Merge remote-tracking branch 'origin/tqtc/lts-6.2.6' into tqtc/lts-6.2-opensource

Change-Id: Ie5a87ae61d8ed0429225353ad46e5232d60f4daa

44 files changed, 771 insertions, 438 deletions

diff --git a/src/qml/CMakeLists.txt b/src/qml/CMakeLists.txt
index 45a1b274e6..1cacf0d889 100644
--- a/src/qml/CMakeLists.txt
+++ b/src/qml/CMakeLists.txt
@@ -510,7 +510,7 @@ qt_internal_extend_target(Qml CONDITION QT_FEATURE_qml_debug
         debugger/qqmldebug.cpp
         debugger/qqmldebugconnector.cpp
         debugger/qqmldebugpluginmanager_p.h
-        debugger/qqmldebugserver_p.h
+        debugger/qqmldebugserver.cpp debugger/qqmldebugserver_p.h
         debugger/qqmldebugserverconnection_p.h
         debugger/qqmldebugservice.cpp debugger/qqmldebugservice_p.h
         debugger/qqmldebugservicefactory_p.h
diff --git a/src/qml/Qt6QmlMacros.cmake b/src/qml/Qt6QmlMacros.cmake
index 4f3cf714b9..d26f183f5d 100644
--- a/src/qml/Qt6QmlMacros.cmake
+++ b/src/qml/Qt6QmlMacros.cmake
@@ -2000,7 +2000,7 @@ but this file does not exist.  Possible reasons include:
 ")
     endif()
 
-    # Find QML import paths.
+    # Find Qt provided QML import paths.
     if("${_qt_additional_packages_prefix_paths}" STREQUAL "")
         # We have one installation prefix for all Qt modules. Add the "<prefix>/qml" directory.
         set(qml_import_paths "${QT6_INSTALL_PREFIX}/${QT6_INSTALL_QML}")
@@ -2008,7 +2008,9 @@ but this file does not exist.  Possible reasons include:
         # We have multiple installation prefixes: one per Qt repository (conan). Add those that have
         # a "qml" subdirectory.
         set(qml_import_paths)
-        foreach(root IN ITEMS "${QT6_INSTALL_PREFIX};${_qt_additional_packages_prefix_paths}")
+        __qt_internal_prefix_paths_to_roots(
+            additional_root_paths "${_qt_additional_packages_prefix_paths}")
+        foreach(root IN ITEMS ${QT6_INSTALL_PREFIX} ${additional_root_paths})
             set(candidate "${root}/${QT6_INSTALL_QML}")
             if(IS_DIRECTORY "${candidate}")
                 list(APPEND qml_import_paths "${candidate}")
@@ -2016,11 +2018,6 @@ but this file does not exist.  Possible reasons include:
         endforeach()
     endif()
 
-    # Construct the -importPath arguments.
-    set(import_path_arguments)
-    foreach(path IN LISTS qml_import_paths)
-        list(APPEND import_path_arguments -importPath ${path})
-    endforeach()
 
     # Small macro to avoid duplicating code in two different loops.
     macro(_qt6_QmlImportScanner_parse_entry)
@@ -2044,7 +2041,6 @@ but this file does not exist.  Possible reasons include:
     set(cmd_args
         -rootPath "${arg_PATH_TO_SCAN}"
         -cmake-output
-        ${import_path_arguments}
     )
     get_target_property(qml_import_path ${target} QT_QML_IMPORT_PATH)
 
@@ -2055,18 +2051,26 @@ but this file does not exist.  Possible reasons include:
     # Facilitate self-import so we can find the qmldir file
     get_target_property(module_out_dir ${target} QT_QML_MODULE_OUTPUT_DIRECTORY)
     if(module_out_dir)
-        list(APPEND cmd_args "${module_out_dir}")
+        list(APPEND qml_import_paths "${module_out_dir}")
     endif()
 
     # Find qmldir files we copied to the build directory
     if(NOT "${QT_QML_OUTPUT_DIRECTORY}" STREQUAL "")
         if(EXISTS "${QT_QML_OUTPUT_DIRECTORY}")
-            list(APPEND cmd_args "${QT_QML_OUTPUT_DIRECTORY}")
+            list(APPEND qml_import_paths "${QT_QML_OUTPUT_DIRECTORY}")
         endif()
     else()
-        list(APPEND cmd_args "${CMAKE_CURRENT_BINARY_DIR}")
+        list(APPEND qml_import_paths "${CMAKE_CURRENT_BINARY_DIR}")
     endif()
 
+    # Construct the -importPath arguments.
+    set(import_path_arguments)
+    foreach(path IN LISTS qml_import_paths)
+        list(APPEND import_path_arguments -importPath ${path})
+    endforeach()
+
+    list(APPEND cmd_args ${import_path_arguments})
+
     # All of the module's .qml files will be listed in one of the generated
     # .qrc files, so there's no need to list the files individually. We provide
     # the .qrc files instead because they have the additional information for
diff --git a/src/qml/common/qv4compileddata_p.h b/src/qml/common/qv4compileddata_p.h
index f4c41f69f8..3f33743ecf 100644
--- a/src/qml/common/qv4compileddata_p.h
+++ b/src/qml/common/qv4compileddata_p.h
@@ -129,7 +129,7 @@ struct TableIterator
 struct Location
 {
     Location() : m_data(QSpecialIntegerBitfieldZero) {}
-    Location(quint32 l, quint32 c)
+    Location(quint32 l, quint32 c) : Location()
     {
         m_data.set<LineField>(l);
         m_data.set<ColumnField>(c);
@@ -182,7 +182,7 @@ struct RegExp
     };
 
     RegExp() : m_data(QSpecialIntegerBitfieldZero) {}
-    RegExp(quint32 flags, quint32 stringIndex)
+    RegExp(quint32 flags, quint32 stringIndex) : RegExp()
     {
         m_data.set<FlagsField>(flags);
         m_data.set<StringIndexField>(stringIndex);
@@ -211,7 +211,7 @@ struct Lookup
     quint32 nameIndex() const { return m_data.get<NameIndexField>(); }
 
     Lookup() : m_data(QSpecialIntegerBitfieldZero) {}
-    Lookup(Type type, quint32 nameIndex)
+    Lookup(Type type, quint32 nameIndex) : Lookup()
     {
         m_data.set<TypeAndFlagsField>(type);
         m_data.set<NameIndexField>(nameIndex);
diff --git a/src/qml/debugger/qqmldebugconnector_p.h b/src/qml/debugger/qqmldebugconnector_p.h
index d1ad90adfd..4f7b013160 100644
--- a/src/qml/debugger/qqmldebugconnector_p.h
+++ b/src/qml/debugger/qqmldebugconnector_p.h
@@ -65,6 +65,7 @@ QT_BEGIN_NAMESPACE
 
 class Q_QML_PRIVATE_EXPORT QQmlDebugConnector
 {
+    virtual ~QQmlDebugConnector() = default; // don't break 'override' on ~QQmlDebugServer
 public:
     static QQmlDebugConnector *instance() { return nullptr; }
 
diff --git a/src/qml/debugger/qqmldebugserver.cpp b/src/qml/debugger/qqmldebugserver.cpp
new file mode 100644
index 0000000000..5119fc4209
--- /dev/null
+++ b/src/qml/debugger/qqmldebugserver.cpp
@@ -0,0 +1,49 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qqmldebugserver_p.h"
+
+QT_BEGIN_NAMESPACE
+
+QQmlDebugServer::~QQmlDebugServer()
+    = default;
+
+QT_END_NAMESPACE
+
+#include "moc_qqmldebugserver_p.cpp"
diff --git a/src/qml/debugger/qqmldebugserver_p.h b/src/qml/debugger/qqmldebugserver_p.h
index e848b00bda..c99155051c 100644
--- a/src/qml/debugger/qqmldebugserver_p.h
+++ b/src/qml/debugger/qqmldebugserver_p.h
@@ -62,6 +62,7 @@ class Q_QML_PRIVATE_EXPORT QQmlDebugServer : public QQmlDebugConnector
 {
     Q_OBJECT
 public:
+    ~QQmlDebugServer() override;
     virtual void setDevice(QIODevice *socket) = 0;
 };
 
diff --git a/src/qml/doc/src/cmake/qt_add_qml_module.qdoc b/src/qml/doc/src/cmake/qt_add_qml_module.qdoc
index 810f45b127..a66aa27561 100644
--- a/src/qml/doc/src/cmake/qt_add_qml_module.qdoc
+++ b/src/qml/doc/src/cmake/qt_add_qml_module.qdoc
@@ -73,6 +73,9 @@ qt_add_qml_module(
 
 \versionlessCMakeCommandsNote qt6_add_qml_module()
 
+See \l {Building a QML application} and \l {Building a reusable QML module}
+for examples that define QML modules.
+
 \section1 Description
 
 This command defines a QML module that can consist of C++ sources, \c{.qml}
@@ -126,6 +129,10 @@ For cases where the QML module needs a custom plugin class implementation, the
 \l{NO_GENERATE_PLUGIN_SOURCE} and usually the \l{NO_PLUGIN_OPTIONAL} options
 will be needed.
 
+\note
+When using static linking, it migt be necessary to use
+\c Q_IMPORT_QML_PLUGIN to ensure that the QML plugin is correctly linked.
+
 \section3 Plugin target with no backing target
 
 A QML module can be defined with the plugin target serving as its own backing
diff --git a/src/qml/doc/src/cppintegration/definetypes.qdoc b/src/qml/doc/src/cppintegration/definetypes.qdoc
index d5c1d3e0c9..40e0627e6d 100644
--- a/src/qml/doc/src/cppintegration/definetypes.qdoc
+++ b/src/qml/doc/src/cppintegration/definetypes.qdoc
@@ -334,10 +334,9 @@ classes directly, if this is either not possible or is complicated by some
 other concerns, extension objects allow limited extension possibilities
 without direct modifications.
 
-\e{Extension objects} add additional properties to an existing type. Extension
-objects can only add properties, not signals or methods. An extended type
-definition allows the programmer to supply an additional type, known as the
-\e{extension type}, when registering the class. The properties are transparently
+\e{Extension objects} add additional properties to an existing type. An extended
+type definition allows the programmer to supply an additional type, known as the
+\e{extension type}, when registering the class. Its members are transparently
 merged with the original target class when used from within QML. For example:
 
 \snippet referenceexamples/extended/example.qml 0
diff --git a/src/qml/doc/src/javascript/hostenvironment.qdoc b/src/qml/doc/src/javascript/hostenvironment.qdoc
index 99aa4cd058..943da5cbef 100644
--- a/src/qml/doc/src/javascript/hostenvironment.qdoc
+++ b/src/qml/doc/src/javascript/hostenvironment.qdoc
@@ -42,7 +42,8 @@ Like a browser or server-side JavaScript environment, the QML runtime implements
 all of the built-in types and functions defined by the standard, such as Object, Array, and Math.
 The QML runtime implements the 7th edition of the standard.
 
