SemanticHighlighter: Fix off-by-one in assert.

Change-Id: Ie9331d233894e49cf86605819687eeef765272df
Reviewed-on: http://codereview.qt-project.org/5067
Reviewed-by: Leandro T. C. Melo <leandro.melo@nokia.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/plugins/texteditor/semantichighlighter.cpp b/src/plugins/texteditor/semantichighlighter.cpp
index 0e541e8f41..ba36dc9c1a 100644
--- a/src/plugins/texteditor/semantichighlighter.cpp
+++ b/src/plugins/texteditor/semantichighlighter.cpp
@@ -125,8 +125,13 @@ void TextEditor::SemanticHighlighter::clearExtraAdditionalFormatsUntilEnd(
     }
 
     QTextDocument *doc = highlighter->document();
-    QTC_ASSERT(lastBlockNumber + 1 < doc->blockCount(), return);
-    QTextBlock b = doc->findBlockByNumber(lastBlockNumber + 1);
+
+    const int firstBlockToClear = lastBlockNumber + 1;
+    if (firstBlockToClear == doc->blockCount())
+        return;
+    QTC_ASSERT(firstBlockToClear < doc->blockCount(), return);
+
+    QTextBlock b = doc->findBlockByNumber(firstBlockToClear);
 
     while (b.isValid()) {
         highlighter->setExtraAdditionalFormats(b, QList<QTextLayout::FormatRange>());