Avoid UB in QList::removeAt()

Always keep the out of bounds check for backwards compatibility,
but warn about it, so that we can remove it in Qt 6.

Amends commit ebf695bc779a63a5730df05ab246305c0ab342e4

Change-Id: I3f1e7e8f9f20feb0b0f06ff9083c26682f1c7d3b
Reviewed-by: Richard Öhlinger <richard.oehlinger@adbsafegate.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index 37258cc66f..8a11663c01 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -583,10 +583,13 @@ inline void QList<T>::removeAt(int i)
 {
 #if !QT_DEPRECATED_SINCE(5, 15)
     Q_ASSERT_X(i >= 0 && i < p.size(), "QList<T>::removeAt", "index out of range");
-#elif !defined(QT_NO_DEBUG)
-    if (i < 0 || i >= p.size())
+#endif
+    if (i < 0 || i >= p.size()) {
+#if !defined(QT_NO_DEBUG)
         qWarning("QList::removeAt(): Index out of range.");
 #endif
+        return;
+    }
     detach();
     node_destruct(reinterpret_cast<Node *>(p.at(i))); p.remove(i);
 }