Merge remote-tracking branch 'origin/5.7' into dev

Conflicts:
	config_help.txt
	configure
	src/corelib/io/qprocess_wince.cpp
	src/plugins/platforms/windows/qwindowstheme.cpp
	src/plugins/platforms/xcb/qxcbbackingstore.cpp
	tests/auto/corelib/tools/qtimezone/BLACKLIST
	tests/auto/network/socket/qudpsocket/tst_qudpsocket.cpp
	tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp

Change-Id: I26644d1cb3b78412c8ff285e2a55bea1bd641c01

1 files changed, 9 insertions, 5 deletions

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 5e3016d313..b15dc7b07b 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -554,11 +554,15 @@ QHash<Key, T>::createNode(uint ah, const Key &akey, const T &avalue, Node **anex
 template <class Key, class T>
 Q_INLINE_TEMPLATE QHash<Key, T> &QHash<Key, T>::unite(const QHash &other)
 {
-    QHash copy(other);
-    const_iterator it = copy.constEnd();
-    while (it != copy.constBegin()) {
-        --it;
-        insertMulti(it.key(), it.value());
+    if (d == &QHashData::shared_null) {
+        *this = other;
+    } else {
+        QHash copy(other);
+        const_iterator it = copy.constEnd();
+        while (it != copy.constBegin()) {
+            --it;
+            insertMulti(it.key(), it.value());
+        }
     }
     return *this;
 }