-\l{Nullish Coalescing} (since Qt 5.15) and \l{Optional Chaining} (since Qt 6.2) are also implemented in the QML runtime.
+\l{Nullish Coalescing} (\c{??}) (since Qt 5.15) and \l{Optional Chaining} (\c{?.}) (since Qt 6.2)
+are also implemented in the QML runtime.
 
 The standard ECMAScript built-ins are not explicitly documented in the QML documentation. For more
 information on their use, please refer to the ECMA-262 7th edition standard or one of the many online
diff --git a/src/qml/doc/src/qmllanguageref/documents/definetypes.qdoc b/src/qml/doc/src/qmllanguageref/documents/definetypes.qdoc
index 718b0c25ac..562b262271 100644
--- a/src/qml/doc/src/qmllanguageref/documents/definetypes.qdoc
+++ b/src/qml/doc/src/qmllanguageref/documents/definetypes.qdoc
@@ -53,8 +53,12 @@ The type name has the following requirements:
 
 This document is then automatically recognized by the engine as a definition of
 a QML type. Additionally, a type defined in this manner is automatically made
-available to other QML files within the same directory as the engine searches
-within the immediate directory when resolving QML type names.
+available to other QML files within the same local directory as the engine
+searches within the immediate directory when resolving QML type names.
+
+\note The QML engine does not automatically search remote directories this way.
+You have to add a qmldir file if your documents are loaded over the network. See
+\l{Importing QML Document Directories}.
 
 \section2 Custom QML Type Definition
 
diff --git a/src/qml/doc/src/qmllanguageref/modules/qmldir.qdoc b/src/qml/doc/src/qmllanguageref/modules/qmldir.qdoc
index 95e8a179de..be1908f7cd 100644
--- a/src/qml/doc/src/qmllanguageref/modules/qmldir.qdoc
+++ b/src/qml/doc/src/qmllanguageref/modules/qmldir.qdoc
@@ -43,278 +43,287 @@ module. For more information about the first form of \c qmldir file, see
 
 \section1 Contents of a Module Definition qmldir File
 
-A \c qmldir file is a plain-text file that contains
-the following commands:
-
-\table 70%
-    \header
-        \li Syntax
-        \li Usage
-    \row
-        \li
-            \code
-module <ModuleIdentifier>
-            \endcode
-        \li Declares the module identifier of the module.
-            The <ModuleIdentifier> is the (dotted URI notation) identifier
-            for the module, which must match the module's install path.
-
-            The \l{Identified Modules#Semantics of Identified Modules}
-            {module identifier directive} must be the first line of the file.
-            Exactly one module identifier directive may exist in the \c qmldir
-            file.
-
-            Example:
-            \code
-module ExampleModule
-            \endcode
-
-    \row
-        \li
-            \code
-[singleton] <TypeName> <InitialVersion> <File>
-            \endcode
-        \li Declares a \l{qtqml-typesystem-objecttypes.html}{QML object type}
-            to be made available by the module.
-                \list
-                \li \c [singleton] Optional. Used to declare a singleton type.
-                \li \c <TypeName> is the type being made available
-                \li \c <InitialVersion> is the module version for which the type is to be made available
-                \li \c <File> is the (relative) file name of the QML file that defines the type
-                \endlist
-
-            Zero or more object type declarations may exist in the \c qmldir
-            file, however each object type must have a unique type name within
-            any particular version of the module.
-            \note To declare a \c singleton type, the QML file defining the
-            type must include the \c {pragma Singleton} statement.
-
-            Example:
-            \code
-//Style.qml with custom singleton type definition
-pragma Singleton
-import QtQuick 2.0
+A \c qmldir file is a plain-text file that contains the following commands:
 
-QtObject {
-    property int textSize: 20
-    property color textColor: "green"
-}
+\list
+    \li \l {Module Identifier Declaration}
+    \li \l {Object Type Declaration}
+    \li \l {Internal Object Type Declaration}
+    \li \l {JavaScript Resource Declaration}
+    \li \l {Plugin Declaration}
+    \li \l {Plugin Classname Declaration}
+    \li \l {Type Description File Declaration}
+    \li \l {Module Dependencies Declaration}
+    \li \l {Module Import Declaration}
+    \li \l {Designer Support Declaration}
+    \li \l {Preferred Path Declaration}
+\endlist
 
-// qmldir declaring the singleton type
-module CustomStyles
-singleton Style 1.0 Style.qml
+\note Each command in a \c qmldir file must be on a separate line.
 
-// singleton type in use
-import QtQuick 2.0
-import CustomStyles 1.0
+In addition to commands, you can also add comments, which are lines starting
+with \c {#}.
 
