Merge remote-tracking branch 'origin/dev' into wip/cmake

 Conflicts:
        dependencies.yaml

Change-Id: Ie3e9dc62031a85e5e81cbdf04694b95159d49fca

61 files changed, 1951 insertions, 445 deletions

diff --git a/src/qml/common/qv4compileddata_p.h b/src/qml/common/qv4compileddata_p.h
index 3e5e4ae11e..1480df2817 100644
--- a/src/qml/common/qv4compileddata_p.h
+++ b/src/qml/common/qv4compileddata_p.h
@@ -76,7 +76,7 @@ QT_BEGIN_NAMESPACE
 // Also change the comment behind the number to describe the latest change. This has the added
 // benefit that if another patch changes the version too, it will result in a merge conflict, and
 // not get removed silently.
-#define QV4_DATA_STRUCTURE_VERSION 0x27 // resolved merge
+#define QV4_DATA_STRUCTURE_VERSION 0x28// support inline components
 
 class QIODevice;
 class QQmlTypeNameCache;
@@ -113,6 +113,7 @@ struct TableIterator
     int index;
 
     const ItemType *operator->() { return (container->*IndexedGetter)(index); }
+    ItemType operator*() {return *operator->();}
     void operator++() { ++index; }
     bool operator==(const TableIterator &rhs) const { return index == rhs.index; }
     bool operator!=(const TableIterator &rhs) const { return index != rhs.index; }
@@ -573,6 +574,15 @@ struct Binding
 
 static_assert(sizeof(Binding) == 24, "Binding structure needs to have the expected size to be binary compatible on disk when generated by host compiler and loaded by target");
 
+struct InlineComponent
+{
+    quint32_le objectIndex;
+    quint32_le nameIndex;
+    Location location;
+};
+
+static_assert(sizeof(InlineComponent) == 12, "InlineComponent structure needs to have the expected size to be binary compatible on disk when generated by host compiler and loaded by target");
+
 struct EnumValue
 {
     quint32_le nameIndex;
@@ -697,7 +707,9 @@ struct Object
         NoFlag = 0x0,
         IsComponent = 0x1, // object was identified to be an explicit or implicit component boundary
         HasDeferredBindings = 0x2, // any of the bindings are deferred
-        HasCustomParserBindings = 0x4
+        HasCustomParserBindings = 0x4,
+        IsInlineComponentRoot = 0x8,
+        InPartOfInlineComponent = 0x10
     };
 
     // Depending on the use, this may be the type name to instantiate before instantiating this
@@ -727,12 +739,15 @@ struct Object
     quint32_le offsetToNamedObjectsInComponent;
     Location location;
     Location locationOfIdProperty;
+    quint32_le offsetToInlineComponents;
+    quint16_le nInlineComponents;
 //    Function[]
 //    Property[]
 //    Signal[]
 //    Binding[]
+//    InlineComponent[]
 
-    static int calculateSizeExcludingSignalsAndEnums(int nFunctions, int nProperties, int nAliases, int nEnums, int nSignals, int nBindings, int nNamedObjectsInComponent)
+    static int calculateSizeExcludingSignalsAndEnums(int nFunctions, int nProperties, int nAliases, int nEnums, int nSignals, int nBindings, int nNamedObjectsInComponent, int nInlineComponents)
     {
         return ( sizeof(Object)
                  + nFunctions * sizeof(quint32)
@@ -742,6 +757,7 @@ struct Object
                  + nSignals * sizeof(quint32)
                  + nBindings * sizeof(Binding)
                  + nNamedObjectsInComponent * sizeof(int)
+                 + nInlineComponents * sizeof(InlineComponent)
                  + 0x7
                ) & ~0x7;
     }
@@ -780,11 +796,21 @@ struct Object
         return reinterpret_cast<const Signal*>(reinterpret_cast<const char*>(this) + offset);
     }
 
+    const InlineComponent *inlineComponentAt(int idx) const
+    {
+        return inlineComponentTable() + idx;
+    }
+
     const quint32_le *namedObjectsInComponentTable() const
     {
         return reinterpret_cast<const quint32_le*>(reinterpret_cast<const char *>(this) + offsetToNamedObjectsInComponent);
     }
 
+    const InlineComponent *inlineComponentTable() const
+    {
+        return reinterpret_cast<const InlineComponent*>(reinterpret_cast<const char *>(this) + offsetToInlineComponents);
+    }
+
     // --- QQmlPropertyCacheCreator interface
     int propertyCount() const { return nProperties; }
     int aliasCount() const { return nAliases; }
@@ -809,17 +835,22 @@ struct Object
     SignalIterator signalsBegin() const { return SignalIterator(this, 0); }
     SignalIterator signalsEnd() const { return SignalIterator(this, nSignals); }
 
+    typedef TableIterator<InlineComponent, Object, &Object::inlineComponentAt> InlineComponentIterator;
+    InlineComponentIterator inlineComponentsBegin() const {return InlineComponentIterator(this, 0);}
+    InlineComponentIterator inlineComponentsEnd() const {return InlineComponentIterator(this, nInlineComponents);}
+
     int namedObjectsInComponentCount() const { return nNamedObjectsInComponent; }
     // ---
 };
-static_assert(sizeof(Object) == 68, "Object structure needs to have the expected size to be binary compatible on disk when generated by host compiler and loaded by target");
+static_assert(sizeof(Object) == 76, "Object structure needs to have the expected size to be binary compatible on disk when generated by host compiler and loaded by target");
 
 struct Import
 {
     enum ImportType : unsigned int {
         ImportLibrary = 0x1,
         ImportFile = 0x2,
-        ImportScript = 0x3
+        ImportScript = 0x3,
+        ImportInlineComponent = 0x4
     };
     quint32_le type;
 
@@ -1047,7 +1078,7 @@ struct TypeReferenceMap : QHash<int, TypeReference>
         }
 
         auto prop = obj->propertiesBegin();
-        auto propEnd = obj->propertiesEnd();
+        auto const propEnd = obj->propertiesEnd();
         for ( ; prop != propEnd; ++prop) {
             if (!prop->isBuiltinType) {
                 TypeReference &r = this->add(prop->builtinTypeOrTypeNameIndex, prop->location);
@@ -1056,11 +1087,17 @@ struct TypeReferenceMap : QHash<int, TypeReference>
         }
 
         auto binding = obj->bindingsBegin();
-        auto bindingEnd = obj->bindingsEnd();
+        auto const bindingEnd = obj->bindingsEnd();
         for ( ; binding != bindingEnd; ++binding) {
             if (binding->type == QV4::CompiledData::Binding::Type_AttachedProperty)
                 this->add(binding->propertyNameIndex, binding->location);
         }
+
+        auto ic = obj->inlineComponentsBegin();
+        auto const icEnd = obj->inlineComponentsEnd();
+        for (; ic != icEnd; ++ic) {
+            this->add(ic->nameIndex, ic->location);
+        }
     }
 
     template <typename Iterator>
diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 9623d2ed58..811f88cb73 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -161,6 +161,7 @@ void Object::init(QQmlJS::MemoryPool *pool, int typeNameIndex, int idIndex, cons
     bindings = pool->New<PoolList<Binding> >();
     functions = pool->New<PoolList<Function> >();
     functionsAndExpressions = pool->New<PoolList<CompiledFunctionOrExpression> >();
+    inlineComponents = pool->New<PoolList<InlineComponent>>();
     declarationsOverride = nullptr;
 }
 
@@ -281,6 +282,11 @@ void Object::appendFunction(QmlIR::Function *f)
     target->functions->append(f);
 }
 
+void Object::appendInlineComponent(InlineComponent *ic)
+{
+    inlineComponents->append(ic);
+}
+
 QString Object::appendBinding(Binding *b, bool isListBinding)
 {
     const bool bindingToDefaultProperty = (b->propertyNameIndex == quint32(0));
@@ -503,6 +509,33 @@ bool IRBuilder::visit(QQmlJS::AST::UiObjectDefinition *node)
     return false;
 }
 
+bool IRBuilder::visit(QQmlJS::AST::UiInlineComponent *ast)
+{
+    int idx = -1;
+    if (insideInlineComponent) {
+        recordError(ast->firstSourceLocation(), QLatin1String("Nested inline components are not supported"));
+        return false;
+    }
+    {
+        QScopedValueRollback<bool> rollBack {insideInlineComponent, true};
+        if (!defineQMLObject(&idx, ast->component))
+            return false;
+    }
+    Q_ASSERT(idx > 0);
+    Object* definedObject = _objects.at(idx);
+    definedObject->flags |= QV4::CompiledData::Object::IsInlineComponentRoot;
+    definedObject->flags |= QV4::CompiledData::Object::InPartOfInlineComponent;
+    definedObject->isInlineComponent = true;
+    auto inlineComponent = New<InlineComponent>();
+    inlineComponent->nameIndex = registerString(ast->name.toString());
+    inlineComponent->objectIndex = idx;
+    auto location = ast->firstSourceLocation();
+    inlineComponent->location.line = location.startLine;
+    inlineComponent->location.column = location.startColumn;
+    _object->appendInlineComponent(inlineComponent);
+    return false;
+}
+
 bool IRBuilder::visit(QQmlJS::AST::UiObjectBinding *node)
 {
     int idx = 0;
@@ -597,12 +630,16 @@ bool IRBuilder::defineQMLObject(int *objectIndex, QQmlJS::AST::UiQualifiedId *qu
     }
 
     Object *obj = New<Object>();
+
     _objects.append(obj);
     *objectIndex = _objects.size() - 1;
     qSwap(_object, obj);
 
     _object->init(pool, registerString(asString(qualifiedTypeNameId)), emptyStringIndex, location);
     _object->declarationsOverride = declarationsOverride;
+    if (insideInlineComponent) {
+        _object->flags |= QV4::CompiledData::Object::InPartOfInlineComponent;
+    }
 
