Polish the SimpleTreeModel example

- Fix/silence most clang-tidy/compiler warnings
  * unsigned/int comparison
  * Avoid repeating return / default parameter types
  * Make functions static/use static invocations
  * Use string literals everywhere
  * Use auto * for pointers
  * Streamline code, use ternary operators
  * Move constructor parameters
  * Observe rule of 5 by using Q_DISABLE_COPY_MOVE
- Add some bells && whistles, resize properly, expand all

Complements 25027444a9b53d61a6257dc5f5ce0ffdb3b06f98.

Pick-to: 6.6
Change-Id: I78f48d187981ecabf69a5d4d42715bad026fa9e6
Reviewed-by: Kai Köhne <kai.koehne@qt.io>

1 files changed, 1 insertions, 1 deletions

diff --git a/examples/widgets/itemviews/simpletreemodel/treeitem.h b/examples/widgets/itemviews/simpletreemodel/treeitem.h
index 8edebcc34b..b9002f06fd 100644
--- a/examples/widgets/itemviews/simpletreemodel/treeitem.h
+++ b/examples/widgets/itemviews/simpletreemodel/treeitem.h
@@ -11,7 +11,7 @@
 class TreeItem
 {
 public:
-    explicit TreeItem(const QVariantList &data, TreeItem *parentItem = nullptr);
+    explicit TreeItem(QVariantList data, TreeItem *parentItem = nullptr);
 
     void appendChild(std::unique_ptr<TreeItem> &&child);