-Text {
-    font.pixelSize: Style.textSize
-    color: Style.textColor
-    text: "Hello World"
-}
-            \endcode
-
-    \row
-        \li
-            \code
-internal <TypeName> <File>
-            \endcode
-        \li Declares an object type that is in the module but should not be
-            made available to users of the module.
-
-            Zero or more internal object type declarations may exist in the
-            \c qmldir file.
-
-            Example:
-            \code
-internal MyPrivateType MyPrivateType.qml
-         \endcode
-
-            This is necessary if the module may be imported remotely (see
-            \l{Identified Modules#Remotely Installed Identified Modules}
-            {Remotely Installed Identified Modules}) because if an exported type depends
-            on an non-exported type within the module, the engine must also
-            load the non-exported type.
-
-    \row
-        \li
-            \code
-<ResourceIdentifier> <InitialVersion> <File>
-            \endcode
-        \li Declares a JavaScript file to be made available by the module.
-            The resource will be made available via the specified identifier
-            with the specified version number.
-
-            Zero or more JavaScript resource declarations may exist in the
-            \c qmldir file, however each JavaScript resource must have a unique
-            identifier within any particular version of the module.
-
-            Example:
-            \code
-MyScript 1.0 MyScript.js
-            \endcode
-
-            See the documentation about \l{qtqml-javascript-resources.html}
-            {defining JavaScript resources} and
-            \l{qtqml-javascript-imports.html}
-            {Importing JavaScript Resources In QML} for more information.
-
-    \row
-        \li
-            \code
-[optional] plugin <Name> [<Path>]
-            \endcode
-        \li Declares a plugin to be made available by the module.
-
-            \list
-            \li \c optional denotes that the plugin itself does not contain
-                any relevant code and only serves to load a library it links
-                to. If given, and if any types for the module are already
-                available, indicating that the library has been loaded by some
-                other means, QML will not load the plugin.
-            \li \c <Name> is the plugin library name. This is usually not the
-                same as the file name of the plugin binary, which is platform
-                dependent; e.g. the library \c MyAppTypes would produce
-                \c libMyAppTypes.so on Linux and \c MyAppTypes.dll on Windows.
-            \li \c <Path> (optional) specifies either:
-                \list
-                \li an absolute path to the directory containing the plugin
-                    file, or
-                \li a relative path from the directory containing the \c qmldir
-                    file to the directory containing the plugin file.
-                \endlist
-
-                By default the engine searches for the plugin library in the
-                directory that contains the \c qmldir file. (The plugin search
-                path can be queried with QQmlEngine::pluginPathList() and
-                modified using QQmlEngine::addPluginPath().)
-            \endlist
-
-            Zero or more C++ plugin declarations may exist in the \c qmldir
-            file, however since plugin loading is a relatively expensive
-            operation, clients are advised to specify at most a single plugin.
-
-            Example:
-            \code
-plugin MyPluginLibrary
-           \endcode
-    \row
-        \li
-            \code
-classname <C++ plugin class>
-            \endcode
-        \li Provides the class name of the C++ plugin used by the module.
-
-            This information is required for all the QML modules that depend
-            on a C++ plugin for additional functionality. Qt Quick applications
-            built with static linking cannot resolve the module imports without
-            this information.
-
-    \row
-        \li
-            \code
-typeinfo <File>
-            \endcode
-        \li Declares a \l{Type Description Files}{type description file} for
-            the module that can be read by QML tools such as Qt Creator to
-            access information about the types defined by the module's plugins.
-            \c <File> is the (relative) file name of a \c .qmltypes file.
-
-            Example:
-            \code
-typeinfo mymodule.qmltypes
-            \endcode
-
-            Without such a file, QML tools may be unable to offer features such
-            as code completion for the types defined in your plugins.
-
-    \row
-        \li
-            \code
-depends <ModuleIdentifier> <InitialVersion>
-            \endcode
-        \li Declares that this module depends on another.
-
-            Example:
-            \code
-depends MyOtherModule 1.0
-            \endcode
-
-            This declaration is necessary only in cases when the dependency is
-            hidden: for example, when the C++ code for one module is used to
-            load QML (perhaps conditionally) which then depends on other
-            modules. In such cases, the \c depends declaration is necessary
-            to include the other modules in application packages.
-    \row
-        \li
-            \code
-import <ModuleIdentifier> [<Version>]
-            \endcode
-        \li Declares that this module imports another.
-
-            Example:
-            \code
-import MyOtherModule 1.0
-            \endcode
-
-            The types from the other module are made available in the same type
-            namespace as this module is imported into. Omitting the version
-            imports the latest version available of the other module, specifying
-            \c auto as version imports the same version as the version of this
-            module specified in the QML \c import statement.
-
-    \row
-        \li
-            \code
-# <Comment>
-            \endcode
-        \li Declares a comment. These are ignored by the engine.
-
-            Example:
-            \code
-# this is a comment
-            \endcode
-
-    \row
-    \li
-         \code
-designersupported
-         \endcode
-
-     \li Set this property if the plugin is supported by Qt Quick Designer.
-         By default, the plugin will not be supported.
-
-         A plugin that is supported by Qt Quick Designer has to be properly
-         tested. This means that the plugin does not crash when running inside
-         the qml2puppet that is used by Qt Quick Designer to execute QML.
-         Generally the plugin should work well in the Qt Quick Designer
-         and not cause any show stoppers, like taking huge amounts of memory,
-         slowing down the qml2puppet heavily or anything else that renders
-         the plugin effectively unusable in the Qt Quick Designer.
-
-         The items of an unsupported plugin are not painted in the Qt Quick Designer,
-         but they are still available as empty boxes and the properties can be edited.
-
-    \row
-    \li
-        \code
-prefer <Path>
-        \endcode
-
-    \li This property directs the QML engine to load any further files for this
-        module from <path>, rather than the current directory. This can be used
-        to load files compiled with qmlcachegen.
-
-        For example, you can add a module's QML files as resources to a resource
-        path \c{:/my/path/MyModule/}. Then, add \c{prefer :/my/path/MyModule} to
-        the qmldir file in order to use the files in the resource system, rather
-        than the ones in the file system. If you then use qmlcachegen for those,
-        the pre-compiled files will be available to any clients of the module.
-
-\endtable
-
-Each command in a \c qmldir file must be on a separate line.
+\section2 Module Identifier Declaration
+
+\code
+    module <ModuleIdentifier>
+\endcode
+
+Declares the module identifier of the module. The <ModuleIdentifier> is the
+(dotted URI notation) identifier for the module, which must match the module's
+install path.
+
+The \l{Identified Modules#Semantics of Identified Modules}
+{module identifier directive} must be the first line of the file. Exactly one
+module identifier directive may exist in the \c qmldir file.
+
+Example:
+\code
+    module ExampleModule
+\endcode
+
+\section2 Object Type Declaration
+\code
+    [singleton] <TypeName> <InitialVersion> <File>
+\endcode
+
+Declares a \l{qtqml-typesystem-objecttypes.html}{QML object type}
+to be made available by the module.
+\list
+    \li \c [singleton] Optional. Used to declare a singleton type.
+    \li \c <TypeName> is the type being made available
+    \li \c <InitialVersion> is the module version for which the type is to be
+    made available
+    \li \c <File> is the (relative) file name of the QML file that defines
+    the type
+\endlist
+
+Zero or more object type declarations may exist in the \c qmldir
+file. However, each object type must have a unique type name within
+any particular version of the module.
+\note To declare a \c singleton type, the QML file defining the
+type must include the \c {pragma Singleton} statement.
+
+Example:
+\code
+    //Style.qml with custom singleton type definition
+    pragma Singleton
+    import QtQuick 2.0
+
+    QtObject {
+        property int textSize: 20
+        property color textColor: "green"
+    }
+
+    // qmldir declaring the singleton type
+    module CustomStyles
+    singleton Style 1.0 Style.qml
+
+    // singleton type in use
+    import QtQuick 2.0
+    import CustomStyles 1.0
+
+    Text {
+        font.pixelSize: Style.textSize
+        color: Style.textColor
+        text: "Hello World"
+    }
+\endcode
+
+\section2 Internal Object Type Declaration
+
+\code
+    internal <TypeName> <File>
+\endcode
+
+Declares an object type that is in the module but should not be
+made available to users of the module.
+
+Zero or more internal object type declarations may exist in the
+\c qmldir file.
+
+Example:
+\code
+    internal MyPrivateType MyPrivateType.qml
+\endcode
+
+This is necessary if the module is imported remotely
+(see \l{Identified Modules#Remotely Installed Identified Modules}
+{Remotely Installed Identified Modules}) because if an exported type depends
+on a non-exported type within the module, the engine must also
+load the non-exported type.
+
+\section2 JavaScript Resource Declaration
+
+\code
+    <ResourceIdentifier> <InitialVersion> <File>
+\endcode
+
+Declares a JavaScript file to be made available by the module.
+The resource will be made available via the specified identifier
+with the specified version number.
+
+Zero or more JavaScript resource declarations may exist in the
+\c qmldir file. However, each JavaScript resource must have a unique
+identifier within any particular version of the module.
+
+Example:
+\code
+    MyScript 1.0 MyScript.js
+\endcode
+
+See the documentation about \l{qtqml-javascript-resources.html}
+{defining JavaScript resources} and
+\l{qtqml-javascript-imports.html}
+{Importing JavaScript Resources In QML} for more information.
+
+\section2 Plugin Declaration
+
+\code
+    [optional] plugin <Name> [<Path>]
+\endcode
+
+Declares a plugin to be made available by the module.
+
+\list
+    \li \c optional denotes that the plugin itself does not contain
+        any relevant code and only serves to load a library it links
+        to. If given, and if any types for the module are already
+        available, indicating that the library has been loaded by some
+        other means, QML will not load the plugin.
+    \li \c <Name> is the plugin library name. This is usually not the
+        same as the file name of the plugin binary, which is platform
+        dependent. For example, the library \c MyAppTypes would produce
+        \c libMyAppTypes.so on Linux and \c MyAppTypes.dll on Windows.
+    \li \c <Path> (optional) specifies either:
+        \list
+            \li an absolute path to the directory containing the plugin
+            file, or
+            \li a relative path from the directory containing the \c qmldir
+            file to the directory containing the plugin file.
+        \endlist
+\endlist
+
+By default, the engine searches for the plugin library in the
+directory that contains the \c qmldir file. (The plugin search
+path can be queried with QQmlEngine::pluginPathList() and
+modified using QQmlEngine::addPluginPath().)
+
+Zero or more C++ plugin declarations may exist in the \c qmldir
+file. However, since plugin loading is a relatively expensive
+operation, clients are advised to specify at most a single plugin.
+
+Example:
+\code
+    plugin MyPluginLibrary
+\endcode
+
+\section2 Plugin Classname Declaration
+
+\code
+    classname <C++ plugin class>
+\endcode
+
+Provides the class name of the C++ plugin used by the module.
+
+This information is required for all the QML modules that depend
+on a C++ plugin for additional functionality. Qt Quick applications
+built with static linking cannot resolve the module imports without
+this information.
+
+\section2 Type Description File Declaration
+
+\code
+    typeinfo <File>
+\endcode
+
+Declares a \l{Type Description Files}{type description file} for
+the module that can be read by QML tools such as Qt Creator to
+access information about the types defined by the module's plugins.
+\c <File> is the (relative) file name of a \c .qmltypes file.
+
+Example:
+\code
+    typeinfo mymodule.qmltypes
+\endcode
+
+Without such a file, QML tools may be unable to offer features such
+as code completion for the types defined in your plugins.
+
+\section2 Module Dependencies Declaration
+
+\code
+    depends <ModuleIdentifier> <InitialVersion>
+\endcode
+
+Declares that this module depends on another.
+
+Example:
+\code
+    depends MyOtherModule 1.0
+\endcode
+
+This declaration is necessary only in cases when the dependency is
+hidden: for example, when the C++ code for one module is used to
+load QML (perhaps conditionally), which then depends on other
+modules. In such cases, the \c depends declaration is necessary
+to include the other modules in application packages.
+
+\section2 Module Import Declaration
+
+\code
+    import <ModuleIdentifier> [<Version>]
+\endcode
+
+Declares that this module imports another.
+
+Example:
+\code
+    import MyOtherModule 1.0
+\endcode
+
+The types from the other module are made available in the same type
+namespace as this module is imported into. Omitting the version
+imports the latest version available of the other module. Specifying
+\c auto as version imports the same version as the version of this
+module specified in the QML \c import statement.
+
+\section2 Designer Support Declaration
+
+\code
+    designersupported
+\endcode
+
+Set this property if the plugin is supported by Qt Quick Designer.
+By default, the plugin will not be supported.
+
+A plugin that is supported by Qt Quick Designer has to be properly
+tested. This means that the plugin does not crash when running inside
+the qml2puppet that is used by Qt Quick Designer to execute QML.
+Generally, the plugin should work well in the Qt Quick Designer
+and not cause any show stoppers, like taking excessive amounts of memory,
+slowing down the qml2puppet heavily, or anything else that renders
+the plugin effectively unusable in the Qt Quick Designer.
+
+The items of an unsupported plugin are not painted in the Qt Quick Designer,
+but they are still available as empty boxes and the properties can be edited.
+
+\section2 Preferred Path Declaration
+
+\code
+    prefer <Path>
+\endcode
+
+This property directs the QML engine to load any further files for this
+module from <path>, rather than the current directory. This can be used
+to load files compiled with qmlcachegen.
+
+For example, you can add a module's QML files as resources to a resource
+path \c{:/my/path/MyModule/}. Then, add \c{prefer :/my/path/MyModule} to
+the qmldir file in order to use the files in the resource system, rather
+than the ones in the file system. If you then use qmlcachegen for those,
+the pre-compiled files will be available to any clients of the module.
 
 \section1 Versioning Semantics
 
diff --git a/src/qml/doc/src/qmllanguageref/modules/qqmlextensionplugin.qdocinc b/src/qml/doc/src/qmllanguageref/modules/qqmlextensionplugin.qdocinc
index b1fce12dc3..834977994f 100644
--- a/src/qml/doc/src/qmllanguageref/modules/qqmlextensionplugin.qdocinc
+++ b/src/qml/doc/src/qmllanguageref/modules/qqmlextensionplugin.qdocinc
@@ -26,6 +26,14 @@ plugins. Library plugins should limit themselves to registering types, as
 any manipulation of the engine's root context may cause conflicts or other
 issues in the library user's code.
 
+\note When using the CMake \l qt_add_qml_module API, a plugin will be generated
+automatically for you. It will take care of type registration.
+You only need to write a custom plugin if you have special
+requirements, such as registering custom image
+providers. In that case, pass
+\l{NO_GENERATE_PLUGIN_SOURCE} to the \c qt_add_qml_module
+call to disable the generation of the default plugin.
+
 The linker might erroneously remove the generated type registration
 function as an optimization. You can prevent that by declaring a synthetic
 volatile pointer to the function somewhere in your code. If your module is
diff --git a/src/qml/doc/src/qmllanguageref/syntax/directoryimports.qdoc b/src/qml/doc/src/qmllanguageref/syntax/directoryimports.qdoc
index 7ec8a4ff34..0623dd9934 100644
--- a/src/qml/doc/src/qmllanguageref/syntax/directoryimports.qdoc
+++ b/src/qml/doc/src/qmllanguageref/syntax/directoryimports.qdoc
@@ -109,6 +109,11 @@ a file system path.
 A directory of QML files can also be imported from a remote location if the
 directory contains a directory listing \c qmldir file.
 
+\note This also holds for the implicit import of the directory a QML document
+resides in. If your QML documents are loaded from a remote location, you need
+to add qmldir files even if they don't contain any explicit directory import
+statements. Otherwise your QML documents won't see each other.
+
 For example, if the \c myapp directory in the previous example was hosted at
 "http://www.my-example-server.com", and the \c mycomponents directory
 contained a \c qmldir file defined as follows:
diff --git a/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc b/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc
index 6ddd9f30d0..8b3ff59ecc 100644
--- a/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc
+++ b/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc
@@ -56,6 +56,7 @@ The set of QML object-type attribute types is as follows:
 These attributes are discussed in detail below.
 
 \section2 The \e id Attribute
+\keyword QML.id
 
 Every QML object type has exactly one \e id attribute. This attribute is
 provided by the language itself, and cannot be redefined or overridden by any
@@ -686,8 +687,8 @@ the role names of the view's model, then those properties will be initialized
 with the model's corresponding values.
 For more information, visit the \l{Models and Views in Qt Quick} page.
 