     // A new object is also a boundary for property declarations.
     Property *declaration = nullptr;
@@ -1553,7 +1590,7 @@ void QmlUnitGenerator::generate(Document &output, const QV4::CompiledData::Depen
     uint nextOffset = objectOffset + objectOffsetTableSize;
     for (Object *o : qAsConst(output.objects)) {
         objectOffsets.insert(o, nextOffset);
-        nextOffset += QV4::CompiledData::Object::calculateSizeExcludingSignalsAndEnums(o->functionCount(), o->propertyCount(), o->aliasCount(), o->enumCount(), o->signalCount(), o->bindingCount(), o->namedObjectsInComponent.size());
+        nextOffset += QV4::CompiledData::Object::calculateSizeExcludingSignalsAndEnums(o->functionCount(), o->propertyCount(), o->aliasCount(), o->enumCount(), o->signalCount(), o->bindingCount(), o->namedObjectsInComponent.size(), o->inlineComponentCount());
 
         int signalTableSize = 0;
         for (const Signal *s = o->firstSignal(); s; s = s->next)
@@ -1632,6 +1669,10 @@ void QmlUnitGenerator::generate(Document &output, const QV4::CompiledData::Depen
         objectToWrite->offsetToNamedObjectsInComponent = nextOffset;
         nextOffset += objectToWrite->nNamedObjectsInComponent * sizeof(quint32);
 
+        objectToWrite->nInlineComponents = o->inlineComponentCount();
+        objectToWrite->offsetToInlineComponents = nextOffset;
+        nextOffset += objectToWrite->nInlineComponents * sizeof (QV4::CompiledData::InlineComponent);
+
         quint32_le *functionsTable = reinterpret_cast<quint32_le *>(objectPtr + objectToWrite->offsetToFunctions);
         for (const Function *f = o->firstFunction(); f; f = f->next)
             *functionsTable++ = o->runtimeFunctionIndices.at(f->index);
@@ -1703,6 +1744,14 @@ void QmlUnitGenerator::generate(Document &output, const QV4::CompiledData::Depen
         for (int i = 0; i < o->namedObjectsInComponent.size(); ++i) {
             *namedObjectInComponentPtr++ = o->namedObjectsInComponent.at(i);
         }
+
+        char *inlineComponentPtr = objectPtr + objectToWrite->offsetToInlineComponents;
+        for (auto it = o->inlineComponentsBegin(); it != o->inlineComponentsEnd(); ++it) {
+            const InlineComponent *ic = it.ptr;
+            QV4::CompiledData::InlineComponent *icToWrite = reinterpret_cast<QV4::CompiledData::InlineComponent*>(inlineComponentPtr);
+            *icToWrite = *ic;
+            inlineComponentPtr += sizeof(QV4::CompiledData::InlineComponent);
+        }
     }
 
     if (!output.javaScriptCompilationUnit.data) {
@@ -1850,12 +1899,14 @@ bool JSCodeGen::generateCodeForComponents(const QVector<quint32> &componentRoots
 bool JSCodeGen::compileComponent(int contextObject)
 {
     const QmlIR::Object *obj = document->objects.at(contextObject);
-    if (obj->flags & QV4::CompiledData::Object::IsComponent) {
+    if (obj->flags & QV4::CompiledData::Object::IsComponent && !obj->isInlineComponent) {
         Q_ASSERT(obj->bindingCount() == 1);
         const QV4::CompiledData::Binding *componentBinding = obj->firstBinding();
         Q_ASSERT(componentBinding->type == QV4::CompiledData::Binding::Type_Object);
         contextObject = componentBinding->value.objectIndex;
     }
+    for (auto it = obj->inlineComponentsBegin(); it != obj->inlineComponentsEnd(); ++it)
+        compileComponent(it->objectIndex);
 
     return compileJavaScriptCodeInObjectsRecursively(contextObject, contextObject);
 }
@@ -1863,7 +1914,7 @@ bool JSCodeGen::compileComponent(int contextObject)
 bool JSCodeGen::compileJavaScriptCodeInObjectsRecursively(int objectIndex, int scopeObjectIndex)
 {
     QmlIR::Object *object = document->objects.at(objectIndex);
-    if (object->flags & QV4::CompiledData::Object::IsComponent)
+    if (object->flags & QV4::CompiledData::Object::IsComponent && !object->isInlineComponent)
         return true;
 
     if (object->functionsAndExpressions->count > 0) {
diff --git a/src/qml/compiler/qqmlirbuilder_p.h b/src/qml/compiler/qqmlirbuilder_p.h
index ab0ddf6ef8..d4f2eb8dd4 100644
--- a/src/qml/compiler/qqmlirbuilder_p.h
+++ b/src/qml/compiler/qqmlirbuilder_p.h
@@ -275,6 +275,11 @@ struct Binding : public QV4::CompiledData::Binding
     Binding *next;
 };
 
+struct InlineComponent : public QV4::CompiledData::InlineComponent
+{
+    InlineComponent *next;
+};
+
 struct Alias : public QV4::CompiledData::Alias
 {
     Alias *next;
@@ -316,6 +321,7 @@ public:
     int id;
     int indexOfDefaultPropertyOrAlias;
     bool defaultPropertyIsAlias;
+    bool isInlineComponent = false;
     quint32 flags;
 
     QV4::CompiledData::Location location;
@@ -333,6 +339,8 @@ public:
     int bindingCount() const { return bindings->count; }
     const Function *firstFunction() const { return functions->first; }
     int functionCount() const { return functions->count; }
+    const InlineComponent *inlineComponent() const { return inlineComponents->first; }
+    int inlineComponentCount() const { return inlineComponents->count; }
 
     PoolList<Binding>::Iterator bindingsBegin() const { return bindings->begin(); }
     PoolList<Binding>::Iterator bindingsEnd() const { return bindings->end(); }
@@ -346,6 +354,8 @@ public:
     PoolList<Signal>::Iterator signalsEnd() const { return qmlSignals->end(); }
     PoolList<Function>::Iterator functionsBegin() const { return functions->begin(); }
     PoolList<Function>::Iterator functionsEnd() const { return functions->end(); }
+    PoolList<InlineComponent>::Iterator inlineComponentsBegin() const { return inlineComponents->begin(); }
+    PoolList<InlineComponent>::Iterator inlineComponentsEnd() const { return inlineComponents->end(); }
 
     // If set, then declarations for this object (and init bindings for these) should go into the
     // specified object. Used for declarations inside group properties.
@@ -358,6 +368,7 @@ public:
     QString appendProperty(Property *prop, const QString &propertyName, bool isDefaultProperty, const QQmlJS::AST::SourceLocation &defaultToken, QQmlJS::AST::SourceLocation *errorLocation);
     QString appendAlias(Alias *prop, const QString &aliasName, bool isDefaultProperty, const QQmlJS::AST::SourceLocation &defaultToken, QQmlJS::AST::SourceLocation *errorLocation);
     void appendFunction(QmlIR::Function *f);
+    void appendInlineComponent(InlineComponent *ic);
 
     QString appendBinding(Binding *b, bool isListBinding);
     Binding *findBinding(quint32 nameIndex) const;
@@ -381,6 +392,7 @@ private:
     PoolList<Signal> *qmlSignals;
     PoolList<Binding> *bindings;
     PoolList<Function> *functions;
+    PoolList<InlineComponent> *inlineComponents;
 };
 
 struct Q_QMLCOMPILER_PRIVATE_EXPORT Pragma
@@ -409,6 +421,9 @@ struct Q_QMLCOMPILER_PRIVATE_EXPORT Document
 
     int registerString(const QString &str) { return jsGenerator.registerString(str); }
     QString stringAt(int index) const { return jsGenerator.stringForIndex(index); }
+
+    int objectCount() const {return objects.size();}
+    Object* objectAt(int i) const {return objects.at(i);}
 };
 
 class Q_QMLCOMPILER_PRIVATE_EXPORT ScriptDirectivesCollector : public QQmlJS::Directives
@@ -449,6 +464,7 @@ public:
     bool visit(QQmlJS::AST::UiArrayBinding *ast) override;
     bool visit(QQmlJS::AST::UiObjectBinding *ast) override;
     bool visit(QQmlJS::AST::UiObjectDefinition *ast) override;
+    bool visit(QQmlJS::AST::UiInlineComponent *ast) override;
     bool visit(QQmlJS::AST::UiEnumDeclaration *ast) override;
     bool visit(QQmlJS::AST::UiPublicMember *ast) override;
     bool visit(QQmlJS::AST::UiScriptBinding *ast) override;
@@ -527,6 +543,8 @@ public:
     QQmlJS::MemoryPool *pool;
     QString sourceCode;
     QV4::Compiler::JSUnitGenerator *jsGenerator;
+
+    bool insideInlineComponent = false;
 };
 
 struct Q_QMLCOMPILER_PRIVATE_EXPORT QmlUnitGenerator
diff --git a/src/qml/debugger/qqmldebug.cpp b/src/qml/debugger/qqmldebug.cpp
index 6532576e03..58b8ea2c4f 100644
--- a/src/qml/debugger/qqmldebug.cpp
+++ b/src/qml/debugger/qqmldebug.cpp
@@ -65,8 +65,7 @@ QQmlDebuggingEnabler::QQmlDebuggingEnabler(bool printWarning)
  */
 QStringList QQmlDebuggingEnabler::debuggerServices()
 {
-    return QStringList() << QV4DebugService::s_key << QQmlEngineDebugService::s_key
-                         << QDebugMessageService::s_key;
+    return {QV4DebugService::s_key, QQmlEngineDebugService::s_key, QDebugMessageService::s_key};
 }
 
 /*!
@@ -76,7 +75,7 @@ QStringList QQmlDebuggingEnabler::debuggerServices()
  */
 QStringList QQmlDebuggingEnabler::inspectorServices()
 {
-    return QStringList() << QQmlInspectorService::s_key;
+    return {QQmlInspectorService::s_key};
 }
 
