diff --git a/src/qtpromise/qpromise_p.h b/src/qtpromise/qpromise_p.h
index f2012a5..c97e63d 100644
--- a/src/qtpromise/qpromise_p.h
+++ b/src/qtpromise/qpromise_p.h
@@ -32,7 +32,7 @@ namespace QtPromisePrivate {
 
 // https://stackoverflow.com/a/21653558
 template <typename F>
-static void qtpromise_defer(F&& f, QThread* thread = nullptr)
+static void qtpromise_defer(F&& f, const QPointer<QThread>& thread)
 {
     struct Event : public QEvent
     {
@@ -43,11 +43,34 @@ static void qtpromise_defer(F&& f, QThread* thread = nullptr)
         FType m_f;
     };
 
+    if (!thread || thread->isFinished()) {
+        // Make sure to not call `f` if the captured thread doesn't exist anymore,
+        // which would potentially result in dispatching to the wrong thread (ie.
+        // nullptr == current thread). Since the target thread is gone, it should
+        // be safe to simply skip that notification.
+        return;
+    }
+
     QObject* target = QAbstractEventDispatcher::instance(thread);
+    if (!target && QCoreApplication::closingDown()) {
+        // When the app is shutting down, the even loop is not anymore available
+        // so we don't have any way to dispatch `f`. This case can happen when a
+        // promise is resolved after the app is requested to close, in which case
+        // we should not trigger any error and skip that notification.
+        return;
+    }
+
     Q_ASSERT_X(target, "postMetaCall", "Target thread must have an event loop");
     QCoreApplication::postEvent(target, new Event(std::forward<F>(f)));
 }
 
+template <typename F>
+static void qtpromise_defer(F&& f)
+{
+    Q_ASSERT(QThread::currentThread());
+    qtpromise_defer(std::forward<F>(f), QThread::currentThread());
+}
+
 template <typename T>
 struct PromiseDeduce
 {
diff --git a/tests/auto/qtpromise/future/tst_future.cpp b/tests/auto/qtpromise/future/tst_future.cpp
index 072d287..0508ac8 100644
--- a/tests/auto/qtpromise/future/tst_future.cpp
+++ b/tests/auto/qtpromise/future/tst_future.cpp
@@ -261,9 +261,9 @@ void tst_future::fail()
     QString result;
     auto input = QPromise<QString>::reject(MyException("bar"));
     auto output = input.fail([](const MyException& e) {
-        return QtConcurrent::run([=]() {
-            return QString("foo%1").arg(e.error());
-        });
+        return QtConcurrent::run([](const QString& error) {
+            return QString("foo%1").arg(error);
+        }, e.error());
     });
 
     QCOMPARE(input.isRejected(), true);
@@ -282,9 +282,9 @@ void tst_future::fail_void()
     QString result;
     auto input = QPromise<void>::reject(MyException("bar"));
     auto output = input.fail([&](const MyException& e) {
-        return QtConcurrent::run([&]() {
-            result = e.error();
-        });
+        return QtConcurrent::run([&](const QString& error) {
+            result = error;
+        }, e.error());
     });
 
     QCOMPARE(input.isRejected(), true);