-\sa {QQmlComponent::createWithInitialProperties}, {QQmlApplicationEngine::setInitialProperties}
-and {QQuickView::setInitialProperties} for ways to initialize required properties from C++.
+See \l{QQmlComponent::createWithInitialProperties}, \l{QQmlApplicationEngine::setInitialProperties}
+and \l{QQuickView::setInitialProperties} for ways to initialize required properties from C++.
 
 \section3 Read-Only Properties
 
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 6f91f0151b..8eb7d8982d 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -356,6 +356,9 @@ ExecutionEngine::ExecutionEngine(QJSEngine *jsEngine)
     if (ok && envMaxGCStackSize > 0)
         m_maxGCStackSize = envMaxGCStackSize;
 
+    // We allocate guard pages around our stacks.
+    const size_t guardPages = 2 * WTF::pageSize();
+
     memoryManager = new QV4::MemoryManager(this);
 
     if (maxCallDepth == -1) {
@@ -368,6 +371,8 @@ ExecutionEngine::ExecutionEngine(QJSEngine *jsEngine)
 #if defined(QT_NO_DEBUG) && !defined(__SANITIZE_ADDRESS__) && !__has_feature(address_sanitizer)
 #ifdef Q_OS_QNX
                 maxCallDepth = 640; // QNX's stack is only 512k by default
+#elif defined(Q_OS_WIN)
+                maxCallDepth = 640; // We've seen crashes around 750.
 #else
                 maxCallDepth = 1234;
 #endif
@@ -383,9 +388,9 @@ ExecutionEngine::ExecutionEngine(QJSEngine *jsEngine)
     // reserve space for the JS stack
     // we allow it to grow to a bit more than m_maxJSStackSize, as we can overshoot due to ScopedValues
     // allocated outside of JIT'ed methods.
-    *jsStack = WTF::PageAllocation::allocate(m_maxJSStackSize + 256*1024, WTF::OSAllocator::JSVMStackPages,
-                                             /* writable */ true, /* executable */ false,
-                                             /* includesGuardPages */ true);
+    *jsStack = WTF::PageAllocation::allocate(
+                m_maxJSStackSize + 256*1024 + guardPages, WTF::OSAllocator::JSVMStackPages,
+                /* writable */ true, /* executable */ false, /* includesGuardPages */ true);
     jsStackBase = (Value *)jsStack->base();
 #ifdef V4_USE_VALGRIND
     VALGRIND_MAKE_MEM_UNDEFINED(jsStackBase, m_maxJSStackSize + 256*1024);
@@ -393,9 +398,9 @@ ExecutionEngine::ExecutionEngine(QJSEngine *jsEngine)
 
     jsStackTop = jsStackBase;
 
-    *gcStack = WTF::PageAllocation::allocate(m_maxGCStackSize, WTF::OSAllocator::JSVMStackPages,
-                                             /* writable */ true, /* executable */ false,
-                                             /* includesGuardPages */ true);
+    *gcStack = WTF::PageAllocation::allocate(
+                m_maxGCStackSize + guardPages, WTF::OSAllocator::JSVMStackPages,
+                /* writable */ true, /* executable */ false, /* includesGuardPages */ true);
 
     {
         ok = false;
@@ -2192,7 +2197,7 @@ void ExecutionEngine::setQmlEngine(QQmlEngine *engine)
 
 static void freeze_recursive(QV4::ExecutionEngine *v4, QV4::Object *object)
 {
-    if (object->as<QV4::QObjectWrapper>() || object->internalClass()->isFrozen)
+    if (object->as<QV4::QObjectWrapper>() || object->internalClass()->isFrozen())
         return;
 
     QV4::Scope scope(v4);
@@ -2301,6 +2306,8 @@ bool ExecutionEngine::metaTypeFromJS(const Value &value, QMetaType metaType, voi
     case QMetaType::QByteArray:
         if (const ArrayBuffer *ab = value.as<ArrayBuffer>())
             *reinterpret_cast<QByteArray*>(data) = ab->asByteArray();
+        else if (const String *string = value.as<String>())
+            *reinterpret_cast<QByteArray*>(data) = string->toQString().toUtf8();
         else
             *reinterpret_cast<QByteArray*>(data) = QByteArray();
         return true;
diff --git a/src/qml/jsruntime/qv4global_p.h b/src/qml/jsruntime/qv4global_p.h
index 1493456853..0abdd76c96 100644
--- a/src/qml/jsruntime/qv4global_p.h
+++ b/src/qml/jsruntime/qv4global_p.h
@@ -307,7 +307,6 @@ struct PropertyAttributes
     void clear() { m_all = 0; }
     bool isEmpty() const { return !m_all; }
 
-    uint flags() const { return m_flags; }
     uint all() const { return m_all; }
 
     bool operator==(PropertyAttributes other) {
diff --git a/src/qml/jsruntime/qv4internalclass.cpp b/src/qml/jsruntime/qv4internalclass.cpp
index 4287563c94..eabb220c50 100644
--- a/src/qml/jsruntime/qv4internalclass.cpp
+++ b/src/qml/jsruntime/qv4internalclass.cpp
@@ -178,7 +178,7 @@ void SharedInternalClassDataPrivate<PropertyKey>::setSize(uint s)
     data->values.size = s;
 }
 
-PropertyKey SharedInternalClassDataPrivate<PropertyKey>::at(uint i)
+PropertyKey SharedInternalClassDataPrivate<PropertyKey>::at(uint i) const
 {
     Q_ASSERT(data && i < size());
     return PropertyKey::fromId(data->values.values[i].rawValue());
@@ -265,6 +265,13 @@ namespace Heap {
 
 void InternalClass::init(ExecutionEngine *engine)
 {
+//    InternalClass is automatically zeroed during allocation:
+//    prototype = nullptr;
+//    parent = nullptr;
+//    size = 0;
+//    numRedundantTransitions = 0;
+//    flags = 0;
+
     Base::init();
     new (&propertyTable) PropertyHash();
     new (&nameMap) SharedInternalClassData<PropertyKey>(engine);
@@ -273,13 +280,6 @@ void InternalClass::init(ExecutionEngine *engine)
 
     this->engine = engine;
     vtable = QV4::InternalClass::staticVTable();
-//    prototype = nullptr;
-//    parent = nullptr;
-//    size = 0;
-    extensible = true;
-    isFrozen = false;
-    isSealed = false;
-    isUsedAsProto = false;
     protoId = engine->newProtoId();
 
     // Also internal classes need an internal class pointer. Simply make it point to itself
@@ -300,10 +300,8 @@ void InternalClass::init(Heap::InternalClass *other)
     prototype = other->prototype;
     parent = other;
     size = other->size;
-    extensible = other->extensible;
-    isSealed = other->isSealed;
-    isFrozen = other->isFrozen;
-    isUsedAsProto = other->isUsedAsProto;
+    numRedundantTransitions = other->numRedundantTransitions;
+    flags = other->flags;
     protoId = engine->newProtoId();
 
     internalClass.set(engine, other->internalClass);
@@ -365,7 +363,99 @@ static void addDummyEntry(InternalClass *newClass, PropertyHash::Entry e)
     ++newClass->size;
 }
 
-Heap::InternalClass *InternalClass::changeMember(PropertyKey identifier, PropertyAttributes data, InternalClassEntry *entry)
+static PropertyAttributes attributesFromFlags(int flags)
+{
+    PropertyAttributes attributes;
+    attributes.m_all = uchar(flags);
+    return attributes;
+}
+
+static Heap::InternalClass *cleanInternalClass(Heap::InternalClass *orig)
+{
+    if (++orig->numRedundantTransitions < Heap::InternalClass::MaxRedundantTransitions)
+        return orig;
+
+    // We will generally add quite a few transitions here. We have 255 redundant ones.
+    // We can expect at least as many significant ones in addition.
+    std::vector<InternalClassTransition> transitions;
+
+    Scope scope(orig->engine);
+    Scoped<QV4::InternalClass> child(scope, orig);
+
+    {
+        quint8 remainingRedundantTransitions = orig->numRedundantTransitions;
+        QSet<PropertyKey> properties;
+        int structureChanges = 0;
+
+        Scoped<QV4::InternalClass> parent(scope, orig->parent);
+        while (parent && remainingRedundantTransitions > 0) {
+            Q_ASSERT(child->d() != scope.engine->classes[ExecutionEngine::Class_Empty]);
+            const auto it = std::find_if(
+                        parent->d()->transitions.begin(), parent->d()->transitions.end(),
+                        [&child](const InternalClassTransition &t) {
+                return child->d() == t.lookup;
+            });
+            Q_ASSERT(it != parent->d()->transitions.end());
+
+            if (it->flags & InternalClassTransition::StructureChange) {
+                // A structural change. Each kind of structural change has to be recorded only once.
+                if ((structureChanges & it->flags) != it->flags) {
+                    transitions.push_back(*it);
+                    structureChanges |= it->flags;
+                } else {
+                    --remainingRedundantTransitions;
+                }
+            } else if (!properties.contains(it->id)) {
+                // We only need the final state of the property.
+                properties.insert(it->id);
+
+                // Property removal creates _two_ redundant transitions.
+                // We don't have to replay either, but numRedundantTransitions only records one.
+                if (it->flags != 0)
+                    transitions.push_back(*it);
+            } else {
+                --remainingRedundantTransitions;
+            }
+
+            child = parent->d();
+            parent = child->d()->parent;
+            Q_ASSERT(child->d() != parent->d());
+        }
+    }
+
+    for (auto it = transitions.rbegin(); it != transitions.rend(); ++it) {
+        switch (it->flags) {
+        case InternalClassTransition::NotExtensible:
+            child = child->d()->nonExtensible();
+            continue;
+        case InternalClassTransition::VTableChange:
+            child = child->d()->changeVTable(it->vtable);
+            continue;
+        case InternalClassTransition::PrototypeChange:
+            child = child->d()->changePrototype(it->prototype);
+            continue;
+        case InternalClassTransition::ProtoClass:
+            child = child->d()->asProtoClass();
+            continue;
+        case InternalClassTransition::Sealed:
+            child = child->d()->sealed();
+            continue;
+        case InternalClassTransition::Frozen:
+            child = child->d()->frozen();
+            continue;
+        default:
+            Q_ASSERT(it->flags != 0);
+            Q_ASSERT(it->flags < InternalClassTransition::StructureChange);
+            child = child->addMember(it->id, attributesFromFlags(it->flags));
+            continue;
+        }
+    }
+
+    return child->d();
+}
+
+Heap::InternalClass *InternalClass::changeMember(
+        PropertyKey identifier, PropertyAttributes data, InternalClassEntry *entry)
 {
     if (!data.isEmpty())
         data.resolve();
@@ -381,7 +471,7 @@ Heap::InternalClass *InternalClass::changeMember(PropertyKey identifier, Propert
     }
 
     if (data == propertyData.at(idx))
-        return static_cast<Heap::InternalClass *>(this);
+        return this;
 
     Transition temp = { { identifier }, nullptr, int(data.all()) };
     Transition &t = lookupOrInsertTransition(temp);
@@ -394,7 +484,8 @@ Heap::InternalClass *InternalClass::changeMember(PropertyKey identifier, Propert
         Q_ASSERT(!propertyData.at(idx).isAccessor());
 
         // add a dummy entry for the accessor
-        entry->setterIndex = newClass->size;
+        if (entry)
+            entry->setterIndex = newClass->size;
         e->setterIndex = newClass->size;
         addDummyEntry(newClass, *e);
     }
@@ -403,7 +494,8 @@ Heap::InternalClass *InternalClass::changeMember(PropertyKey identifier, Propert
 
     t.lookup = newClass;
     Q_ASSERT(t.lookup);
-    return newClass;
+
+    return cleanInternalClass(newClass);
 }
 
 Heap::InternalClass *InternalClass::changePrototypeImpl(Heap::Object *proto)
@@ -413,7 +505,7 @@ Heap::InternalClass *InternalClass::changePrototypeImpl(Heap::Object *proto)
     if (proto)
         proto->setUsedAsProto();
     Q_ASSERT(prototype != proto);
-    Q_ASSERT(!proto || proto->internalClass->isUsedAsProto);
+    Q_ASSERT(!proto || proto->internalClass->isUsedAsProto());
 
     Transition temp = { { PropertyKey::invalid() }, nullptr, Transition::PrototypeChange };
     temp.prototype = proto;
@@ -427,8 +519,7 @@ Heap::InternalClass *InternalClass::changePrototypeImpl(Heap::Object *proto)
     newClass->prototype = proto;
 
     t.lookup = newClass;
-
-    return newClass;
+    return prototype ? cleanInternalClass(newClass) : newClass;
 }
 
 Heap::InternalClass *InternalClass::changeVTableImpl(const VTable *vt)
@@ -449,12 +540,14 @@ Heap::InternalClass *InternalClass::changeVTableImpl(const VTable *vt)
     t.lookup = newClass;
     Q_ASSERT(t.lookup);
     Q_ASSERT(newClass->vtable);
-    return newClass;
+    return vtable == QV4::InternalClass::staticVTable()
+            ? newClass
+            : cleanInternalClass(newClass);
 }
 
 Heap::InternalClass *InternalClass::nonExtensible()
 {
-    if (!extensible)
+    if (!isExtensible())
         return this;
 
     Transition temp = { { PropertyKey::invalid() }, nullptr, Transition::NotExtensible};
@@ -463,7 +556,7 @@ Heap::InternalClass *InternalClass::nonExtensible()
         return t.lookup;
 
     Heap::InternalClass *newClass = engine->newClass(this);
-    newClass->extensible = false;
+    newClass->flags |= NotExtensible;
 
     t.lookup = newClass;
     Q_ASSERT(t.lookup);
@@ -500,7 +593,7 @@ Heap::InternalClass *InternalClass::addMember(PropertyKey identifier, PropertyAt
 
 Heap::InternalClass *InternalClass::addMemberImpl(PropertyKey identifier, PropertyAttributes data, InternalClassEntry *entry)
 {
-    Transition temp = { { identifier }, nullptr, (int)data.flags() };
+    Transition temp = { { identifier }, nullptr, int(data.all()) };
     Transition &t = lookupOrInsertTransition(temp);
 
     if (entry) {
@@ -553,21 +646,23 @@ void InternalClass::removeMember(QV4::Object *object, PropertyKey identifier)
     changeMember(object, identifier, Attr_Invalid);
 
 #ifndef QT_NO_DEBUG
-    // we didn't remove the data slot, just made it inaccessible
-    Q_ASSERT(object->internalClass()->size == oldClass->size);
+    // We didn't remove the data slot, just made it inaccessible.
+    // ... unless we've rebuilt the whole class. Then all the deleted properties are gone.
+    Q_ASSERT(object->internalClass()->numRedundantTransitions == 0
+             || object->internalClass()->size == oldClass->size);
 #endif
 }
 
 Heap::InternalClass *InternalClass::sealed()
 {
-    if (isSealed)
+    if (isSealed())
         return this;
 
     Transition temp = { { PropertyKey::invalid() }, nullptr, InternalClassTransition::Sealed };
     Transition &t = lookupOrInsertTransition(temp);
 
     if (t.lookup) {
-        Q_ASSERT(t.lookup && t.lookup->isSealed);
+        Q_ASSERT(t.lookup && t.lookup->isSealed());
         return t.lookup;
     }
 
@@ -575,7 +670,7 @@ Heap::InternalClass *InternalClass::sealed()
     Scoped<QV4::InternalClass> ic(scope, engine->newClass(this));
     Heap::InternalClass *s = ic->d();
 
-    if (!isFrozen) { // freezing also makes all properties non-configurable
+    if (!isFrozen()) { // freezing also makes all properties non-configurable
         for (uint i = 0; i < size; ++i) {
             PropertyAttributes attrs = propertyData.at(i);
             if (attrs.isEmpty())
@@ -584,7 +679,7 @@ Heap::InternalClass *InternalClass::sealed()
             s->propertyData.set(i, attrs);
         }
     }
-    s->isSealed = true;
+    s->flags |= Sealed;
 
     t.lookup = s;
     return s;
@@ -592,14 +687,14 @@ Heap::InternalClass *InternalClass::sealed()
 
 Heap::InternalClass *InternalClass::frozen()
 {
-    if (isFrozen)
+    if (isFrozen())
         return this;
 
     Transition temp = { { PropertyKey::invalid() }, nullptr, InternalClassTransition::Frozen };
     Transition &t = lookupOrInsertTransition(temp);
 
     if (t.lookup) {
-        Q_ASSERT(t.lookup && t.lookup->isFrozen);
+        Q_ASSERT(t.lookup && t.lookup->isFrozen());
         return t.lookup;
     }
 
@@ -616,7 +711,7 @@ Heap::InternalClass *InternalClass::frozen()
         attrs.setConfigurable(false);
         f->propertyData.set(i, attrs);
     }
-    f->isFrozen = true;
+    f->flags |= Frozen;
 
     t.lookup = f;
     return f;
@@ -640,7 +735,7 @@ InternalClass *InternalClass::cryopreserved()
 
 bool InternalClass::isImplicitlyFrozen() const
 {
-    if (isFrozen)
+    if (isFrozen())
         return true;
 
     for (uint i = 0; i < size; ++i) {
@@ -656,7 +751,7 @@ bool InternalClass::isImplicitlyFrozen() const
 
 Heap::InternalClass *InternalClass::asProtoClass()
 {
-    if (isUsedAsProto)
+    if (isUsedAsProto())
         return this;
 
     Transition temp = { { PropertyKey::invalid() }, nullptr, Transition::ProtoClass };
@@ -665,7 +760,7 @@ Heap::InternalClass *InternalClass::asProtoClass()
         return t.lookup;
 
     Heap::InternalClass *newClass = engine->newClass(this);
-    newClass->isUsedAsProto = true;
+    newClass->flags |= UsedAsProto;
 
     t.lookup = newClass;
     Q_ASSERT(t.lookup);
@@ -685,7 +780,7 @@ static void updateProtoUsage(Heap::Object *o, Heap::InternalClass *ic)
 
 void InternalClass::updateProtoUsage(Heap::Object *o)
 {
-    Q_ASSERT(isUsedAsProto);
+    Q_ASSERT(isUsedAsProto());
     Heap::InternalClass *ic = engine->internalClasses(EngineBase::Class_Empty);
     Q_ASSERT(!ic->prototype);
 
@@ -698,6 +793,9 @@ void InternalClass::markObjects(Heap::Base *b, MarkStack *stack)
     if (ic->prototype)
         ic->prototype->mark(stack);
 
+    if (ic->parent)
+        ic->parent->mark(stack);
+
     ic->nameMap.mark(stack);
 }
 
diff --git a/src/qml/jsruntime/qv4internalclass_p.h b/src/qml/jsruntime/qv4internalclass_p.h
index c18133f4cd..37dbeded6f 100644
--- a/src/qml/jsruntime/qv4internalclass_p.h
+++ b/src/qml/jsruntime/qv4internalclass_p.h
@@ -173,7 +173,7 @@ struct SharedInternalClassDataPrivate<PropertyAttributes> {
     uint size() const { return m_size; }
     void setSize(uint s) { m_size = s; }
 
-    PropertyAttributes at(uint i) { Q_ASSERT(data && i < m_alloc); return data[i]; }
+    PropertyAttributes at(uint i) const { Q_ASSERT(data && i < m_alloc); return data[i]; }
     void set(uint i, PropertyAttributes t) { Q_ASSERT(data && i < m_alloc); data[i] = t; }
 
     void mark(MarkStack *) {}
@@ -198,7 +198,7 @@ struct SharedInternalClassDataPrivate<PropertyKey> {
     uint size() const;
     void setSize(uint s);
 
-    PropertyKey at(uint i);
+    PropertyKey at(uint i) const;
     void set(uint i, PropertyKey t);
 
     void mark(MarkStack *s);
@@ -289,24 +289,33 @@ struct InternalClassTransition
     int flags;
     enum {
         // range 0-0xff is reserved for attribute changes
-        NotExtensible = 0x100,
-        VTableChange = 0x200,
-        PrototypeChange = 0x201,
-        ProtoClass = 0x202,
-        Sealed = 0x203,
-        Frozen = 0x204
+        StructureChange = 0x100,
+        NotExtensible   = StructureChange | (1 << 0),
+        VTableChange    = StructureChange | (1 << 1),
+        PrototypeChange = StructureChange | (1 << 2),
+        ProtoClass      = StructureChange | (1 << 3),
+        Sealed          = StructureChange | (1 << 4),
+        Frozen          = StructureChange | (1 << 5),
     };
 
     bool operator==(const InternalClassTransition &other) const
     { return id == other.id && flags == other.flags; }
 
     bool operator<(const InternalClassTransition &other) const
-    { return id < other.id || (id == other.id && flags < other.flags); }
+    { return flags < other.flags || (flags == other.flags && id < other.id); }
 };
 
 namespace Heap {
 
 struct InternalClass : Base {
+    enum Flag {
+        NotExtensible = 1 << 0,
+        Sealed        = 1 << 1,
+        Frozen        = 1 << 2,
+        UsedAsProto   = 1 << 3,
+    };
+    enum { MaxRedundantTransitions = 255 };
+
     ExecutionEngine *engine;
     const VTable *vtable;
     quintptr protoId; // unique across the engine, gets changed whenever the proto chain changes
@@ -322,10 +331,13 @@ struct InternalClass : Base {
     InternalClassTransition &lookupOrInsertTransition(const InternalClassTransition &t);
 
