QMetaType: Do not automatically register types that derives from a Q_GADGET

Otherwise the type is registered with the wrong name

Change-Id: I68ec3a05e2528816626e648b46ccc9d70b004866
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index b854dc16fd..9ad8702e79 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 *) };
     };