Remove qtypetraits.h's contents altogether

So that QFlags can use an (un)signed int matching the
underlying type as identified by the compiler and not by us.

Requires fixing a few warnings about sign conversion due to
QFlags misusages in qtbase that were either plain wrong, or
were relying on the enum being backed by an (un)signed int
when it wasn't.

Keep qtypetraits.h in the source tree in order to prevent
source breaks if some downstream #includes it (note however
that it did not contain any public API).

Change-Id: Ib3a92b98db7031e793a088fb2a3b306eff4d7a3c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

13 files changed, 44 insertions, 82 deletions

diff --git a/src/corelib/global/qflags.h b/src/corelib/global/qflags.h
index b871c90c9d..89a0ae9083 100644
--- a/src/corelib/global/qflags.h
+++ b/src/corelib/global/qflags.h
@@ -42,13 +42,12 @@
 #ifndef QFLAGS_H
 #define QFLAGS_H
 
-#include <QtCore/qtypeinfo.h>
-#include <QtCore/qtypetraits.h>
-
 #ifdef Q_COMPILER_INITIALIZER_LISTS
 #include <initializer_list>
 #endif
 
+#include <type_traits>
+
 QT_BEGIN_NAMESPACE
 
 class QFlag
@@ -94,6 +93,8 @@ class QFlags
     Q_STATIC_ASSERT_X((sizeof(Enum) <= sizeof(int)),
                       "QFlags uses an int as storage, so an enum with underlying "
                       "long long will overflow.");
+    Q_STATIC_ASSERT_X((std::is_enum<Enum>::value), "QFlags is only usable on enumeration types.");
+
     struct Private;
     typedef int (Private::*Zero);
 public:
@@ -103,7 +104,7 @@ public:
     typedef int Int;
 #else
     typedef typename std::conditional<
-            QtPrivate::QIsUnsignedEnum<Enum>::value,
+            std::is_unsigned<typename std::underlying_type<Enum>::type>::value,
             unsigned int,
             signed int
         >::type Int;
diff --git a/src/corelib/global/qtypetraits.h b/src/corelib/global/qtypetraits.h
index 9773db919b..35e407e2de 100644
--- a/src/corelib/global/qtypetraits.h
+++ b/src/corelib/global/qtypetraits.h
@@ -37,6 +37,12 @@
 **
 ****************************************************************************/
 
+// ### Qt 6: remove this header
+//
+// This header is deliberately empty. Although it did not contain any public API,
+// it was accidentally made public in Qt 5. So: do not remove it for the moment
+// being, to prevent #include breaks in downstreams.
+
 #include "QtCore/qglobal.h"
 
