Fix memory leak in QtConcurrent::run when called with a NULL QThreadPool

QThreadPool automatically deletes the runnable after it finishes running
the task. In case QThreadPool is nullptr, we should delete the runnable
manually. This amends 87b93c29be02f0a7ff9424b5e2b6431e20bd4c40.

Pick-to: 6.3 6.2 5.15
Change-Id: Id7e4ed3d4d6de05990edf62e4099852983debc64
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/concurrent/qtconcurrentrunbase.h b/src/concurrent/qtconcurrentrunbase.h
index 4870362146..e21f636700 100644
--- a/src/concurrent/qtconcurrentrunbase.h
+++ b/src/concurrent/qtconcurrentrunbase.h
@@ -99,6 +99,7 @@ public:
         } else {
             promise.reportCanceled();
             promise.reportFinished();
+            delete this;
         }
         return theFuture;
     }