     uint size;
-    bool extensible;
-    bool isSealed;
-    bool isFrozen;
-    bool isUsedAsProto;
+    quint8 numRedundantTransitions;
+    quint8 flags;
+
+    bool isExtensible() const { return !(flags & NotExtensible); }
+    bool isSealed() const { return flags & Sealed; }
+    bool isFrozen() const { return flags & Frozen; }
+    bool isUsedAsProto() const { return flags & UsedAsProto; }
 
     void init(ExecutionEngine *engine);
     void init(InternalClass *other);
diff --git a/src/qml/jsruntime/qv4jscall_p.h b/src/qml/jsruntime/qv4jscall_p.h
index c6d320ac20..70ddaf59c5 100644
--- a/src/qml/jsruntime/qv4jscall_p.h
+++ b/src/qml/jsruntime/qv4jscall_p.h
@@ -146,10 +146,12 @@ struct ScopedStackFrame {
             return;
         frame.jsFrame = reinterpret_cast<CallData *>(scope.alloc(sizeof(CallData)/sizeof(Value)));
         frame.jsFrame->context = context;
-        if (auto *parent = frame.parentFrame())
+        if (auto *parent = frame.parentFrame()) {
             frame.v4Function = parent->v4Function;
-        else
+            frame.instructionPointer = parent->instructionPointer;
+        } else {
             frame.v4Function = nullptr;
+        }
         scope.engine->currentStackFrame = &frame;
     }
     ~ScopedStackFrame() {
diff --git a/src/qml/jsruntime/qv4jsonobject.cpp b/src/qml/jsruntime/qv4jsonobject.cpp
index a3ffdb5431..994d9a79a0 100644
--- a/src/qml/jsruntime/qv4jsonobject.cpp
+++ b/src/qml/jsruntime/qv4jsonobject.cpp
@@ -646,6 +646,28 @@ struct Stringify
     QString makeMember(const QString &key, const Value &v);
 };
 
+class [[nodiscard]] CallDepthAndCycleChecker
+{
+    Q_DISABLE_COPY_MOVE(CallDepthAndCycleChecker);
+
+public:
+    CallDepthAndCycleChecker(Stringify *stringify, Object *o)
+        : m_callDepthRecorder(stringify->v4)
+    {
+        if (stringify->stackContains(o)) {
+            stringify->v4->throwTypeError(
+                        QStringLiteral("Cannot convert circular structure to JSON"));
+        }
+
+        stringify->v4->checkStackLimits();
+    }
+
+    bool foundProblem() const { return m_callDepthRecorder.ee->hasException; }
+
+private:
+    ExecutionEngineCallDepthRecorder m_callDepthRecorder;
+};
+
 static QString quote(const QString &str)
 {
     QString product;
@@ -776,10 +798,9 @@ QString Stringify::makeMember(const QString &key, const Value &v)
 
 QString Stringify::JO(Object *o)
 {
-    if (stackContains(o)) {
-        v4->throwTypeError();
+    CallDepthAndCycleChecker check(this, o);
+    if (check.foundProblem())
         return QString();
-    }
 
     Scope scope(v4);
 
@@ -836,10 +857,9 @@ QString Stringify::JO(Object *o)
 
 QString Stringify::JA(Object *a)
 {
-    if (stackContains(a)) {
-        v4->throwTypeError();
+    CallDepthAndCycleChecker check(this, a);
+    if (check.foundProblem())
         return QString();
-    }
 
     Scope scope(a->engine());
 
diff --git a/src/qml/jsruntime/qv4object.cpp b/src/qml/jsruntime/qv4object.cpp
index c10f1b46c3..564cd47203 100644
--- a/src/qml/jsruntime/qv4object.cpp
+++ b/src/qml/jsruntime/qv4object.cpp
@@ -61,17 +61,52 @@ DEFINE_OBJECT_VTABLE(Object);
 
 void Object::setInternalClass(Heap::InternalClass *ic)
 {
-    d()->internalClass.set(engine(), ic);
-    if (ic->isUsedAsProto)
-        ic->updateProtoUsage(d());
     Q_ASSERT(ic && ic->vtable);
-    uint nInline = d()->vtable()->nInlineProperties;
-    if (ic->size <= nInline)
-        return;
-    bool hasMD = d()->memberData != nullptr;
-    uint requiredSize = ic->size - nInline;
-    if (!(hasMD && requiredSize) || (hasMD && d()->memberData->values.size < requiredSize))
-        d()->memberData.set(ic->engine, MemberData::allocate(ic->engine, requiredSize, d()->memberData));
+    Heap::Object *p = d();
+
+    if (ic->numRedundantTransitions < p->internalClass.get()->numRedundantTransitions) {
+        // IC was rebuilt. The indices are different now. We need to move everything.
+
+        Scope scope(engine());
+
+        // We allocate before setting the new IC. Protect it from GC.
+        Scoped<InternalClass> newIC(scope, ic);
+
+        // Pick the members of the old IC that are still valid in the new IC.
+        // Order them by index in memberData (or inline data).
+        Scoped<MemberData> newMembers(scope, MemberData::allocate(scope.engine, ic->size));
+        for (uint i = 0; i < ic->size; ++i)
+            newMembers->set(scope.engine, i, get(ic->nameMap.at(i)));
+
+        p->internalClass.set(scope.engine, ic);
+        const uint nInline = p->vtable()->nInlineProperties;
+
+        if (ic->size > nInline)
+            p->memberData.set(scope.engine, MemberData::allocate(ic->engine, ic->size - nInline));
+        else
+            p->memberData.set(scope.engine, nullptr);
+
+        const auto &memberValues = newMembers->d()->values;
+        for (uint i = 0; i < ic->size; ++i)
+            setProperty(i, memberValues[i]);
+    } else {
+        // The old indices are still the same. No need to move any values.
+        // We may need to re-allocate, though.
+
+        p->internalClass.set(ic->engine, ic);
+        const uint nInline = p->vtable()->nInlineProperties;
+        if (ic->size > nInline) {
+            const uint requiredSize = ic->size - nInline;
+            if ((p->memberData ? p->memberData->values.size : 0) < requiredSize) {
+                p->memberData.set(ic->engine, MemberData::allocate(
+                                      ic->engine, requiredSize, p->memberData));
+            }
+        }
+    }
+
+    if (ic->isUsedAsProto())
+        ic->updateProtoUsage(p);
+
 }
 
 void Object::getProperty(const InternalClassEntry &entry, Property *p) const
@@ -958,7 +993,7 @@ bool Object::virtualDefineOwnProperty(Managed *m, PropertyKey id, const Property
 
 bool Object::virtualIsExtensible(const Managed *m)
 {
-    return m->d()->internalClass->extensible;
+    return m->d()->internalClass->isExtensible();
 }
 
 bool Object::virtualPreventExtensions(Managed *m)
@@ -982,7 +1017,7 @@ bool Object::virtualSetPrototypeOf(Managed *m, const Object *proto)
     Heap::Object *protod = proto ? proto->d() : nullptr;
     if (current == protod)
         return true;
-    if (!o->internalClass()->extensible)
+    if (!o->internalClass()->isExtensible())
         return false;
     Heap::Object *p = protod;
     while (p) {
diff --git a/src/qml/jsruntime/qv4promiseobject.cpp b/src/qml/jsruntime/qv4promiseobject.cpp
index 83bfba9b11..e155f2c3ba 100644
--- a/src/qml/jsruntime/qv4promiseobject.cpp
+++ b/src/qml/jsruntime/qv4promiseobject.cpp
@@ -116,6 +116,8 @@ struct ResolveThenableEvent : public QEvent
 } // namespace QV4
 QT_END_NAMESPACE
 
+#include "moc_qv4promiseobject_p.cpp"
+
 ReactionHandler::ReactionHandler(QObject *parent)
     : QObject(parent)
 {}
diff --git a/src/qml/jsruntime/qv4propertykey_p.h b/src/qml/jsruntime/qv4propertykey_p.h
index b5dca2d2ac..bb93dc518d 100644
--- a/src/qml/jsruntime/qv4propertykey_p.h
+++ b/src/qml/jsruntime/qv4propertykey_p.h
@@ -51,6 +51,7 @@
 //
 
 #include <private/qv4global_p.h>
+#include <QtCore/qhashfunctions.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -145,6 +146,7 @@ public:
     bool operator ==(const PropertyKey &other) const { return val == other.val; }
     bool operator !=(const PropertyKey &other) const { return val != other.val; }
     bool operator <(const PropertyKey &other) const { return val < other.val; }
+    friend size_t qHash(const PropertyKey &key, size_t seed = 0) { return qHash(key.val, seed); }
 };
 
 }
diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index 21ac5e448a..c897c63024 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -777,7 +777,7 @@ bool QObjectWrapper::virtualPut(Managed *m, PropertyKey id, const Value &value,
     QObjectWrapper *that = static_cast<QObjectWrapper*>(m);
     ScopedString name(scope, id.asStringOrSymbol());
 
-    if (that->internalClass()->isFrozen) {
+    if (that->internalClass()->isFrozen()) {
         QString error = QLatin1String("Cannot assign to property \"") +
                         name->toQString() + QLatin1String("\" of read-only object");
         scope.engine->throwError(error);
diff --git a/src/qml/jsruntime/qv4sequenceobject.cpp b/src/qml/jsruntime/qv4sequenceobject.cpp
index 01edfd5964..b0268afedd 100644
--- a/src/qml/jsruntime/qv4sequenceobject.cpp
+++ b/src/qml/jsruntime/qv4sequenceobject.cpp
@@ -709,3 +709,5 @@ int SequencePrototype::metaTypeForSequence(const QV4::Object *object)
 }
 
