Smart pointers: port to explicit operator bool

Enough with the restricted bool trick; use the established solution.

[ChangeLog][Potentially Source-Incompatible Changes] QScopedPointer,
QSharedPointer and QWeakPointer's conversion operator towards bool
is now explicit. In some cases this may require an explicit cast
towards bool that was not needed before (notably, when returning
an object of these types from a function that actually returns bool).

Change-Id: I02b89278e75b7e7493ee7e35460504719e00f028
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qscopedpointer.h

@@ -95,7 +95,6 @@ typedef QScopedPointerObjectDeleteLater<QObject> QScopedPointerDeleteLater;
 template <typename T, typename Cleanup = QScopedPointerDeleter<T> >
 class QScopedPointer
 {
-    typedef T *QScopedPointer:: *RestrictedBool;
 public:
     explicit QScopedPointer(T *p = nullptr) noexcept : d(p)
     {
@@ -123,17 +122,10 @@ public:
         return !d;
     }
 
-#if defined(Q_QDOC)
+    explicit operator bool() const
-    inline operator bool() const
     {
-        return isNull() ? nullptr : &QScopedPointer::d;
+        return !isNull();
     }
-#else
-    operator RestrictedBool() const noexcept
-    {
-        return isNull() ? nullptr : &QScopedPointer::d;
-    }
-#endif
 
     T *data() const noexcept
     {

src/corelib/tools/qsharedpointer_impl.h

@@ -283,7 +283,6 @@ namespace QtSharedPointer {
 
 template <class T> class QSharedPointer
 {
-    typedef T *QSharedPointer:: *RestrictedBool;
     typedef QtSharedPointer::ExternalRefCountData Data;
     template <typename X>
     using IfCompatible = typename std::enable_if<std::is_convertible<X*, T*>::value, bool>::type;
@@ -301,7 +300,7 @@ public:
     T *data() const noexcept { return value; }
     T *get() const noexcept { return value; }
     bool isNull() const noexcept { return !data(); }
-    operator RestrictedBool() const noexcept { return isNull() ? nullptr : &QSharedPointer::value; }
+    explicit operator bool() const noexcept { return !isNull(); }
     bool operator !() const noexcept { return isNull(); }
     T &operator*() const { return *data(); }
     T *operator->() const noexcept { return data(); }
@@ -539,7 +538,6 @@ public:
 template <class T>
 class QWeakPointer
 {
-    typedef T *QWeakPointer:: *RestrictedBool;
     typedef QtSharedPointer::ExternalRefCountData Data;
     template <typename X>
     using IfCompatible = typename std::enable_if<std::is_convertible<X*, T*>::value, bool>::type;
@@ -554,7 +552,7 @@ public:
     typedef qptrdiff difference_type;
 
     bool isNull() const noexcept { return d == nullptr || d->strongref.loadRelaxed() == 0 || value == nullptr; }
-    operator RestrictedBool() const noexcept { return isNull() ? nullptr : &QWeakPointer::value; }
+    explicit operator bool() const noexcept { return !isNull(); }
     bool operator !() const noexcept { return isNull(); }
 
 #if QT_DEPRECATED_SINCE(5, 14)

src/opengl/qopengltextureblitter.cpp

@@ -440,7 +440,7 @@ bool QOpenGLTextureBlitter::create()
 bool QOpenGLTextureBlitter::isCreated() const
 {
     Q_D(const QOpenGLTextureBlitter);
-    return d->programs[QOpenGLTextureBlitterPrivate::TEXTURE_2D].glProgram;
+    return !d->programs[QOpenGLTextureBlitterPrivate::TEXTURE_2D].glProgram.isNull();
 }
 
 /*!

src/plugins/platforms/windows/qwindowsdialoghelpers.h

@@ -80,7 +80,7 @@ public:
 protected:
     QWindowsDialogHelperBase() = default;
     QWindowsNativeDialogBase *nativeDialog() const;
-    inline bool hasNativeDialog() const { return m_nativeDialog; }
+    inline bool hasNativeDialog() const { return !m_nativeDialog.isNull(); }
     void timerEvent(QTimerEvent *) override;
 
 private: