Fix compilation of Q_DECLARE_METATYPE(QVariant) by introducing QMetaType::QVariant

After 03daf059647c0a0222e8774b0a083f58c8e64934

With the recent change in QMetaType, qRegisterMetaType<T> instantiates
QMetaTypeId2<T>, which itself instantiates QMetaTypeId<T> if T is not
builtin into QMetaType.

But qRegisterMetaType<QVariant> is called in qvariant.h which makes
further call to Q_DECLARE_METATYPE(QVariant) to fail as
QMetaTypeId<QVariant> would have been instantied before

The solution is to make QVariant a builtin type.

Reviewed-by: Thierry

3 files changed, 20 insertions, 3 deletions

diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index be506b4..8f2d025 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -133,6 +133,7 @@ QT_BEGIN_NAMESPACE
     \value Float \c float
     \value QObjectStar QObject *
     \value QWidgetStar QWidget *
+    \value QVariant QVariant
 
     \value QColorGroup QColorGroup
     \value QCursor QCursor
@@ -300,6 +301,7 @@ static const struct { const char * typeName; int typeNameLength; int type; } typ
     QT_ADD_STATIC_METATYPE("float", QMetaType::Float),
     QT_ADD_STATIC_METATYPE("QObject*", QMetaType::QObjectStar),
     QT_ADD_STATIC_METATYPE("QWidget*", QMetaType::QWidgetStar),
+    QT_ADD_STATIC_METATYPE("QVariant", QMetaType::QVariant),
 
     /* Type aliases - order doesn't matter */
     QT_ADD_STATIC_METATYPE("unsigned long", QMetaType::ULong),
@@ -686,6 +688,9 @@ bool QMetaType::save(QDataStream &stream, int type, const void *data)
     case QMetaType::QVariantList:
         stream << *static_cast<const NS(QVariantList)*>(data);
         break;
+    case QMetaType::QVariant:
+        stream << *static_cast<const NS(QVariant)*>(data);
+        break;
 #endif
     case QMetaType::QByteArray:
         stream << *static_cast<const NS(QByteArray)*>(data);
@@ -888,6 +893,9 @@ bool QMetaType::load(QDataStream &stream, int type, void *data)
     case QMetaType::QVariantList:
         stream >> *static_cast< NS(QVariantList)*>(data);
         break;
+    case QMetaType::QVariant:
+        stream >> *static_cast< NS(QVariant)*>(data);
+        break;
 #endif
     case QMetaType::QByteArray:
         stream >> *static_cast< NS(QByteArray)*>(data);
@@ -1055,6 +1063,8 @@ void *QMetaType::construct(int type, const void *copy)
             return new NS(QVariantHash)(*static_cast<const NS(QVariantHash)*>(copy));
         case QMetaType::QVariantList:
             return new NS(QVariantList)(*static_cast<const NS(QVariantList)*>(copy));
+        case QMetaType::QVariant:
+            return new NS(QVariant)(*static_cast<const NS(QVariant)*>(copy));
 #endif
         case QMetaType::QByteArray:
             return new NS(QByteArray)(*static_cast<const NS(QByteArray)*>(copy));
@@ -1150,6 +1160,8 @@ void *QMetaType::construct(int type, const void *copy)
             return new NS(QVariantHash);
         case QMetaType::QVariantList:
             return new NS(QVariantList);
+        case QMetaType::QVariant:
+            return new NS(QVariant);
 #endif
         case QMetaType::QByteArray:
             return new NS(QByteArray);
@@ -1291,6 +1303,9 @@ void QMetaType::destroy(int type, void *data)
     case QMetaType::QVariantList:
         delete static_cast< NS(QVariantList)* >(data);
         break;
+    case QMetaType::QVariant:
+        delete static_cast< NS(QVariant)* >(data);
+        break;
 #endif
     case QMetaType::QByteArray:
         delete static_cast< NS(QByteArray)* >(data);
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 2ed4a1f..98ed4bd 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -86,7 +86,8 @@ public:
         FirstCoreExtType = 128 /* VoidStar */,
         VoidStar = 128, Long = 129, Short = 130, Char = 131, ULong = 132,
         UShort = 133, UChar = 134, Float = 135, QObjectStar = 136, QWidgetStar = 137,
-        LastCoreExtType = QWidgetStar,
+        QVariant = 138,
+        LastCoreExtType = QVariant,
 
 // This logic must match the one in qglobal.h
 #if defined(QT_COORD_TYPE)
@@ -353,6 +354,7 @@ class QVector2D;
 class QVector3D;
 class QVector4D;
 class QQuaternion;
+class QVariant;
 
 QT_END_NAMESPACE
 
@@ -421,6 +423,7 @@ Q_DECLARE_BUILTIN_METATYPE(QVector2D, QVector2D)
 Q_DECLARE_BUILTIN_METATYPE(QVector3D, QVector3D)
 Q_DECLARE_BUILTIN_METATYPE(QVector4D, QVector4D)
 Q_DECLARE_BUILTIN_METATYPE(QQuaternion, QQuaternion)
+Q_DECLARE_BUILTIN_METATYPE(QVariant, QVariant)
 
 QT_END_HEADER
 
diff --git a/src/corelib/kernel/qvariant.h b/src/corelib/kernel/qvariant.h
index 9628dbf..cb2825c 100644
--- a/src/corelib/kernel/qvariant.h
+++ b/src/corelib/kernel/qvariant.h
@@ -589,8 +589,7 @@ template<typename T> inline T qvariant_cast(const QVariant &v)
 
 template<> inline QVariant qvariant_cast<QVariant>(const QVariant &v)
 {
-    static const int vid = qRegisterMetaType<QVariant>("QVariant");
-    if (vid == v.userType())
+    if (v.userType() == QMetaType::QVariant)
         return *reinterpret_cast<const QVariant *>(v.constData());
     return v;
 }