 #ifndef QTYPETRAITS_H
@@ -44,53 +50,6 @@
 
 QT_BEGIN_NAMESPACE
 
-namespace QtPrivate {
-
-//
-// Define QIsUnsignedEnum, QIsSignedEnum -
-// std::is_signed, std::is_unsigned does not work for enum's
-//
-
-// a metafunction to invert an integral_constant:
-template <typename T>
-struct not_
-    : std::integral_constant<bool, !T::value> {};
-
-// Checks whether a type is unsigned (T must be convertible to unsigned int):
-template <typename T>
-struct QIsUnsignedEnum
-    : std::integral_constant<bool, (T(0) < T(-1))> {};
-
-// Checks whether a type is signed (T must be convertible to int):
-template <typename T>
-struct QIsSignedEnum
-    : not_< QIsUnsignedEnum<T> > {};
-
-Q_STATIC_ASSERT(( QIsUnsignedEnum<quint8>::value));
-Q_STATIC_ASSERT((!QIsUnsignedEnum<qint8>::value));
-
-Q_STATIC_ASSERT((!QIsSignedEnum<quint8>::value));
-Q_STATIC_ASSERT(( QIsSignedEnum<qint8>::value));
-
-Q_STATIC_ASSERT(( QIsUnsignedEnum<quint16>::value));
-Q_STATIC_ASSERT((!QIsUnsignedEnum<qint16>::value));
-
-Q_STATIC_ASSERT((!QIsSignedEnum<quint16>::value));
-Q_STATIC_ASSERT(( QIsSignedEnum<qint16>::value));
-
-Q_STATIC_ASSERT(( QIsUnsignedEnum<quint32>::value));
-Q_STATIC_ASSERT((!QIsUnsignedEnum<qint32>::value));
-
-Q_STATIC_ASSERT((!QIsSignedEnum<quint32>::value));
-Q_STATIC_ASSERT(( QIsSignedEnum<qint32>::value));
-
-Q_STATIC_ASSERT(( QIsUnsignedEnum<quint64>::value));
-Q_STATIC_ASSERT((!QIsUnsignedEnum<qint64>::value));
-
-Q_STATIC_ASSERT((!QIsSignedEnum<quint64>::value));
-Q_STATIC_ASSERT(( QIsSignedEnum<qint64>::value));
-
-} // namespace QtPrivate
-
 QT_END_NAMESPACE
+
 #endif  // QTYPETRAITS_H
diff --git a/src/corelib/io/qurl.h b/src/corelib/io/qurl.h
index a554a3b07e..c16825a033 100644
--- a/src/corelib/io/qurl.h
+++ b/src/corelib/io/qurl.h
@@ -69,8 +69,8 @@ public:
     Q_DECL_CONSTEXPR inline QUrlTwoFlags(E1 f) : i(f) {}
     Q_DECL_CONSTEXPR inline QUrlTwoFlags(E2 f) : i(f) {}
     Q_DECL_CONSTEXPR inline QUrlTwoFlags(QFlag f) : i(f) {}
-    Q_DECL_CONSTEXPR inline QUrlTwoFlags(QFlags<E1> f) : i(f.operator int()) {}
-    Q_DECL_CONSTEXPR inline QUrlTwoFlags(QFlags<E2> f) : i(f.operator int()) {}
+    Q_DECL_CONSTEXPR inline QUrlTwoFlags(QFlags<E1> f) : i(f.operator typename QFlags<E1>::Int()) {}
+    Q_DECL_CONSTEXPR inline QUrlTwoFlags(QFlags<E2> f) : i(f.operator typename QFlags<E2>::Int()) {}
     Q_DECL_CONSTEXPR inline QUrlTwoFlags(Zero = 0) : i(0) {}
 
     inline QUrlTwoFlags &operator&=(int mask) { i &= mask; return *this; }
diff --git a/src/corelib/itemmodels/qabstractitemmodel.cpp b/src/corelib/itemmodels/qabstractitemmodel.cpp
index 7fdf107383..3faa8e1441 100644
--- a/src/corelib/itemmodels/qabstractitemmodel.cpp
+++ b/src/corelib/itemmodels/qabstractitemmodel.cpp
@@ -2044,7 +2044,7 @@ Qt::DropActions QAbstractItemModel::supportedDropActions() const
 Qt::DropActions QAbstractItemModel::supportedDragActions() const
 {
     Q_D(const QAbstractItemModel);
-    if (d->supportedDragActions != -1)
+    if (d->supportedDragActions != Qt::IgnoreAction)
         return d->supportedDragActions;
     return supportedDropActions();
 }
diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index f27fde6b8d..fb86d0222e 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -1027,7 +1027,7 @@ int QMetaType::registerNormalizedType(const NS(QByteArray) &normalizedTypeName,
                                   normalizedTypeName.size());
 
     int previousSize = 0;
-    int previousFlags = 0;
+    QMetaType::TypeFlags::Int previousFlags = 0;
     if (idx == UnknownType) {
         QWriteLocker locker(customTypesLock());
         int posInVector = -1;
diff --git a/src/corelib/kernel/qmetatype_p.h b/src/corelib/kernel/qmetatype_p.h
index dd0bce2645..6f1334d082 100644
--- a/src/corelib/kernel/qmetatype_p.h
+++ b/src/corelib/kernel/qmetatype_p.h
@@ -129,7 +129,7 @@ public:
     QMetaType::Constructor constructor;
     QMetaType::Destructor destructor;
     int size;
-    quint32 flags; // same as QMetaType::TypeFlags
+    QMetaType::TypeFlags::Int flags;
     const QMetaObject *metaObject;
 };
 
diff --git a/src/gui/opengl/qopengltexturecache.cpp b/src/gui/opengl/qopengltexturecache.cpp
index 688226551d..27aa8db33a 100644
--- a/src/gui/opengl/qopengltexturecache.cpp
+++ b/src/gui/opengl/qopengltexturecache.cpp
@@ -371,7 +371,7 @@ static void freeTexture(QOpenGLFunctions *funcs, GLuint id)
     funcs->glDeleteTextures(1, &id);
 }
 
