Merge remote-tracking branch 'qt/dev' into dev-highdpi

Conflicts:
	src/gui/kernel/qsimpledrag.cpp
	src/gui/kernel/qwindowsysteminterface.cpp
	src/gui/kernel/qwindowsysteminterface_p.h
	src/plugins/platforms/xcb/qxcbwindow.cpp

Change-Id: Icd887552ade61d6a2b2527383970f7145aa00faf

1 files changed, 10 insertions, 5 deletions

diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 1e2a860d8c..1b214e9f74 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -1357,12 +1357,16 @@ namespace QtPrivate
         enum { Value = sizeof(checkType(static_cast<T*>(0))) == sizeof(yes_type) };
     };
 
+    template<typename T, typename Enable = void>
+    struct IsGadgetHelper { enum { Value = false }; };
+
     template<typename T>
-    struct IsGadgetHelper
+    struct IsGadgetHelper<T, typename T::QtGadgetHelper>
     {
-        template<typename X> static typename X::QtGadgetHelper *checkType(X*);
-        static char checkType(void*);
-        enum { Value = sizeof(checkType(static_cast<T*>(0))) == sizeof(void*)  };
+        template <typename X>
+        static char checkType(void (X::*)());
+        static void *checkType(void (T::*)());
+        enum { Value =  sizeof(checkType(&T::qt_check_for_QGADGET_macro)) == sizeof(void *) };
     };
 
 
@@ -1381,6 +1385,7 @@ QT_WARNING_DISABLE_CLANG("-Wlocal-type-template-args")
         // qt_getEnumMetaObject(T) which returns 'char'
         enum { Value = sizeof(qt_getEnumMetaObject(declval())) == sizeof(QMetaObject*) };
     };
+    template<> struct IsQEnumHelper<void> { enum { Value = false }; };
 QT_WARNING_POP
 
     template<typename T, typename Enable = void>
@@ -1768,7 +1773,7 @@ template <typename T>
 struct QMetaTypeIdQObject<T, QMetaType::IsGadget>
 {
     enum {
-        Defined = 1
+        Defined = QtPrivate::is_default_constructible<T>::value
     };
 
     static int qt_metatype_id()