRange> result = new ArrayList<>();
 
     if (range == null) {
@@ -88,7 +89,7 @@ public abstract class ExtendWordSelectionHandlerBase implements ExtendWordSelect
   }
 
   @Nullable
-  private static TextRange getExpandedRange(CharSequence text, TextRange range, boolean isSymmetric) {
+  private static TextRange getExpandedRange(@NotNull CharSequence text, @NotNull TextRange range, boolean isSymmetric) {
     int startOffset = range.getStartOffset();
     int endOffset = range.getEndOffset();
     int index1 = CharArrayUtil.shiftBackward(text, startOffset - 1, " \t");
@@ -128,7 +129,8 @@ public abstract class ExtendWordSelectionHandlerBase implements ExtendWordSelect
     return null;
   }
 
-  public static List<TextRange> expandToWholeLinesWithBlanks(CharSequence text, TextRange range) {
+  @NotNull
+  public static List<TextRange> expandToWholeLinesWithBlanks(@NotNull CharSequence text, @NotNull TextRange range) {
     List<TextRange> result = ContainerUtil.newArrayList();
     result.addAll(expandToWholeLine(text, range, true));
 
@@ -158,7 +160,8 @@ public abstract class ExtendWordSelectionHandlerBase implements ExtendWordSelect
     return result;
   }
 
-  public static List<TextRange> expandToWholeLine(CharSequence text, TextRange range) {
+  @NotNull
+  public static List<TextRange> expandToWholeLine(@NotNull CharSequence text, @Nullable TextRange range) {
     return expandToWholeLine(text, range, true);
   }
 }
\ No newline at end of file