-QOpenGLCachedTexture::QOpenGLCachedTexture(GLuint id, int options, QOpenGLContext *context) : m_options(options)
+QOpenGLCachedTexture::QOpenGLCachedTexture(GLuint id, QOpenGLTextureCache::BindOptions options, QOpenGLContext *context) : m_options(options)
 {
     m_resource = new QOpenGLSharedResourceGuard(context, id, freeTexture);
 }
diff --git a/src/gui/opengl/qopengltexturecache_p.h b/src/gui/opengl/qopengltexturecache_p.h
index c68b068739..4a438c8d95 100644
--- a/src/gui/opengl/qopengltexturecache_p.h
+++ b/src/gui/opengl/qopengltexturecache_p.h
@@ -60,19 +60,7 @@
 
 QT_BEGIN_NAMESPACE
 
-class QOpenGLCachedTexture
-{
-public:
-    QOpenGLCachedTexture(GLuint id, int options, QOpenGLContext *context);
-    ~QOpenGLCachedTexture() { m_resource->free(); }
-
-    GLuint id() const { return m_resource->id(); }
-    int options() const { return m_options; }
-
-private:
-    QOpenGLSharedResourceGuard *m_resource;
-    int m_options;
-};
+class QOpenGLCachedTexture;
 
 class Q_GUI_EXPORT QOpenGLTextureCache : public QOpenGLSharedResource
 {
@@ -106,6 +94,20 @@ private:
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QOpenGLTextureCache::BindOptions)
 
+class QOpenGLCachedTexture
+{
+public:
+    QOpenGLCachedTexture(GLuint id, QOpenGLTextureCache::BindOptions options, QOpenGLContext *context);
+    ~QOpenGLCachedTexture() { m_resource->free(); }
+
+    GLuint id() const { return m_resource->id(); }
+    QOpenGLTextureCache::BindOptions options() const { return m_options; }
+
+private:
+    QOpenGLSharedResourceGuard *m_resource;
+    QOpenGLTextureCache::BindOptions m_options;
+};
+
 QT_END_NAMESPACE
 
 #endif
diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp
index 3e15b6977a..7295cc36f6 100644
--- a/src/widgets/kernel/qwidgetwindow.cpp
+++ b/src/widgets/kernel/qwidgetwindow.cpp
@@ -957,8 +957,8 @@ void QWidgetWindow::handleWindowStateChangedEvent(QWindowStateChangeEvent *event
 
     // Sent event if the state changed (that is, it is not triggered by
     // QWidget::setWindowState(), which also sends an event to the widget).
-    if (widgetState != int(m_widget->data->window_state)) {
-        m_widget->data->window_state = widgetState;
+    if (widgetState != Qt::WindowStates::Int(m_widget->data->window_state)) {
+        m_widget->data->window_state = uint(widgetState);
         QWindowStateChangeEvent widgetEvent(eventState);
         QGuiApplication::sendSpontaneousEvent(m_widget, &widgetEvent);
     }
diff --git a/src/widgets/styles/qfusionstyle.cpp b/src/widgets/styles/qfusionstyle.cpp
index 74e4d53dca..70af751fd3 100644
--- a/src/widgets/styles/qfusionstyle.cpp
+++ b/src/widgets/styles/qfusionstyle.cpp
@@ -2417,7 +2417,7 @@ void QFusionStyle::drawComplexControl(ComplexControl control, const QStyleOption
                 int oldMin = styleObject->property("_q_stylemin").toInt();
                 int oldMax = styleObject->property("_q_stylemax").toInt();
                 QRect oldRect = styleObject->property("_q_stylerect").toRect();
-                int oldState = styleObject->property("_q_stylestate").toInt();
+                QStyle::State oldState = static_cast<QStyle::State>(styleObject->property("_q_stylestate").value<QStyle::State::Int>());
                 uint oldActiveControls = styleObject->property("_q_stylecontrols").toUInt();
 
                 // a scrollbar is transient when the the scrollbar itself and
@@ -2440,7 +2440,7 @@ void QFusionStyle::drawComplexControl(ComplexControl control, const QStyleOption
                     styleObject->setProperty("_q_stylemin", scrollBar->minimum);
                     styleObject->setProperty("_q_stylemax", scrollBar->maximum);
                     styleObject->setProperty("_q_stylerect", scrollBar->rect);
-                    styleObject->setProperty("_q_stylestate", static_cast<int>(scrollBar->state));
+                    styleObject->setProperty("_q_stylestate", static_cast<QStyle::State::Int>(scrollBar->state));
                     styleObject->setProperty("_q_stylecontrols", static_cast<uint>(scrollBar->activeSubControls));
 