 QT_END_NAMESPACE
+
+#include "moc_qv4sequenceobject_p.cpp"
diff --git a/src/qml/jsruntime/qv4stackframe.cpp b/src/qml/jsruntime/qv4stackframe.cpp
index a716c53aea..0a060e81a7 100644
--- a/src/qml/jsruntime/qv4stackframe.cpp
+++ b/src/qml/jsruntime/qv4stackframe.cpp
@@ -53,7 +53,7 @@ QString CppStackFrame::function() const
 
 int CppStackFrame::lineNumber() const
 {
-    if (!v4Function)
+    if (!v4Function || instructionPointer <= 0)
         return -1;
 
     auto findLine = [](const CompiledData::CodeOffsetToLine &entry, uint offset) {
@@ -61,9 +61,9 @@ int CppStackFrame::lineNumber() const
     };
 
     const QV4::CompiledData::Function *cf = v4Function->compiledFunction;
-    uint offset = instructionPointer;
+    const uint offset = instructionPointer;
     const CompiledData::CodeOffsetToLine *lineNumbers = cf->lineNumberTable();
-    uint nLineNumbers = cf->nLineNumbers;
+    const uint nLineNumbers = cf->nLineNumbers;
     const CompiledData::CodeOffsetToLine *line = std::lower_bound(lineNumbers, lineNumbers + nLineNumbers, offset, findLine) - 1;
     return line->line;
 }
diff --git a/src/qml/qml/ftw/qintrusivelist_p.h b/src/qml/qml/ftw/qintrusivelist_p.h
index 8992be9f93..40dc45095f 100644
--- a/src/qml/qml/ftw/qintrusivelist_p.h
+++ b/src/qml/qml/ftw/qintrusivelist_p.h
@@ -241,7 +241,12 @@ typename QIntrusiveList<N, member>::iterator QIntrusiveList<N, member>::end()
 template<class N, QIntrusiveListNode N::*member>
 N *QIntrusiveList<N, member>::nodeToN(QIntrusiveListNode *node)
 {
+    QT_WARNING_PUSH
+#if defined(Q_CC_CLANG) && Q_CC_CLANG >= 1300
+    QT_WARNING_DISABLE_CLANG("-Wnull-pointer-subtraction")
+#endif
     return (N *)((char *)node - ((char *)&(((N *)nullptr)->*member) - (char *)nullptr));
+    QT_WARNING_POP
 }
 
 QIntrusiveListNode::QIntrusiveListNode()
diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index 9a15fa5358..064eddc76a 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -833,8 +833,16 @@ QObject *QQmlComponent::create(QQmlContext *context)
     Q_D(QQmlComponent);
 
     QObject *rv = d->doBeginCreate(this, context);
-    if (rv)
+    if (rv) {
         completeCreate();
+    } else if (d->state.completePending) {
+        // overridden completCreate might assume that
+        // the object has actually been created
+        ++creationDepth.localData();
+        QQmlEnginePrivate *ep = QQmlEnginePrivate::get(d->engine);
+        d->complete(ep, &d->state);
+        --creationDepth.localData();
+    }
     if (rv && !d->requiredProperties().empty()) {
         delete  rv;
         return nullptr;
@@ -1793,3 +1801,4 @@ void QV4::QmlIncubatorObject::statusChanged(QQmlIncubator::Status s)
 QT_END_NAMESPACE
 
 #include "moc_qqmlcomponent.cpp"
+#include "moc_qqmlcomponentattached_p.cpp"
diff --git a/src/qml/qml/qqmlcomponentattached_p.h b/src/qml/qml/qqmlcomponentattached_p.h
index b94d474d1f..2e63289c2d 100644
--- a/src/qml/qml/qqmlcomponentattached_p.h
+++ b/src/qml/qml/qqmlcomponentattached_p.h
@@ -58,6 +58,7 @@
 QT_BEGIN_NAMESPACE
 
 
+// implemented in qqmlcomponent.cpp
 class Q_QML_PRIVATE_EXPORT QQmlComponentAttached : public QObject
 {
     Q_OBJECT
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 080ecfe323..3a2f678419 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -2290,4 +2290,6 @@ bool QQml_isFileCaseCorrect(const QString &fileName, int lengthIn /* = -1 */)
 
 QT_END_NAMESPACE
 
+#include "moc_qqmlengine_p.cpp"
+
 #include "moc_qqmlengine.cpp"
diff --git a/src/qml/qml/qqmlextensionplugin.cpp b/src/qml/qml/qqmlextensionplugin.cpp
index a14ecdc471..22846a84dc 100644
--- a/src/qml/qml/qqmlextensionplugin.cpp
+++ b/src/qml/qml/qqmlextensionplugin.cpp
@@ -169,7 +169,7 @@ void QQmlEngineExtensionPlugin::initializeEngine(QQmlEngine *engine, const char
 /*!
     \macro Q_IMPORT_QML_PLUGIN(PluginName)
     \since 6.2
-    \relates QQmlExtensionPlugin
+    \relates QQmlEngineExtensionPlugin
 
     Ensures the plugin whose metadata-declaring class is named \a PluginName
     is linked into static builds.
diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 3c89246870..a61cf4adea 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -226,7 +226,8 @@ static QQmlTypePrivate *createQQmlType(QQmlMetaTypeData *data, const QString &el
 }
 
 void QQmlMetaType::clone(QMetaObjectBuilder &builder, const QMetaObject *mo,
-                         const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd)
+                         const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd,
+                         QQmlMetaType::ClonePolicy policy)
 {
     // Set classname
     builder.setClassName(ignoreEnd->className());
@@ -243,40 +244,41 @@ void QQmlMetaType::clone(QMetaObjectBuilder &builder, const QMetaObject *mo,
         }
     }
 
-    // Clone Q_METHODS - do this first to avoid duplicating the notify signals.
-    for (int ii = mo->methodOffset(); ii < mo->methodCount(); ++ii) {
-        QMetaMethod method = mo->method(ii);
+    if (policy != QQmlMetaType::CloneEnumsOnly) {
+        // Clone Q_METHODS - do this first to avoid duplicating the notify signals.
+        for (int ii = mo->methodOffset(); ii < mo->methodCount(); ++ii) {
+            QMetaMethod method = mo->method(ii);
 
-        // More complex - need to search name
-        QByteArray name = method.name();
+            // More complex - need to search name
+            QByteArray name = method.name();
 
+            bool found = false;
 
-        bool found = false;
+            for (int ii = ignoreStart->methodOffset() + ignoreStart->methodCount();
+                 !found && ii < ignoreEnd->methodOffset() + ignoreEnd->methodCount(); ++ii) {
 
-        for (int ii = ignoreStart->methodOffset() + ignoreStart->methodCount();
-             !found && ii < ignoreEnd->methodOffset() + ignoreEnd->methodCount();
-             ++ii) {
+                QMetaMethod other = ignoreEnd->method(ii);
 
-            QMetaMethod other = ignoreEnd->method(ii);
+                found = name == other.name();
+            }
 
-            found = name == other.name();
+            QMetaMethodBuilder m = builder.addMethod(method);
+            if (found) // SKIP
+                m.setAccess(QMetaMethod::Private);
         }
 
-        QMetaMethodBuilder m = builder.addMethod(method);
-        if (found) // SKIP
-            m.setAccess(QMetaMethod::Private);
-    }
-
-    // Clone Q_PROPERTY
-    for (int ii = mo->propertyOffset(); ii < mo->propertyCount(); ++ii) {
-        QMetaProperty property = mo->property(ii);
+        // Clone Q_PROPERTY
+        for (int ii = mo->propertyOffset(); ii < mo->propertyCount(); ++ii) {
+            QMetaProperty property = mo->property(ii);
 
-        int otherIndex = ignoreEnd->indexOfProperty(property.name());
-        if (otherIndex >= ignoreStart->propertyOffset() + ignoreStart->propertyCount()) {
-            builder.addProperty(QByteArray("__qml_ignore__") + property.name(), QByteArray("void"));
-            // Skip
-        } else {
-            builder.addProperty(property);
+            int otherIndex = ignoreEnd->indexOfProperty(property.name());
+            if (otherIndex >= ignoreStart->propertyOffset() + ignoreStart->propertyCount()) {
+                builder.addProperty(QByteArray("__qml_ignore__") + property.name(),
+                                    QByteArray("void"));
+                // Skip
+            } else {
+                builder.addProperty(property);
+            }
         }
     }
 
@@ -1521,7 +1523,8 @@ QList<QQmlProxyMetaObject::ProxyData> QQmlMetaType::proxyData(const QMetaObject
             return;
 
         QMetaObjectBuilder builder;
-        clone(builder, extMetaObject, superdataBaseMetaObject, baseMetaObject);
+        clone(builder, extMetaObject, superdataBaseMetaObject, baseMetaObject,
+              extFunc ? QQmlMetaType::CloneAll : QQmlMetaType::CloneEnumsOnly);
         builder.setFlags(MetaObjectFlag::DynamicMetaObject);
         QMetaObject *mmo = builder.toMetaObject();
         mmo->d.superdata = baseMetaObject;
diff --git a/src/qml/qml/qqmlmetatype_p.h b/src/qml/qml/qqmlmetatype_p.h
index bd7e07373c..dc08263511 100644
--- a/src/qml/qml/qqmlmetatype_p.h
+++ b/src/qml/qml/qqmlmetatype_p.h
@@ -245,8 +245,13 @@ public:
                                                            const QMetaObject *baseMetaObject,
                                                            QMetaObject *lastMetaObject);
 
+    enum ClonePolicy {
+        CloneAll, // default
+        CloneEnumsOnly, // skip properties and methods
+    };
     static void clone(QMetaObjectBuilder &builder, const QMetaObject *mo,
-                      const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd);
+                      const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd,
+                      ClonePolicy policy);
 
     static void qmlInsertModuleRegistration(const QString &uri, void (*registerFunction)());
     static void qmlRemoveModuleRegistration(const QString &uri);
diff --git a/src/qml/qml/qqmlproperty.cpp b/src/qml/qml/qqmlproperty.cpp
index a9c9c03c3d..372103b94f 100644
--- a/src/qml/qml/qqmlproperty.cpp
+++ b/src/qml/qml/qqmlproperty.cpp
@@ -1799,3 +1799,5 @@ void QQmlPropertyPrivate::flushSignal(const QObject *sender, int signal_index)
 }
 
 QT_END_NAMESPACE
+
+#include "moc_qqmlproperty.cpp"
diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index a4b61cc22a..b03b8e937a 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -1067,6 +1067,7 @@ void QQmlPropertyCache::toMetaObjectBuilder(QMetaObjectBuilder &builder)
         property.setWritable(data->isWritable());
         property.setResettable(data->isResettable());
         property.setBindable(data->isBindable());
+        property.setAlias(data->isAlias());
     }
 
     for (int ii = 0; ii < methods.count(); ++ii) {
diff --git a/src/qml/qml/qqmlpropertycachecreator.cpp b/src/qml/qml/qqmlpropertycachecreator.cpp
index 2aab66b933..5c88761d78 100644
--- a/src/qml/qml/qqmlpropertycachecreator.cpp
+++ b/src/qml/qml/qqmlpropertycachecreator.cpp
@@ -149,6 +149,11 @@ void QQmlPendingGroupPropertyBindings::resolveMissingPropertyCaches(QQmlEnginePr
         if (propertyCaches->at(groupPropertyObjectIndex))
             continue;
 