 /*!
@@ -87,8 +86,7 @@ QStringList QQmlDebuggingEnabler::inspectorServices()
  */
 QStringList QQmlDebuggingEnabler::profilerServices()
 {
-    return QStringList() << QQmlProfilerService::s_key << QQmlEngineControlService::s_key
-                         << QDebugMessageService::s_key;
+    return {QQmlProfilerService::s_key, QQmlEngineControlService::s_key, QDebugMessageService::s_key};
 }
 
 /*!
@@ -99,7 +97,7 @@ QStringList QQmlDebuggingEnabler::profilerServices()
  */
 QStringList QQmlDebuggingEnabler::nativeDebuggerServices()
 {
-    return QStringList() << QQmlNativeDebugService::s_key;
+    return {QQmlNativeDebugService::s_key};
 }
 
 /*!
diff --git a/src/qml/inlinecomponentutils_p.h b/src/qml/inlinecomponentutils_p.h
new file mode 100644
index 0000000000..99b28349cd
--- /dev/null
+++ b/src/qml/inlinecomponentutils_p.h
@@ -0,0 +1,161 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#ifndef INLINECOMPONENTUTILS_P_H
+#define INLINECOMPONENTUTILS_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qv4compileddata_p.h>
+#include <private/qv4executablecompilationunit_p.h>
+
+namespace icutils {
+struct Node {
+    Node() = default;
+    Node(const Node &) = default;
+    Node(Node &&) = default;
+    Node& operator=(Node const &) = default;
+    Node& operator=(Node &&) = default;
+    bool operator==(Node const &other) const {return index == other.index;}
+
+    Node(std::vector<QV4::CompiledData::InlineComponent>::size_type s) {
+        index = quint32(s);
+        temporaryMark = 0;
+        permanentMark = 0;
+    }
+
+    union {
+        quint32_le_bitfield<0, 30> index;
+        quint32_le_bitfield<30, 1> temporaryMark;
+        quint32_le_bitfield<31, 1> permanentMark;
+    };
+};
+
+using AdjacencyList = std::vector<std::vector<Node*>>;
+
+template<typename ObjectContainer, typename InlineComponent>
+void fillAdjacencyListForInlineComponents(ObjectContainer *objectContainer, AdjacencyList &adjacencyList, std::vector<Node> &nodes, const std::vector<InlineComponent> &allICs) {
+    using CompiledObject = typename ObjectContainer::CompiledObject;
+    // add an edge from A to B if A and B are inline components with the same containing type
+    // and A inherits from B (ignore indirect chains through external types for now)
+    // or if A instantiates B
+    for (typename std::vector<InlineComponent>::size_type i = 0; i < allICs.size(); ++i) {
+        const auto& ic = allICs[i];
+        const CompiledObject *obj = objectContainer->objectAt(ic.objectIndex);
+        QV4::ResolvedTypeReference *currentICTypeRef = objectContainer->resolvedType(ic.nameIndex);
+        auto createEdgeFromTypeRef = [&](QV4::ResolvedTypeReference *targetTypeRef) {
+            if (targetTypeRef && targetTypeRef->type.isInlineComponentType()) {
+                if (targetTypeRef->type.containingType() == currentICTypeRef->type.containingType()) {
+                    auto icIt = std::find_if(allICs.cbegin(), allICs.cend(), [&](const QV4::CompiledData::InlineComponent &icSearched){
+                        return int(icSearched.objectIndex) == targetTypeRef->type.inlineComponentObjectId();
+                    });
+                    Q_ASSERT(icIt != allICs.cend());
+                    Node& target = nodes[i];
+                    adjacencyList[std::distance(allICs.cbegin(), icIt)].push_back(&target);
+                }
+            }
+        };
+        if (obj->inheritedTypeNameIndex != 0) {
+            QV4::ResolvedTypeReference *parentTypeRef = objectContainer->resolvedType(obj->inheritedTypeNameIndex);
+            createEdgeFromTypeRef(parentTypeRef);
+
+        }
+        auto referencedInICObjectIndex = ic.objectIndex + 1;
+        while (int(referencedInICObjectIndex) < objectContainer->objectCount()) {
+            auto potentiallyReferencedInICObject = objectContainer->objectAt(referencedInICObjectIndex);
+            bool stillInIC = !(potentiallyReferencedInICObject-> flags & QV4::CompiledData::Object::IsInlineComponentRoot)
+                    && (potentiallyReferencedInICObject-> flags & QV4::CompiledData::Object::InPartOfInlineComponent);
+            if (!stillInIC)
+                break;
+            createEdgeFromTypeRef(objectContainer->resolvedType(potentiallyReferencedInICObject->inheritedTypeNameIndex));
+            ++referencedInICObjectIndex;
+        }
+    }
+};
+
+inline void topoVisit(Node *node, AdjacencyList &adjacencyList, bool &hasCycle, std::vector<Node> &nodesSorted) {
+    if (node->permanentMark)
+        return;
+    if (node->temporaryMark) {
+        hasCycle = true;
+        return;
+    }
+    node->temporaryMark = 1;
+
+    auto const &edges = adjacencyList[node->index];
+    for (auto edgeTarget =edges.begin(); edgeTarget != edges.end(); ++edgeTarget) {
+        topoVisit(*edgeTarget, adjacencyList, hasCycle, nodesSorted);
+    }
+
+    node->temporaryMark = 0;
+    node->permanentMark = 1;
+    nodesSorted.push_back(*node);
+};
+
+// Use DFS based topological sorting (https://en.wikipedia.org/wiki/Topological_sorting)
+inline std::vector<Node> topoSort(std::vector<Node> &nodes, AdjacencyList &adjacencyList, bool &hasCycle) {
+    std::vector<Node> nodesSorted;
+    nodesSorted.reserve(nodes.size());
+
+    hasCycle = false;
+    auto currentNodeIt = std::find_if(nodes.begin(), nodes.end(), [](const Node& node) {
+        return node.permanentMark == 0;
+    });
+    // Do a topological sort of all inline components
+    // afterwards, nodesSorted contains the nodes for the inline components in reverse topological order
+    while (currentNodeIt != nodes.end() && !hasCycle) {
+        Node& currentNode = *currentNodeIt;
+        topoVisit(&currentNode, adjacencyList, hasCycle, nodesSorted);
+        currentNodeIt = std::find_if(nodes.begin(), nodes.end(), [](const Node& node) {
+            return node.permanentMark == 0;
+        });
+    }
+    return nodesSorted;
+}
+}
+
+#endif // INLINECOMPONENTUTILS_P_H
diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index 065fbc1c0a..6946a64d11 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -71,11 +71,6 @@
 #include <private/qqmlglobal_p.h>
 #include <qqmlengine.h>
 
-#undef Q_D
-#undef Q_Q
-#define Q_D(blah)
-#define Q_Q(blah)
-
 Q_DECLARE_METATYPE(QList<int>)
 
 /*!
@@ -257,7 +252,7 @@ Q_DECLARE_METATYPE(QList<int>)
     \l installExtensions().
 
     \value TranslationExtension Indicates that translation functions (\c qsTr(),
-        for example) should be installed.
+        for example) should be installed. This also installs the Qt.uiLanguage property.
 
     \value ConsoleExtension Indicates that console functions (\c console.log(),
         for example) should be installed.
@@ -692,7 +687,6 @@ QJSValue QJSEngine::newArray(uint length)
 */
 QJSValue QJSEngine::newQObject(QObject *object)
 {
-    Q_D(QJSEngine);
     QV4::ExecutionEngine *v4 = m_v4Engine;
     QV4::Scope scope(v4);
     if (object) {
@@ -719,7 +713,6 @@ QJSValue QJSEngine::newQObject(QObject *object)
 */
 
 QJSValue QJSEngine::newQMetaObject(const QMetaObject* metaObject) {
-    Q_D(QJSEngine);
     QV4::ExecutionEngine *v4 = m_v4Engine;
     QV4::Scope scope(v4);
     QV4::ScopedValue v(scope, QV4::QMetaObjectWrapper::create(v4, metaObject));
@@ -1004,6 +997,35 @@ void QJSEngine::throwError(QJSValue::ErrorType errorType, const QString &message
     m_v4Engine->throwError(e);
 }
 
+/*!
+  \property QJSEngine::uiLanguage
+  \brief the language to be used for translating user interface strings
+  \since 5.15
+
+  This property holds the name of the language to be used for user interface
+  string translations. It is exposed for reading and writing as \c{Qt.uiLanguage} when
+  the QJSEngine::TranslationExtension is installed on the engine. It is always exposed
+  in instances of QQmlEngine.
+
+  You can set the value freely and use it in bindings. It is recommended to set it
+  after installing translators in your application. By convention, an empty string
+  means no translation from the language used in the source code is intended to occur.
+*/
+void QJSEngine::setUiLanguage(const QString &language)
+{
+    Q_D(QJSEngine);
+    if (language == d->uiLanguage)
+        return;
+    d->uiLanguage = language;
+    emit uiLanguageChanged();
+}
+
+QString QJSEngine::uiLanguage() const
+{
+    Q_D(const QJSEngine);
+    return d->uiLanguage;
+}
+
 QJSEnginePrivate *QJSEnginePrivate::get(QV4::ExecutionEngine *e)
 {
     return e->jsEngine()->d_func();
diff --git a/src/qml/jsapi/qjsengine.h b/src/qml/jsapi/qjsengine.h
index 31a4d68baa..31229e1f20 100644
--- a/src/qml/jsapi/qjsengine.h
+++ b/src/qml/jsapi/qjsengine.h
@@ -60,6 +60,7 @@ class Q_QML_EXPORT QJSEngine
     : public QObject
 {
     Q_OBJECT
+    Q_PROPERTY(QString uiLanguage READ uiLanguage WRITE setUiLanguage NOTIFY uiLanguageChanged)
 public:
     QJSEngine();
     explicit QJSEngine(QObject *parent);
@@ -121,6 +122,12 @@ public:
     void throwError(const QString &message);
     void throwError(QJSValue::ErrorType errorType, const QString &message = QString());
 
