QMetaType: inline isValid() and isRegistered()

isValid() is (or could be) used in a lot of places, so make it inline.
One could effectively write it as:
    mt == QMetaType()
And rely on comparesEqual() knowing that an invalid type cannot equal to
a valid one.

I'm inlining isRegistered() because it's a simple function.

I chose to use the QT6_DECL_NEW_OVERLOAD technique instead of
QT_CORE_INLINED_SINCE because the latter does not apply inlining to
QtCore itself (aside from LTO).

Change-Id: I0e727ab80c42d51867d0fffd2f9641bc88f926b1
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/corelib/compat/removed_api.cpp

@@ -1245,6 +1245,18 @@ QUuid QUuid::createUuidV5(const QUuid &ns, const QByteArray &baseData) noexcept
 #endif // QT_CORE_REMOVED_SINCE(6, 8)
 
 #if QT_CORE_REMOVED_SINCE(6, 9)
+#include "qmetatype.h"
+
+bool QMetaType::isRegistered() const
+{
+    return isRegistered(QT6_CALL_NEW_OVERLOAD);
+}
+
+bool QMetaType::isValid() const
+{
+    return isValid(QT6_CALL_NEW_OVERLOAD);
+}
+
 
 #include "quuid.h"
 

src/corelib/kernel/qmetatype.cpp

@@ -512,10 +512,6 @@ const char *QtMetaTypePrivate::typedefNameForType(const QtPrivate::QMetaTypeInte
 
     \sa isRegistered()
 */
-bool QMetaType::isValid() const
-{
-    return d_ptr;
-}
 
 /*!
     \fn bool QMetaType::isRegistered() const
@@ -527,10 +523,6 @@ bool QMetaType::isValid() const
 
     \sa qRegisterMetaType(), isValid()
 */
-bool QMetaType::isRegistered() const
-{
-    return d_ptr && d_ptr->typeId.loadRelaxed();
-}
 
 /*!
     \fn int QMetaType::id() const

src/corelib/kernel/qmetatype.h

@@ -457,8 +457,12 @@ public:
     explicit constexpr QMetaType(const QtPrivate::QMetaTypeInterface *d) : d_ptr(d) {}
     constexpr QMetaType() = default;
 
+#if QT_CORE_REMOVED_SINCE(6, 9)
     bool isValid() const;
     bool isRegistered() const;
+#endif
+    constexpr bool isValid(QT6_DECL_NEW_OVERLOAD) const noexcept;
+    inline bool isRegistered(QT6_DECL_NEW_OVERLOAD) const noexcept;
     void registerType() const
     {
         // "register" is a reserved keyword
@@ -2640,6 +2644,16 @@ constexpr QMetaType QMetaType::fromType()
     return QMetaType(QtPrivate::qMetaTypeInterfaceForType<T>());
 }
 
+constexpr bool QMetaType::isValid(QT6_IMPL_NEW_OVERLOAD) const noexcept
+{
+    return d_ptr;
+}
+
+bool QMetaType::isRegistered(QT6_IMPL_NEW_OVERLOAD) const noexcept
+{
+    return d_ptr && d_ptr->typeId.loadRelaxed();
+}
+
 constexpr qsizetype QMetaType::sizeOf() const
 {
     return d_ptr ? d_ptr->size : 0;

src/corelib/kernel/qvariant.h

@@ -713,7 +713,7 @@ public:
 
 inline bool QVariant::isValid() const
 {
-    return d.type().isValid();
+    return d.type().isValid(QT6_CALL_NEW_OVERLOAD);
 }
 
 #ifndef QT_NO_DATASTREAM