+        if (!pendingBinding.referencingObjectPropertyCache) {
+            pendingBinding.referencingObjectPropertyCache
+                    = propertyCaches->at(pendingBinding.referencingObjectIndex);
+        }
+
         if (!pendingBinding.resolveInstantiatingProperty())
             continue;
 
diff --git a/src/qml/qml/qqmlpropertycachecreator_p.h b/src/qml/qml/qqmlpropertycachecreator_p.h
index c57d805dea..f4845ec27b 100644
--- a/src/qml/qml/qqmlpropertycachecreator_p.h
+++ b/src/qml/qml/qqmlpropertycachecreator_p.h
@@ -341,24 +341,24 @@ inline QQmlError QQmlPropertyCacheCreator<ObjectContainer>::buildMetaObjectRecur
         }
     }
 
-    if (QQmlPropertyCache *thisCache = propertyCaches->at(objectIndex)) {
-        auto binding = obj->bindingsBegin();
-        auto end = obj->bindingsEnd();
-        for ( ; binding != end; ++binding)
-            if (binding->type() >= QV4::CompiledData::Binding::Type_Object) {
-                QQmlBindingInstantiationContext context(objectIndex, &(*binding), stringAt(binding->propertyNameIndex), thisCache);
-
-                // Binding to group property where we failed to look up the type of the
-                // property? Possibly a group property that is an alias that's not resolved yet.
-                // Let's attempt to resolve it after we're done with the aliases and fill in the
-                // propertyCaches entry then.
-                if (!context.resolveInstantiatingProperty())
-                    pendingGroupPropertyBindings->append(context);
-
-                QQmlError error = buildMetaObjectRecursively(binding->value.objectIndex, context, VMEMetaObjectIsRequired::Maybe);
-                if (error.isValid())
-                    return error;
-            }
+    QQmlPropertyCache *thisCache = propertyCaches->at(objectIndex);
+    auto binding = obj->bindingsBegin();
+    auto end = obj->bindingsEnd();
+    for ( ; binding != end; ++binding) {
+        if (binding->type() >= QV4::CompiledData::Binding::Type_Object) {
+            QQmlBindingInstantiationContext context(objectIndex, &(*binding), stringAt(binding->propertyNameIndex), thisCache);
+
+            // Binding to group property where we failed to look up the type of the
+            // property? Possibly a group property that is an alias that's not resolved yet.
+            // Let's attempt to resolve it after we're done with the aliases and fill in the
+            // propertyCaches entry then.
+            if (!thisCache || !context.resolveInstantiatingProperty())
+                pendingGroupPropertyBindings->append(context);
+
+            QQmlError error = buildMetaObjectRecursively(binding->value.objectIndex, context, VMEMetaObjectIsRequired::Maybe);
+            if (error.isValid())
+                return error;
+        }
     }
 
     QQmlError noError;
@@ -901,10 +901,16 @@ inline QQmlError QQmlPropertyCacheAliasCreator<ObjectContainer>::propertyDataFor
         }
 
         const auto referencedType = typeRef->type();
-        if (referencedType.isValid())
+        if (referencedType.isValid()) {
             *type = referencedType.typeId();
-        else
+            if (!type->isValid() && referencedType.isInlineComponentType()) {
+                int objectId = referencedType.inlineComponentId();
+                *type = objectContainer->typeIdsForComponent(objectId).id;
+                Q_ASSERT(type->isValid());
+            }
+        } else {
             *type = typeRef->compilationUnit()->typeIds.id;
+        }
 
         *version = typeRef->version();
 
diff --git a/src/qml/qml/qqmlproxymetaobject.cpp b/src/qml/qml/qqmlproxymetaobject.cpp
index 21d3c7ed05..6f48146fa3 100644
--- a/src/qml/qml/qqmlproxymetaobject.cpp
+++ b/src/qml/qml/qqmlproxymetaobject.cpp
@@ -68,11 +68,8 @@ QQmlProxyMetaObject::~QQmlProxyMetaObject()
 QObject *QQmlProxyMetaObject::getProxy(int index)
 {
     if (!proxies) {
-        if (!proxies) {
-            proxies = new QObject*[metaObjects->count()];
-            ::memset(proxies, 0,
-                     sizeof(QObject *) * metaObjects->count());
-        }
+        proxies = new QObject *[metaObjects->count()];
+        ::memset(proxies, 0, sizeof(QObject *) * metaObjects->count());
     }
 
     if (!proxies[index]) {
@@ -112,6 +109,7 @@ int QQmlProxyMetaObject::metaCall(QObject *o, QMetaObject::Call c, int id, void
             const int globalPropertyOffset = metaObjects->at(ii).propertyOffset;
             if (id >= globalPropertyOffset) {
                 QObject *proxy = getProxy(ii);
+                Q_ASSERT(proxy);
                 const int localProxyOffset = proxy->metaObject()->propertyOffset();
                 const int localProxyId = id - globalPropertyOffset + localProxyOffset;
 
@@ -129,7 +127,7 @@ int QQmlProxyMetaObject::metaCall(QObject *o, QMetaObject::Call c, int id, void
                 const int globalMethodOffset = metaObjects->at(ii).methodOffset;
                 if (id >= globalMethodOffset) {
                     QObject *proxy = getProxy(ii);
-
+                    Q_ASSERT(proxy);
                     const int localMethodOffset = proxy->metaObject()->methodOffset();
                     const int localMethodId = id - globalMethodOffset + localMethodOffset;
 
diff --git a/src/qml/qml/qqmlscriptstring.cpp b/src/qml/qml/qqmlscriptstring.cpp
index 3230e69b6d..4df3a63785 100644
--- a/src/qml/qml/qqmlscriptstring.cpp
+++ b/src/qml/qml/qqmlscriptstring.cpp
@@ -220,3 +220,5 @@ bool QQmlScriptString::booleanLiteral(bool *ok) const
 
 QT_END_NAMESPACE
 
+#include "moc_qqmlscriptstring.cpp"
+
diff --git a/src/qml/qml/qqmltype.cpp b/src/qml/qml/qqmltype.cpp
index 811ff668c6..c283f7c718 100644
--- a/src/qml/qml/qqmltype.cpp
+++ b/src/qml/qml/qqmltype.cpp
@@ -216,16 +216,15 @@ void QQmlTypePrivate::init() const
         return;
     }
 
-    auto setupExtendedMetaObject = [&](
-            const QMetaObject *extMetaObject,
-            QObject *(*extFunc)(QObject *)) {
-
+    auto setupExtendedMetaObject = [&](const QMetaObject *extMetaObject,
+                                       QObject *(*extFunc)(QObject *)) {
         if (!extMetaObject)
             return;
 
         // XXX - very inefficient
         QMetaObjectBuilder builder;
-        QQmlMetaType::clone(builder, extMetaObject, extMetaObject, extMetaObject);
+        QQmlMetaType::clone(builder, extMetaObject, extMetaObject, extMetaObject,
+                            extFunc ? QQmlMetaType::CloneAll : QQmlMetaType::CloneEnumsOnly);
         builder.setFlags(MetaObjectFlag::DynamicMetaObject);
         QMetaObject *mmo = builder.toMetaObject();
         mmo->d.superdata = mo;
diff --git a/src/qml/qml/qqmltypeloadernetworkreplyproxy.cpp b/src/qml/qml/qqmltypeloadernetworkreplyproxy.cpp
index af97643163..bcc5306cf8 100644
--- a/src/qml/qml/qqmltypeloadernetworkreplyproxy.cpp
+++ b/src/qml/qml/qqmltypeloadernetworkreplyproxy.cpp
@@ -72,3 +72,5 @@ void QQmlTypeLoaderNetworkReplyProxy::manualFinished(QNetworkReply *reply)
 }
 
 QT_END_NAMESPACE
+
+#include "moc_qqmltypeloadernetworkreplyproxy_p.cpp"
diff --git a/src/qml/qml/qqmlvaluetypewrapper.cpp b/src/qml/qml/qqmlvaluetypewrapper.cpp
index c2bbd7f498..2cba0375e7 100644
--- a/src/qml/qml/qqmlvaluetypewrapper.cpp
+++ b/src/qml/qml/qqmlvaluetypewrapper.cpp
@@ -281,10 +281,27 @@ PropertyAttributes QQmlValueTypeWrapper::virtualGetOwnProperty(const Managed *m,
 {
     if (id.isString()) {
         const QQmlValueTypeWrapper *r = static_cast<const QQmlValueTypeWrapper *>(m);
-        QQmlPropertyData result = r->dataForPropertyKey(id);
-        if (p && result.isValid())
-            p->value = getGadgetProperty(r->engine(), r->d(), result.propType(), result.coreIndex(), result.isFunction(), result.isEnum());
-        return result.isValid() ? Attr_Data : Attr_Invalid;
+        Q_ASSERT(r);
+
+        const QQmlPropertyData result = r->dataForPropertyKey(id);
+        if (!result.isValid())
+            return Attr_Invalid; // Property doesn't exist. Object shouldn't meddle with it.
+
+        if (!p)
+            return Attr_Data; // Property exists, but we're not interested in the value
+
+        const QQmlValueTypeReference *ref = r->as<const QQmlValueTypeReference>();
+        if (!ref || ref->readReferenceValue()) {
+            // Property exists, and we can retrieve it
+            p->value = getGadgetProperty(
+                        r->engine(), r->d(), result.propType(), result.coreIndex(),
+                        result.isFunction(), result.isEnum());
+        } else {
+            // Property exists, but we can't retrieve it. Make it undefined.
+            p->value = Encode::undefined();
+        }
+
+        return Attr_Data;
     }
 
     return QV4::Object::virtualGetOwnProperty(m, id, p);
diff --git a/src/qml/types/qqmlconnections.cpp b/src/qml/types/qqmlconnections.cpp
index 8e45350982..f13a39946d 100644
--- a/src/qml/types/qqmlconnections.cpp
+++ b/src/qml/types/qqmlconnections.cpp
@@ -130,6 +130,12 @@ public:
     }
     \endqml
 
+    \note For backwards compatibility you can also specify the signal handlers
+    without \c{function}, like you would specify them directly in the target
+    object. This is not recommended. If you specify one signal handler this way,
+    then all signal handlers specified as \c{function} in the same Connections
+    object are ignored.
+
     \sa {Qt QML}
 */
 QQmlConnections::QQmlConnections(QObject *parent) :
diff --git a/src/qml/util/qqmlpropertymap.cpp b/src/qml/util/qqmlpropertymap.cpp
index 2bf8ab0190..23bf1b307c 100644
--- a/src/qml/util/qqmlpropertymap.cpp
+++ b/src/qml/util/qqmlpropertymap.cpp
@@ -409,3 +409,5 @@ QQmlPropertyMap::QQmlPropertyMap(const QMetaObject *staticMetaObject, QObject *p
 */
 
 QT_END_NAMESPACE
+
+#include "moc_qqmlpropertymap.cpp"