+    QString uiLanguage() const;
+    void setUiLanguage(const QString &language);
+
+Q_SIGNALS:
+    void uiLanguageChanged();
+
 private:
     QJSValue create(int type, const void *ptr);
 
diff --git a/src/qml/jsapi/qjsengine_p.h b/src/qml/jsapi/qjsengine_p.h
index 164a70d000..7866a5bdda 100644
--- a/src/qml/jsapi/qjsengine_p.h
+++ b/src/qml/jsapi/qjsengine_p.h
@@ -107,6 +107,7 @@ public:
     // Shared by QQmlEngine
     mutable QRecursiveMutex mutex;
 
+    QString uiLanguage;
 
     // These methods may be called from the QML loader thread
     inline QQmlPropertyCache *cache(QObject *obj, int minorVersion = -1);
diff --git a/src/qml/jsapi/qjsvalue.cpp b/src/qml/jsapi/qjsvalue.cpp
index c2957dd294..b40bc1f18b 100644
--- a/src/qml/jsapi/qjsvalue.cpp
+++ b/src/qml/jsapi/qjsvalue.cpp
@@ -314,7 +314,7 @@ bool QJSValue::isBool() const
     if (val)
         return val->isBoolean();
     QVariant *variant = QJSValuePrivate::getVariant(this);
-    return variant && variant->type() == QVariant::Bool;
+    return variant && variant->userType() == QMetaType::Bool;
 }
 
 /*!
@@ -520,9 +520,9 @@ QString QJSValue::toString() const
     if (!val) {
         QVariant *variant = QJSValuePrivate::getVariant(this);
         Q_ASSERT(variant);
-        if (variant->type() == QVariant::Map)
+        if (variant->userType() == QMetaType::QVariantMap)
             return QStringLiteral("[object Object]");
-        else if (variant->type() == QVariant::List) {
+        else if (variant->userType() == QMetaType::QVariantList) {
             const QVariantList list = variant->toList();
             QString result;
             for (int i = 0; i < list.count(); ++i) {
@@ -558,7 +558,7 @@ double QJSValue::toNumber() const
         QVariant *variant = QJSValuePrivate::getVariant(this);
         Q_ASSERT(variant);
 
-        if (variant->type() == QVariant::String)
+        if (variant->userType() == QMetaType::QString)
             return RuntimeHelpers::stringToNumber(variant->toString());
         else if (variant->canConvert<double>())
             return variant->value<double>();
@@ -1040,7 +1040,7 @@ bool QJSValue::equals(const QJSValue& other) const
         Q_ASSERT(variant);
         if (!ov)
             return *variant == *QJSValuePrivate::getVariant(&other);
-        if (variant->type() == QVariant::Map || variant->type() == QVariant::List)
+        if (variant->userType() == QMetaType::QVariantMap || variant->userType() == QMetaType::QVariantList)
             return false;
         return js_equal(variant->toString(), *ov);
         }
@@ -1083,7 +1083,7 @@ bool QJSValue::strictlyEquals(const QJSValue& other) const
         Q_ASSERT(variant);
         if (!ov)
             return *variant == *QJSValuePrivate::getVariant(&other);
-        if (variant->type() == QVariant::Map || variant->type() == QVariant::List)
+        if (variant->userType() == QMetaType::QVariantMap || variant->userType() == QMetaType::QVariantList)
             return false;
         if (String *s = ov->stringValue())
             return variant->toString() == s->toQString();
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 14eaa5bce8..86e178d568 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -1461,7 +1461,7 @@ static QVariant toVariant(QV4::ExecutionEngine *e, const QV4::Value &value, int
     if (const QV4::VariantObject *v = value.as<QV4::VariantObject>())
         return v->d()->data();
 
-    if (typeHint == QVariant::Bool)
+    if (typeHint == QMetaType::Bool)
         return QVariant(value.toBoolean());
 
     if (typeHint == QMetaType::QJsonValue)
@@ -1533,7 +1533,7 @@ static QVariant toVariant(QV4::ExecutionEngine *e, const QV4::Value &value, int
     if (String *s = value.stringValue()) {
         const QString &str = s->toQString();
         // QChars are stored as a strings
-        if (typeHint == QVariant::Char && str.size() == 1)
+        if (typeHint == QMetaType::QChar && str.size() == 1)
             return str.at(0);
         return str;
     }
@@ -1832,7 +1832,7 @@ QV4::ReturnedValue ExecutionEngine::metaTypeToJS(int type, const void *data)
     Q_ASSERT(data != nullptr);
 
     QVariant variant(type, data);
-    if (QMetaType::Type(variant.type()) == QMetaType::QVariant) {
+    if (QMetaType::Type(variant.userType()) == QMetaType::QVariant) {
         // unwrap it: this is tested in QJSEngine, and makes the most sense for
         // end-user code too.
         return variantToJS(this, *reinterpret_cast<const QVariant*>(data));
@@ -1949,11 +1949,12 @@ void ExecutionEngine::initQmlGlobalObject()
 void ExecutionEngine::initializeGlobal()
 {
     QV4::Scope scope(this);
-    QV4::GlobalExtensions::init(globalObject, QJSEngine::AllExtensions);
 
     QV4::ScopedObject qt(scope, memoryManager->allocate<QV4::QtObject>(qmlEngine()));
     globalObject->defineDefaultProperty(QStringLiteral("Qt"), qt);
 
+    QV4::GlobalExtensions::init(globalObject, QJSEngine::AllExtensions);
+
 #if QT_CONFIG(qml_locale)
     QQmlLocale::registerStringLocaleCompare(this);
     QQmlDateExtension::registerExtension(this);
diff --git a/src/qml/jsruntime/qv4executablecompilationunit.cpp b/src/qml/jsruntime/qv4executablecompilationunit.cpp
index b1e2879bba..fa4a1f1ce4 100644
--- a/src/qml/jsruntime/qv4executablecompilationunit.cpp
+++ b/src/qml/jsruntime/qv4executablecompilationunit.cpp
@@ -53,6 +53,7 @@
 #include <private/qv4compilationunitmapper_p.h>
 #include <private/qml_compile_hash_p.h>
 #include <private/qqmltypewrapper_p.h>
+#include <private/inlinecomponentutils_p.h>
 
 #include <QtQml/qqmlfile.h>
 #include <QtQml/qqmlpropertymap.h>
@@ -62,6 +63,7 @@
 #include <QtCore/qfileinfo.h>
 #include <QtCore/qscopeguard.h>
 #include <QtCore/qcryptographichash.h>
+#include <QtCore/QScopedValueRollback>
 
 #if defined(QML_COMPILE_HASH)
 #  ifdef Q_OS_LINUX
@@ -387,7 +389,7 @@ IdentifierHash ExecutableCompilationUnit::createNamedObjectsPerComponent(int com
     return *namedObjectsPerComponentCache.insert(componentObjectIndex, namedObjectCache);
 }
 
-void ExecutableCompilationUnit::finalizeCompositeType(QQmlEnginePrivate *qmlEngine, QQmlMetaType::CompositeMetaTypeIds typeIds)
+void ExecutableCompilationUnit::finalizeCompositeType(QQmlEnginePrivate *qmlEngine, CompositeMetaTypeIds typeIds)
 {
     this->qmlEngine = qmlEngine;
 
@@ -399,6 +401,7 @@ void ExecutableCompilationUnit::finalizeCompositeType(QQmlEnginePrivate *qmlEngi
         metaTypeId = typeIds.id;
         listMetaTypeId = typeIds.listId;
         qmlEngine->registerInternalCompositeType(this);
+
     } else {
         const QV4::CompiledData::Object *obj = objectAt(/*root object*/0);
         auto *typeRef = resolvedTypes.value(obj->inheritedTypeNameIndex);
@@ -413,29 +416,105 @@ void ExecutableCompilationUnit::finalizeCompositeType(QQmlEnginePrivate *qmlEngi
     }
 