 #ifndef QT_NO_ANIMATION
diff --git a/src/widgets/styles/qmacstyle_mac.mm b/src/widgets/styles/qmacstyle_mac.mm
index 272877130b..ee257c7310 100644
--- a/src/widgets/styles/qmacstyle_mac.mm
+++ b/src/widgets/styles/qmacstyle_mac.mm
@@ -5284,7 +5284,7 @@ void QMacStyle::drawComplexControl(ComplexControl cc, const QStyleOptionComplex
                     int oldMin = styleObject->property("_q_stylemin").toInt();
                     int oldMax = styleObject->property("_q_stylemax").toInt();
                     QRect oldRect = styleObject->property("_q_stylerect").toRect();
-                    int oldState = styleObject->property("_q_stylestate").toInt();
+                    QStyle::State oldState = static_cast<QStyle::State>(styleObject->property("_q_stylestate").value<QStyle::State::Int>());
                     uint oldActiveControls = styleObject->property("_q_stylecontrols").toUInt();
 
                     // a scrollbar is transient when the scrollbar itself and
@@ -5307,7 +5307,7 @@ void QMacStyle::drawComplexControl(ComplexControl cc, const QStyleOptionComplex
                         styleObject->setProperty("_q_stylemin", slider->minimum);
                         styleObject->setProperty("_q_stylemax", slider->maximum);
                         styleObject->setProperty("_q_stylerect", slider->rect);
-                        styleObject->setProperty("_q_stylestate", static_cast<int>(slider->state));
+                        styleObject->setProperty("_q_stylestate", static_cast<QStyle::State::Int>(slider->state));
                         styleObject->setProperty("_q_stylecontrols", static_cast<uint>(slider->activeSubControls));
 
                         QScrollbarStyleAnimation *anim  = qobject_cast<QScrollbarStyleAnimation *>(d->animation(styleObject));
diff --git a/tests/auto/corelib/global/qflags/tst_qflags.cpp b/tests/auto/corelib/global/qflags/tst_qflags.cpp
index 634d9a2df3..d70b099fe3 100644
--- a/tests/auto/corelib/global/qflags/tst_qflags.cpp
+++ b/tests/auto/corelib/global/qflags/tst_qflags.cpp
@@ -134,11 +134,11 @@ void tst_QFlags::signedness()
     // underlying type is implementation-defined, we need to allow for
     // a different signedness, so we only check that the relative
     // signedness of the types matches:
-    Q_STATIC_ASSERT((QtPrivate::QIsUnsignedEnum<Qt::MouseButton>::value ==
-                     QtPrivate::QIsUnsignedEnum<Qt::MouseButtons::Int>::value));
+    Q_STATIC_ASSERT((std::is_unsigned<typename std::underlying_type<Qt::MouseButton>::type>::value ==
+                     std::is_unsigned<Qt::MouseButtons::Int>::value));
 
-    Q_STATIC_ASSERT((QtPrivate::QIsSignedEnum<Qt::AlignmentFlag>::value ==
-                     QtPrivate::QIsSignedEnum<Qt::Alignment::Int>::value));
+    Q_STATIC_ASSERT((std::is_signed<typename std::underlying_type<Qt::AlignmentFlag>::type>::value ==
+                     std::is_signed<Qt::Alignment::Int>::value));
 }
 
 #if defined(Q_COMPILER_CLASS_ENUM)
diff --git a/tests/auto/other/modeltest/modeltest.cpp b/tests/auto/other/modeltest/modeltest.cpp
index 3c74592528..4da00bda4d 100644
--- a/tests/auto/other/modeltest/modeltest.cpp
+++ b/tests/auto/other/modeltest/modeltest.cpp
@@ -438,7 +438,7 @@ void ModelTest::data()
     // Check that the alignment is one we know about
     QVariant textAlignmentVariant = model->data ( model->index ( 0, 0 ), Qt::TextAlignmentRole );
     if ( textAlignmentVariant.isValid() ) {
-        int alignment = textAlignmentVariant.toInt();
+        Qt::Alignment alignment = textAlignmentVariant.value<Qt::Alignment>();
         QCOMPARE( alignment, ( alignment & ( Qt::AlignHorizontal_Mask | Qt::AlignVertical_Mask ) ) );
     }