diff --git a/examples/widgets/tools/treemodelcompleter/mainwindow.cpp b/examples/widgets/tools/treemodelcompleter/mainwindow.cpp
index c00e058fc4f..4aabb040235 100644
--- a/examples/widgets/tools/treemodelcompleter/mainwindow.cpp
+++ b/examples/widgets/tools/treemodelcompleter/mainwindow.cpp
@@ -194,16 +194,17 @@ QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
         if (line.isEmpty() || trimmedLine.isEmpty())
             continue;
 
-        QRegExp re("^\\s+");
-        int nonws = re.indexIn(line);
+        QRegularExpression re("^\\s+");
+        QRegularExpressionMatch match = re.match(line);
+        int nonws = match.capturedStart();
         int level = 0;
         if (nonws == -1) {
             level = 0;
         } else {
             if (line.startsWith("\t")) {
-                level = re.cap(0).length();
+                level = match.capturedLength();
             } else {
-                level = re.cap(0).length()/4;
+                level = match.capturedLength()/4;
             }
         }