     // Collect some data for instantiation later.
+    using namespace  icutils;
+    std::vector<QV4::CompiledData::InlineComponent> allICs {};
+    for (int i=0; i != objectCount(); ++i) {
+        const CompiledObject *obj = objectAt(i);
+        for (auto it = obj->inlineComponentsBegin(); it != obj->inlineComponentsEnd(); ++it) {
+            allICs.push_back(*it);
+        }
+    }
+    std::vector<Node> nodes;
+    nodes.resize(allICs.size());
+    std::iota(nodes.begin(), nodes.end(), 0);
+    AdjacencyList adjacencyList;
+    adjacencyList.resize(nodes.size());
+    fillAdjacencyListForInlineComponents(this, adjacencyList, nodes, allICs);
+    bool hasCycle = false;
+    auto nodesSorted = topoSort(nodes, adjacencyList, hasCycle);
+    Q_ASSERT(!hasCycle); // would have already been discovered by qqmlpropertycachcecreator
+
+    // We need to first iterate over all inline components, as the containing component might create instances of them
+    // and in that case we need to add its object count
+    for (auto nodeIt = nodesSorted.rbegin(); nodeIt != nodesSorted.rend(); ++nodeIt) {
+        const auto &ic = allICs.at(nodeIt->index);
+        int lastICRoot = ic.objectIndex;
+        for (int i = ic.objectIndex; i<objectCount(); ++i) {
+            const QV4::CompiledData::Object *obj = objectAt(i);
+            bool leftCurrentInlineComponent =
+                       (i != lastICRoot && obj->flags & QV4::CompiledData::Object::IsInlineComponentRoot)
+                    || !(obj->flags & QV4::CompiledData::Object::InPartOfInlineComponent);
+            if (leftCurrentInlineComponent)
+                break;
+            inlineComponentData[lastICRoot].totalBindingCount += obj->nBindings;
+
+            if (auto *typeRef = resolvedTypes.value(obj->inheritedTypeNameIndex)) {
+                if (typeRef->type.isValid() && typeRef->type.parserStatusCast() != -1)
+                    ++inlineComponentData[lastICRoot].totalParserStatusCount;
+
+                ++inlineComponentData[lastICRoot].totalObjectCount;
+                if (typeRef->compilationUnit) {
+                    // if the type is an inline component type, we have to extract the information from it
+                    // This requires that inline components are visited in the correct order
+                    auto icRoot = typeRef->compilationUnit->icRoot;
+                    if (typeRef->type.isInlineComponentType()) {
+                        icRoot = typeRef->type.inlineComponendId();
+                    }
+                    QScopedValueRollback<int> rollback {typeRef->compilationUnit->icRoot, icRoot};
+                    inlineComponentData[lastICRoot].totalBindingCount += typeRef->compilationUnit->totalBindingsCount();
+                    inlineComponentData[lastICRoot].totalParserStatusCount += typeRef->compilationUnit->totalParserStatusCount();
+                    inlineComponentData[lastICRoot].totalObjectCount += typeRef->compilationUnit->totalObjectCount();
+                }
+            }
+        }
+    }
     int bindingCount = 0;
     int parserStatusCount = 0;
     int objectCount = 0;
     for (quint32 i = 0, count = this->objectCount(); i < count; ++i) {
         const QV4::CompiledData::Object *obj = objectAt(i);
+        if (obj->flags & QV4::CompiledData::Object::InPartOfInlineComponent) {
+            continue;
+        }
         bindingCount += obj->nBindings;
         if (auto *typeRef = resolvedTypes.value(obj->inheritedTypeNameIndex)) {
-            if (typeRef->type.isValid()) {
-                if (typeRef->type.parserStatusCast() != -1)
-                    ++parserStatusCount;
-            }
+            if (typeRef->type.isValid() && typeRef->type.parserStatusCast() != -1)
+                ++parserStatusCount;
             ++objectCount;
             if (typeRef->compilationUnit) {
-                bindingCount += typeRef->compilationUnit->totalBindingsCount;
-                parserStatusCount += typeRef->compilationUnit->totalParserStatusCount;
-                objectCount += typeRef->compilationUnit->totalObjectCount;
+                auto icRoot = typeRef->compilationUnit->icRoot;
+                if (typeRef->type.isInlineComponentType()) {
+                    icRoot = typeRef->type.inlineComponendId();
+                }
+                QScopedValueRollback<int> rollback {typeRef->compilationUnit->icRoot, icRoot};
+                bindingCount += typeRef->compilationUnit->totalBindingsCount();
+                parserStatusCount += typeRef->compilationUnit->totalParserStatusCount();
+                objectCount += typeRef->compilationUnit->totalObjectCount();
             }
         }
     }
 
-    totalBindingsCount = bindingCount;
-    totalParserStatusCount = parserStatusCount;
-    totalObjectCount = objectCount;
+    m_totalBindingsCount = bindingCount;
+    m_totalParserStatusCount = parserStatusCount;
+    m_totalObjectCount = objectCount;
+}
+
+int ExecutableCompilationUnit::totalBindingsCount() const {
+    if (icRoot == -1)
+        return m_totalBindingsCount;
+    return inlineComponentData[icRoot].totalBindingCount;
+}
+
+int ExecutableCompilationUnit::totalObjectCount() const {
+    if (icRoot == -1)
+        return m_totalObjectCount;
+    return inlineComponentData[icRoot].totalObjectCount;
+}
+
+int ExecutableCompilationUnit::totalParserStatusCount() const {
+    if (icRoot == -1)
+        return m_totalParserStatusCount;
+    return inlineComponentData[icRoot].totalParserStatusCount;
 }
 
 bool ExecutableCompilationUnit::verifyChecksum(const CompiledData::DependentTypesHasher &dependencyHasher) const
@@ -453,6 +532,13 @@ bool ExecutableCompilationUnit::verifyChecksum(const CompiledData::DependentType
                       sizeof(data->dependencyMD5Checksum)) == 0;
 }
 
+CompositeMetaTypeIds ExecutableCompilationUnit::typeIdsForComponent(int objectid) const
+{
+    if (objectid == 0)
+        return {metaTypeId, listMetaTypeId};
+    return inlineComponentData[objectid].typeIds;
+}
+
 QStringList ExecutableCompilationUnit::moduleRequests() const
 {
     QStringList requests;
@@ -734,13 +820,14 @@ QQmlRefPointer<QQmlPropertyCache> ResolvedTypeReference::createPropertyCache(QQm
         typePropertyCache = QQmlEnginePrivate::get(engine)->cache(type.metaObject(), minorVersion);
         return typePropertyCache;
     } else {
+        Q_ASSERT(compilationUnit);
         return compilationUnit->rootPropertyCache();
     }
 }
 
 bool ResolvedTypeReference::addToHash(QCryptographicHash *hash, QQmlEngine *engine)
 {
-    if (type.isValid()) {
+    if (type.isValid() && !type.isInlineComponentType()) {
         bool ok = false;
         hash->addData(createPropertyCache(engine)->checksum(&ok));
         return ok;
diff --git a/src/qml/jsruntime/qv4executablecompilationunit_p.h b/src/qml/jsruntime/qv4executablecompilationunit_p.h
index 1272e7a2c3..8cad18a3dc 100644
--- a/src/qml/jsruntime/qv4executablecompilationunit_p.h
+++ b/src/qml/jsruntime/qv4executablecompilationunit_p.h
@@ -64,6 +64,26 @@ QT_BEGIN_NAMESPACE
 
 class QQmlScriptData;
 class QQmlEnginePrivate;
+
+struct InlineComponentData {
+
+    InlineComponentData() = default;
+    InlineComponentData(const CompositeMetaTypeIds &typeIds, int objectIndex, int nameIndex, int totalObjectCount, int totalBindingCount, int totalParserStatusCount)
+        :   typeIds(typeIds)
+          , objectIndex(objectIndex)
+          , nameIndex(nameIndex)
+          , totalObjectCount(totalObjectCount)
+          , totalBindingCount(totalBindingCount)
+          , totalParserStatusCount(totalParserStatusCount) {}
+
+    CompositeMetaTypeIds typeIds;
+    int objectIndex = -1;
+    int nameIndex = -1;
+    int totalObjectCount = 0;
+    int totalBindingCount = 0;
+    int totalParserStatusCount = 0;
+};
+
 namespace QV4 {
 
 // index is per-object binding index
@@ -143,11 +163,16 @@ public:
     QHash<int, IdentifierHash> namedObjectsPerComponentCache;
     inline IdentifierHash namedObjectsPerComponent(int componentObjectIndex);
 
-    void finalizeCompositeType(QQmlEnginePrivate *qmlEngine, QQmlMetaType::CompositeMetaTypeIds typeIds);
+    void finalizeCompositeType(QQmlEnginePrivate *qmlEngine, CompositeMetaTypeIds typeIdsForComponent);
 
-    int totalBindingsCount = 0; // Number of bindings used in this type
-    int totalParserStatusCount = 0; // Number of instantiated types that are QQmlParserStatus subclasses
-    int totalObjectCount = 0; // Number of objects explicitly instantiated
+    int m_totalBindingsCount = 0; // Number of bindings used in this type
+    int m_totalParserStatusCount = 0; // Number of instantiated types that are QQmlParserStatus subclasses
+    int m_totalObjectCount = 0; // Number of objects explicitly instantiated
+    int icRoot = -1;
+
+    int totalBindingsCount() const;
+    int totalParserStatusCount() const;
+    int totalObjectCount() const;
 
     QVector<QQmlRefPointer<QQmlScriptData>> dependentScripts;
     ResolvedTypeReferenceMap resolvedTypes;
@@ -155,12 +180,14 @@ public:
 
     bool verifyChecksum(const CompiledData::DependentTypesHasher &dependencyHasher) const;
 
-    QQmlMetaType::CompositeMetaTypeIds typeIds() const { return {metaTypeId, listMetaTypeId}; }
+    CompositeMetaTypeIds typeIdsForComponent(int objectid = 0) const;
 
     int metaTypeId = -1;
     int listMetaTypeId = -1;
     bool isRegisteredWithEngine = false;
 
+    QHash<int, InlineComponentData> inlineComponentData;
+
     QScopedPointer<CompilationUnitMapper> backingFile;
 
     // --- interface for QQmlPropertyCacheCreator
diff --git a/src/qml/jsruntime/qv4include.cpp b/src/qml/jsruntime/qv4include.cpp
index 92face6f94..64ca719e29 100644
--- a/src/qml/jsruntime/qv4include.cpp
+++ b/src/qml/jsruntime/qv4include.cpp
@@ -163,7 +163,7 @@ void QV4Include::finished()
     QV4::Scope scope(v4);
     QV4::ScopedObject resultObj(scope, m_resultObject.value());
     QV4::ScopedString status(scope, v4->newString(QStringLiteral("status")));
-    if (m_reply->error() == QNetworkReply::NoError) {
+    if (m_reply->networkError() == QNetworkReply::NoError) {
         QByteArray data = m_reply->readAll();
 
         QString code = QString::fromUtf8(data);
diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index 5a81f24e06..9613d064c4 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -1654,7 +1654,7 @@ static QV4::ReturnedValue CallOverloaded(const QQmlObjectOrGadget &object, const
 }
 
 CallArgument::CallArgument()
-: type(QVariant::Invalid)
+: type(QMetaType::UnknownType)
 {
 }
 
diff --git a/src/qml/jsruntime/qv4variantobject.cpp b/src/qml/jsruntime/qv4variantobject.cpp
index e117e509ab..9d7b3c6e9a 100644
--- a/src/qml/jsruntime/qv4variantobject.cpp
+++ b/src/qml/jsruntime/qv4variantobject.cpp
@@ -65,8 +65,8 @@ void Heap::VariantObject::init(const QVariant &value)
 
 bool VariantObject::Data::isScarce() const
 {
-    QVariant::Type t = data().type();
-    return t == QVariant::Pixmap || t == QVariant::Image;
+    int t = data().userType();
+    return t == QMetaType::QPixmap || t == QMetaType::QImage;
 }
 
 bool VariantObject::virtualIsEqualTo(Managed *m, Managed *other)
@@ -139,7 +139,7 @@ ReturnedValue VariantPrototype::method_toString(const FunctionObject *b, const V
         RETURN_UNDEFINED();
     const QVariant variant = o->d()->data();
     QString result = variant.toString();
-    if (result.isEmpty() && !variant.canConvert(QVariant::String)) {
+    if (result.isEmpty() && !variant.canConvert(QMetaType::QString)) {
         QDebug dbg(&result);
         dbg << variant;
         // QDebug appends a space, we're not interested in continuing the stream so we chop it off.
@@ -154,17 +154,17 @@ ReturnedValue VariantPrototype::method_valueOf(const FunctionObject *b, const Va
     const VariantObject *o = thisObject->as<QV4::VariantObject>();
     if (o) {
         QVariant v = o->d()->data();
-        switch (v.type()) {
-        case QVariant::Invalid:
+        switch (v.userType()) {
+        case QMetaType::UnknownType:
             return Encode::undefined();
-        case QVariant::String:
+        case QMetaType::QString:
             return Encode(b->engine()->newString(v.toString()));
-        case QVariant::Int:
+        case QMetaType::Int:
             return Encode(v.toInt());
-        case QVariant::Double:
-        case QVariant::UInt:
+        case QMetaType::Double:
+        case QMetaType::UInt:
             return Encode(v.toDouble());
-        case QVariant::Bool:
+        case QMetaType::Bool:
             return Encode(v.toBool());
         default:
             if (QMetaType::typeFlags(v.userType()) & QMetaType::IsEnumeration)
diff --git a/src/qml/parser/qqmljs.g b/src/qml/parser/qqmljs.g
index 6fbb9df164..397c0b51a5 100644
--- a/src/qml/parser/qqmljs.g
+++ b/src/qml/parser/qqmljs.g
@@ -91,6 +91,7 @@
 %token T_EXPORT "export"
 %token T_FROM "from"
 %token T_REQUIRED "required"
+%token T_COMPONENT "component"
 
 --- template strings
 %token T_NO_SUBSTITUTION_TEMPLATE"(no subst template)"
@@ -123,7 +124,7 @@
 %token T_FOR_LOOKAHEAD_OK "(for lookahead ok)"
 
 --%left T_PLUS T_MINUS
-%nonassoc T_IDENTIFIER T_COLON T_SIGNAL T_PROPERTY T_READONLY T_ON T_SET T_GET T_OF T_STATIC T_FROM T_AS T_REQUIRED
+%nonassoc T_IDENTIFIER T_COLON T_SIGNAL T_PROPERTY T_READONLY T_ON T_SET T_GET T_OF T_STATIC T_FROM T_AS T_REQUIRED T_COMPONENT
 %nonassoc REDUCE_HERE
 %right T_THEN T_ELSE
 %right T_WITHOUTAS T_AS
@@ -1426,6 +1427,19 @@ UiObjectMember: T_ENUM T_IDENTIFIER T_LBRACE EnumMemberList T_RBRACE;
     }
 ./
 
+UiObjectMember: T_COMPONENT T_IDENTIFIER T_COLON UiObjectDefinition;
+/.
+    case $rule_number: {
+        if (!stringRef(2).front().isUpper()) {
+            diagnostic_messages.append(compileError(loc(2),
+                QLatin1String("Type name must be upper case"), QtWarningMsg));
+        }
+        auto inlineComponent = new (pool) AST::UiInlineComponent(stringRef(2), sym(4).UiObjectDefinition);
+        inlineComponent->componentToken = loc(1);
+        sym(1).Node = inlineComponent;
+    } break;
+./
+
 EnumMemberList: T_IDENTIFIER;
 /.
     case $rule_number: {
@@ -1468,29 +1482,31 @@ EnumMemberList: EnumMemberList T_COMMA T_IDENTIFIER T_EQ T_NUMERIC_LITERAL;
     }
 ./
 
-QmlIdentifier: T_IDENTIFIER;
-QmlIdentifier: T_PROPERTY;
-QmlIdentifier: T_SIGNAL;
-QmlIdentifier: T_READONLY;
-QmlIdentifier: T_ON;
-QmlIdentifier: T_GET;
-QmlIdentifier: T_SET;
-QmlIdentifier: T_FROM;
-QmlIdentifier: T_OF;
-QmlIdentifier: T_REQUIRED;
-
-JsIdentifier: T_IDENTIFIER;
-JsIdentifier: T_PROPERTY;
-JsIdentifier: T_SIGNAL;
-JsIdentifier: T_READONLY;
-JsIdentifier: T_ON;
-JsIdentifier: T_GET;
-JsIdentifier: T_SET;
-JsIdentifier: T_FROM;
-JsIdentifier: T_STATIC;
-JsIdentifier: T_OF;
-JsIdentifier: T_AS;
-JsIdentifier: T_REQUIRED;
+QmlIdentifier: T_IDENTIFIER
+             | T_PROPERTY
+             | T_SIGNAL
+             | T_READONLY
+             | T_ON
+             | T_GET
+             | T_SET
+             | T_FROM
+             | T_OF
+             | T_REQUIRED
+             | T_COMPONENT;
+
+JsIdentifier: T_IDENTIFIER
+            | T_PROPERTY
+            | T_SIGNAL
+            | T_READONLY
+            | T_ON
+            | T_GET
+            | T_SET
+            | T_FROM
+            | T_STATIC
+            | T_OF
+            | T_AS
+            | T_REQUIRED
+            | T_COMPONENT;
 
 IdentifierReference: JsIdentifier;
 BindingIdentifier: IdentifierReference;
diff --git a/src/qml/parser/qqmljsast.cpp b/src/qml/parser/qqmljsast.cpp
index 03355b3e38..aa3e8ab5e3 100644
--- a/src/qml/parser/qqmljsast.cpp
+++ b/src/qml/parser/qqmljsast.cpp
@@ -1545,6 +1545,15 @@ void Type::toString(QString *out) const
     };
 }
 
+void UiInlineComponent::accept0(Visitor *visitor)
+{
+    if (visitor->visit(this)) {
+        accept(component, visitor);
+    }
+
+    visitor->endVisit(this);
+}
+
 } } // namespace QQmlJS::AST
 
 QT_END_NAMESPACE
diff --git a/src/qml/parser/qqmljsast_p.h b/src/qml/parser/qqmljsast_p.h
index aa355fed85..48a994cd33 100644
--- a/src/qml/parser/qqmljsast_p.h
+++ b/src/qml/parser/qqmljsast_p.h
@@ -244,6 +244,7 @@ public:
         Kind_UiImport,
         Kind_UiObjectBinding,
         Kind_UiObjectDefinition,
+        Kind_UiInlineComponent,
         Kind_UiObjectInitializer,
         Kind_UiObjectMemberList,
         Kind_UiArrayMemberList,
@@ -3377,6 +3378,28 @@ public:
     UiObjectInitializer *initializer;
 };
 
+class QML_PARSER_EXPORT UiInlineComponent: public UiObjectMember
+{
+public:
+    QQMLJS_DECLARE_AST_NODE(UiInlineComponent)
+
+    UiInlineComponent(const QStringRef& inlineComponentName, UiObjectDefinition* inlineComponent)
+        : name(inlineComponentName), component(inlineComponent)
+    { kind = K; }
+
+    QStringRef name;
+    UiObjectDefinition* component;
+    SourceLocation componentToken;
+
+    SourceLocation lastSourceLocation() const override
+    {return component->lastSourceLocation();}
+
+    SourceLocation firstSourceLocation() const override
+    {return componentToken;}
+
+    void accept0(Visitor *visitor) override;
+};
+
 class QML_PARSER_EXPORT UiSourceElement: public UiObjectMember
 {
 public:
diff --git a/src/qml/parser/qqmljsastfwd_p.h b/src/qml/parser/qqmljsastfwd_p.h
index 05226fd043..8a8ee2dfae 100644
--- a/src/qml/parser/qqmljsastfwd_p.h
+++ b/src/qml/parser/qqmljsastfwd_p.h
@@ -169,6 +169,7 @@ class UiImport;
 class UiPublicMember;
 class UiParameterList;
 class UiObjectDefinition;
+class UiInlineComponent;
 class UiObjectInitializer;
 class UiObjectBinding;
 class UiScriptBinding;
diff --git a/src/qml/parser/qqmljsastvisitor_p.h b/src/qml/parser/qqmljsastvisitor_p.h
index 7146cd00ac..d6b92990ad 100644
--- a/src/qml/parser/qqmljsastvisitor_p.h
+++ b/src/qml/parser/qqmljsastvisitor_p.h
@@ -112,6 +112,7 @@ public:
     virtual bool visit(UiEnumDeclaration *) { return true; }
     virtual bool visit(UiEnumMemberList *) { return true; }
     virtual bool visit(UiVersionSpecifier *) { return true; }
+    virtual bool visit(UiInlineComponent *) { return true; }
 
     virtual void endVisit(UiProgram *) {}
     virtual void endVisit(UiImport *) {}
@@ -131,6 +132,7 @@ public:
     virtual void endVisit(UiEnumDeclaration *) {}
     virtual void endVisit(UiEnumMemberList *) { }
     virtual void endVisit(UiVersionSpecifier *) {}
+    virtual void endVisit(UiInlineComponent *) {}
 
     // QQmlJS
     virtual bool visit(ThisExpression *) { return true; }
diff --git a/src/qml/parser/qqmljskeywords_p.h b/src/qml/parser/qqmljskeywords_p.h
index 3eb054341f..5f08cc4353 100644
--- a/src/qml/parser/qqmljskeywords_p.h
+++ b/src/qml/parser/qqmljskeywords_p.h
@@ -836,6 +836,25 @@ static inline int classify9(const QChar *s, int parseModeFlags) {
       }
     }
   }
+  else if (s[0].unicode() == 'c') {
+    if (s[1].unicode() == 'o') {
+      if (s[2].unicode() == 'm') {
+        if (s[3].unicode() == 'p') {
+          if (s[4].unicode() == 'o') {
+            if (s[5].unicode() == 'n') {
+              if (s[6].unicode() == 'e') {
+                if (s[7].unicode() == 'n') {
+                  if (s[8].unicode() == 't') {
+                    return (parseModeFlags & Lexer::QmlMode) ? int(Lexer::T_COMPONENT) : int(Lexer::T_IDENTIFIER);
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
   return Lexer::T_IDENTIFIER;
 }
 
diff --git a/src/qml/qml.pro b/src/qml/qml.pro
index 985f7ca383..5b2ac4b5cf 100644
--- a/src/qml/qml.pro
+++ b/src/qml/qml.pro
@@ -39,6 +39,7 @@ greaterThan(QT_CLANG_MAJOR_VERSION, 3)|greaterThan(QT_CLANG_MINOR_VERSION, 3)| \
     WERROR += -Wno-error=unused-const-variable
 
 HEADERS += qtqmlglobal.h \
+           inlinecomponentutils_p.h \
            qtqmlglobal_p.h \
            qtqmlcompilerglobal.h \
            qtqmlcompilerglobal_p.h
diff --git a/src/qml/qml/ftw/qhashedstring.cpp b/src/qml/qml/ftw/qhashedstring.cpp
index bbe374044d..4553fa9359 100644
--- a/src/qml/qml/ftw/qhashedstring.cpp
+++ b/src/qml/qml/ftw/qhashedstring.cpp
@@ -102,6 +102,25 @@ QHashedStringRef QHashedStringRef::mid(int offset, int length) const
                             (length == -1 || (offset + length) > m_length)?(m_length - offset):length);
 }
 
+QVector<QHashedStringRef> QHashedStringRef::split(const QChar sep) const
+{
+    QVector<QHashedStringRef> ret;
+    auto curLength = 0;
+    auto curOffset = m_data;
+    for (int offset = 0; offset < m_length; ++offset) {
+        if (*(m_data + offset) == sep) {
+            ret.push_back({curOffset, curLength});
+            curOffset = m_data + offset + 1;
+            curLength = 0;
+        } else {
+            ++curLength;
+        }
+    }
+    if (curLength > 0)
+        ret.push_back({curOffset, curLength});
+    return ret;
+}
+
 bool QHashedStringRef::endsWith(const QString &s) const
 {
     return s.length() < m_length &&
diff --git a/src/qml/qml/ftw/qhashedstring_p.h b/src/qml/qml/ftw/qhashedstring_p.h
index b9f3f81219..a2e10ff143 100644
--- a/src/qml/qml/ftw/qhashedstring_p.h
+++ b/src/qml/qml/ftw/qhashedstring_p.h
@@ -125,6 +125,7 @@ public:
     bool endsWith(const QString &) const;
     int indexOf(const QChar &, int from=0) const;
     QHashedStringRef mid(int, int) const;
+    QVector<QHashedStringRef> split(const QChar sep) const;
 
     inline bool isEmpty() const;
     inline int length() const;
diff --git a/src/qml/qml/qqmlapplicationengine.cpp b/src/qml/qml/qqmlapplicationengine.cpp
index 7f80fe5e1c..7d961cd0c7 100644
--- a/src/qml/qml/qqmlapplicationengine.cpp
+++ b/src/qml/qml/qqmlapplicationengine.cpp
@@ -50,6 +50,7 @@ QT_BEGIN_NAMESPACE
 QQmlApplicationEnginePrivate::QQmlApplicationEnginePrivate(QQmlEngine *e)
     : QQmlEnginePrivate(e)
 {
+    uiLanguage = QLocale().bcp47Name();
 }
 
 QQmlApplicationEnginePrivate::~QQmlApplicationEnginePrivate()
@@ -72,6 +73,7 @@ void QQmlApplicationEnginePrivate::init()
                &QCoreApplication::quit, Qt::QueuedConnection);
     q->connect(q, &QQmlApplicationEngine::exit, QCoreApplication::instance(),
                &QCoreApplication::exit, Qt::QueuedConnection);
+    q->connect(q, SIGNAL(uiLanguageChanged()), q_func(), SLOT(_q_loadTranslations()));
 #if QT_CONFIG(translation)
     QTranslator* qtTranslator = new QTranslator(q);
     if (qtTranslator->load(QLocale(), QLatin1String("qt"), QLatin1String("_"), QLibraryInfo::location(QLibraryInfo::TranslationsPath), QLatin1String(".qm")))
@@ -83,20 +85,27 @@ void QQmlApplicationEnginePrivate::init()
     QCoreApplication::instance()->setProperty("__qml_using_qqmlapplicationengine", QVariant(true));
 }
 
-void QQmlApplicationEnginePrivate::loadTranslations(const QUrl &rootFile)
+void QQmlApplicationEnginePrivate::_q_loadTranslations()
 {
 #if QT_CONFIG(translation)
-    if (rootFile.scheme() != QLatin1String("file") && rootFile.scheme() != QLatin1String("qrc"))
+    if (translationsDirectory.isEmpty())
         return;
 
-    QFileInfo fi(QQmlFile::urlToLocalFileOrQrc(rootFile));
-
     Q_Q(QQmlApplicationEngine);
-    QTranslator *translator = new QTranslator(q);
-    if (translator->load(QLocale(), QLatin1String("qml"), QLatin1String("_"), fi.path() + QLatin1String("/i18n"), QLatin1String(".qm")))
-        QCoreApplication::installTranslator(translator);
-    else
-        delete translator;
+
+    QScopedPointer<QTranslator> translator(new QTranslator);
+    if (!uiLanguage.isEmpty()) {
+        QLocale locale(uiLanguage);
+        if (translator->load(locale, QLatin1String("qml"), QLatin1String("_"), translationsDirectory, QLatin1String(".qm"))) {
+            if (activeTranslator)
+                QCoreApplication::removeTranslator(activeTranslator.data());
+            QCoreApplication::installTranslator(translator.data());
+            activeTranslator.swap(translator);
+        }
+    } else {
+        activeTranslator.reset();
+    }
+    q->retranslate();
 #else
     Q_UNUSED(rootFile)
 #endif
@@ -106,7 +115,14 @@ void QQmlApplicationEnginePrivate::startLoad(const QUrl &url, const QByteArray &
 {
     Q_Q(QQmlApplicationEngine);
 
-    loadTranslations(url); //Translations must be loaded before the QML file is
+    if (url.scheme() == QLatin1String("file") || url.scheme() == QLatin1String("qrc")) {
+        QFileInfo fi(QQmlFile::urlToLocalFileOrQrc(url));
+        translationsDirectory = fi.path() + QLatin1String("/i18n");
+    } else {
+        translationsDirectory.clear();
+    }
+
+    _q_loadTranslations(); //Translations must be loaded before the QML file is
     QQmlComponent *c = new QQmlComponent(q, q);
 
     if (dataFlag)
@@ -181,6 +197,7 @@ void QQmlApplicationEnginePrivate::finishLoad(QQmlComponent *c)
       \list
           \li Translation files must have "qml_" prefix e.g. qml_ja_JP.qm.
       \endlist
+  \li Translations are reloaded when the \c QJSEngine::uiLanguage / \c Qt.uiLanguage property is changed.
   \li Automatically sets an incubation controller if the scene contains a QQuickWindow.
   \li Automatically sets a \c QQmlFileSelector as the url interceptor, applying file selectors to all
   QML files and assets.
diff --git a/src/qml/qml/qqmlapplicationengine.h b/src/qml/qml/qqmlapplicationengine.h
index 2b4de91154..37f75d5068 100644
--- a/src/qml/qml/qqmlapplicationengine.h
+++ b/src/qml/qml/qqmlapplicationengine.h
@@ -74,6 +74,7 @@ Q_SIGNALS:
 
 private:
     Q_DISABLE_COPY(QQmlApplicationEngine)
+    Q_PRIVATE_SLOT(d_func(), void _q_loadTranslations())
     Q_DECLARE_PRIVATE(QQmlApplicationEngine)
 };
 
diff --git a/src/qml/qml/qqmlapplicationengine_p.h b/src/qml/qml/qqmlapplicationengine_p.h
index 1279e400e8..c514e3daf9 100644
--- a/src/qml/qml/qqmlapplicationengine_p.h
+++ b/src/qml/qml/qqmlapplicationengine_p.h
@@ -70,10 +70,12 @@ public:
     void cleanUp();
 
     void startLoad(const QUrl &url, const QByteArray &data = QByteArray(), bool dataFlag = false);
-    void loadTranslations(const QUrl &rootFile);
+    void _q_loadTranslations();
     void finishLoad(QQmlComponent *component);
     QList<QObject *> objects;
     QVariantMap initialProperties;
+    QString translationsDirectory;
+    QScopedPointer<QTranslator> activeTranslator;
 };
 
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index 162adf8364..e14b00af22 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -479,7 +479,7 @@ Q_NEVER_INLINE bool QQmlBinding::slowWrite(const QQmlPropertyData &core,
                 if (!propertyMetaObject.isNull())
                     propertyType = propertyMetaObject.className();
             }
-        } else if (userType != QVariant::Invalid) {
+        } else if (userType != QMetaType::UnknownType) {
             if (userType == QMetaType::Nullptr || userType == QMetaType::VoidStar)
                 valueType = "null";
             else
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index f11959b7fb..5d7dddd153 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -101,8 +101,6 @@
 #  endif
 #endif // Q_OS_WIN
 
-Q_DECLARE_METATYPE(QQmlProperty)
-
 QT_BEGIN_NAMESPACE
 
 // Declared in qqml.h
@@ -1309,6 +1307,21 @@ void QQmlEngine::setOutputWarningsToStandardError(bool enabled)
 }
 
 /*!
+  \qmlproperty string Qt::uiLanguage
+  \since 5.15
+
+  The uiLanguage holds the name of the language to be used for user interface
+  string translations. It is exposed in C++ as QQmlEngine::uiLanguage property.
+
+  You can set the value freely and use it in bindings. It is recommended to set it
+  after installing translators in your application. By convention, an empty string
+  means no translation from the language used in the source code is intended to occur.
+
+  If you're using QQmlApplicationEngine and the value changes, QQmlEngine::retranslate()
+  will be called.
+*/
+
+/*!
   \fn template<typename T> T QQmlEngine::singletonInstance(int qmlTypeId)
 
   Returns the instance of a singleton type that was registered under \a qmlTypeId.
@@ -2341,12 +2354,23 @@ int QQmlEnginePrivate::listType(int t) const
     return QQmlMetaType::listType(t);
 }
 
+
+static QQmlPropertyCache *propertyCacheForPotentialInlineComponentType(int t, const QHash<int, QV4::ExecutableCompilationUnit *>::const_iterator &iter) {
+    if (t != (*iter)->metaTypeId) {
+        // this is an inline component, and what we have in the iterator is currently the parent compilation unit
+        for (auto &&icDatum: (*iter)->inlineComponentData)
+            if (icDatum.typeIds.id == t)
+                return (*iter)->propertyCaches.at(icDatum.objectIndex);
+    }
+    return (*iter)->rootPropertyCache().data();
+}
+
 QQmlMetaObject QQmlEnginePrivate::rawMetaObjectForType(int t) const
 {
     Locker locker(this);
     auto iter = m_compositeTypes.constFind(t);
     if (iter != m_compositeTypes.cend()) {
-        return QQmlMetaObject((*iter)->rootPropertyCache().data());
+        return propertyCacheForPotentialInlineComponentType(t, iter);
     } else {
         QQmlType type = QQmlMetaType::qmlType(t);
         return QQmlMetaObject(type.baseMetaObject());
@@ -2358,7 +2382,7 @@ QQmlMetaObject QQmlEnginePrivate::metaObjectForType(int t) const
     Locker locker(this);
     auto iter = m_compositeTypes.constFind(t);
     if (iter != m_compositeTypes.cend()) {
-        return QQmlMetaObject((*iter)->rootPropertyCache().data());
+        return propertyCacheForPotentialInlineComponentType(t, iter);
     } else {
         QQmlType type = QQmlMetaType::qmlType(t);
         return QQmlMetaObject(type.metaObject());
@@ -2370,7 +2394,7 @@ QQmlPropertyCache *QQmlEnginePrivate::propertyCacheForType(int t)
     Locker locker(this);
     auto iter = m_compositeTypes.constFind(t);
     if (iter != m_compositeTypes.cend()) {
-        return (*iter)->rootPropertyCache().data();
+        return propertyCacheForPotentialInlineComponentType(t, iter);
     } else {
         QQmlType type = QQmlMetaType::qmlType(t);
         locker.unlock();
@@ -2383,7 +2407,7 @@ QQmlPropertyCache *QQmlEnginePrivate::rawPropertyCacheForType(int t, int minorVe
     Locker locker(this);
     auto iter = m_compositeTypes.constFind(t);
     if (iter != m_compositeTypes.cend()) {
-        return (*iter)->rootPropertyCache().data();
+        return propertyCacheForPotentialInlineComponentType(t, iter);
     } else {
         QQmlType type = QQmlMetaType::qmlType(t);
         locker.unlock();
@@ -2403,6 +2427,9 @@ void QQmlEnginePrivate::registerInternalCompositeType(QV4::ExecutableCompilation
     // The QQmlCompiledData is not referenced here, but it is removed from this
     // hash in the QQmlCompiledData destructor
     m_compositeTypes.insert(compilationUnit->metaTypeId, compilationUnit);
+    for (auto &&data: compilationUnit->inlineComponentData) {
+        m_compositeTypes.insert(data.typeIds.id, compilationUnit);
+    }
 }
 
 void QQmlEnginePrivate::unregisterInternalCompositeType(QV4::ExecutableCompilationUnit *compilationUnit)
@@ -2411,6 +2438,14 @@ void QQmlEnginePrivate::unregisterInternalCompositeType(QV4::ExecutableCompilati
 
     Locker locker(this);
     m_compositeTypes.remove(compilationUnit->metaTypeId);
+    for (auto&& icDatum: compilationUnit->inlineComponentData)
+        m_compositeTypes.remove(icDatum.typeIds.id);
+}
+
+QV4::ExecutableCompilationUnit *QQmlEnginePrivate::obtainExecutableCompilationUnit(int typeId)
+{
+    Locker locker(this);
+    return m_compositeTypes.value(typeId, nullptr);
 }
 
 template<>
diff --git a/src/qml/qml/qqmlengine_p.h b/src/qml/qml/qqmlengine_p.h
index 98c7823921..33fa800ff4 100644
--- a/src/qml/qml/qqmlengine_p.h
+++ b/src/qml/qml/qqmlengine_p.h
@@ -231,6 +231,7 @@ public:
     QQmlPropertyCache *rawPropertyCacheForType(int, int minorVersion = -1);
     void registerInternalCompositeType(QV4::ExecutableCompilationUnit *compilationUnit);
     void unregisterInternalCompositeType(QV4::ExecutableCompilationUnit *compilationUnit);
+    QV4::ExecutableCompilationUnit *obtainExecutableCompilationUnit(int typeId);
 
     bool isTypeLoaded(const QUrl &url) const;
     bool isScriptLoaded(const QUrl &url) const;
diff --git a/src/qml/qml/qqmlfile.cpp b/src/qml/qml/qqmlfile.cpp
index 465a342129..ee54359d0f 100644
--- a/src/qml/qml/qqmlfile.cpp
+++ b/src/qml/qml/qqmlfile.cpp
@@ -187,7 +187,7 @@ void QQmlFileNetworkReply::networkFinished()
         }
     }
 
-    if (m_reply->error()) {
+    if (m_reply->networkError()) {
         m_p->errorString = m_reply->errorString();
         m_p->error = QQmlFilePrivate::Network;
     } else {
diff --git a/src/qml/qml/qqmlimport.cpp b/src/qml/qml/qqmlimport.cpp
index 7da0685872..80eafdf146 100644
--- a/src/qml/qml/qqmlimport.cpp
+++ b/src/qml/qml/qqmlimport.cpp
@@ -58,6 +58,7 @@
 #include <private/qqmltypeloaderqmldircontent_p.h>
 #include <QtCore/qjsonobject.h>
 #include <QtCore/qjsonarray.h>
+#include <QtQml/private/qqmltype_p_p.h>
 
 #include <algorithm>
 #include <functional>
@@ -613,6 +614,8 @@ bool QQmlImports::resolveType(const QHashedStringRef &type,
                         RESOLVE_TYPE_DEBUG << type_return->typeName() << ' ' << type_return->sourceUrl() << " TYPE/URL-SINGLETON";
                     else if (type_return->isComposite())
                         RESOLVE_TYPE_DEBUG << type_return->typeName() << ' ' << type_return->sourceUrl() << " TYPE/URL";
+                    else if (type_return->isInlineComponentType())
+                        RESOLVE_TYPE_DEBUG << type_return->typeName() << ' ' << type_return->sourceUrl() << " TYPE(INLINECOMPONENT)";
                     else
                         RESOLVE_TYPE_DEBUG << type_return->typeName() << " TYPE";
                 }
@@ -709,6 +712,37 @@ bool QQmlImportInstance::resolveType(QQmlTypeLoader *typeLoader, const QHashedSt
     }
 
     const QString typeStr = type.toString();
+    if (isInlineComponent) {
+        Q_ASSERT(type_return);
+        bool ret = uri == typeStr;
+        if (ret) {
+            Q_ASSERT(!type_return->isValid());
+            auto createICType = [&]() {
+                auto typePriv = new QQmlTypePrivate {QQmlType::RegistrationType::InlineComponentType};
+                bool ok = false;
+                typePriv->extraData.id->objectId = QUrl(this->url).fragment().toInt(&ok);
+                Q_ASSERT(ok);
+                typePriv->extraData.id->url = QUrl(this->url);
+                auto icType = QQmlType(typePriv);
+                return icType;
+            };
+            if (containingType.isValid()) {
+                // we currently cannot reference a Singleton inside itself
+                // in that case, containingType is still invalid
+                if (int icID = containingType.lookupInlineComponentIdByName(typeStr) != -1) {
+                    *type_return = containingType.lookupInlineComponentById(icID);
+                } else {
+                    auto icType = createICType();
+                    int placeholderId = containingType.generatePlaceHolderICId();
+                    const_cast<QQmlImportInstance*>(this)->containingType.associateInlineComponent(typeStr, placeholderId, CompositeMetaTypeIds {}, icType);
+                    *type_return = QQmlType(icType);
+                }
+            } else  {
+                *type_return = createICType();
+            }
+        }
+        return ret;
+    }
     QQmlDirComponents::ConstIterator it = qmlDirComponents.find(typeStr), end = qmlDirComponents.end();
     if (it != end) {
         QString componentUrl;
@@ -826,47 +860,107 @@ bool QQmlImportsPrivate::resolveType(const QHashedStringRef& type, int *vmajor,
                                      QQmlType::RegistrationType registrationType,
                                      bool *typeRecursionDetected)
 {
-    QQmlImportNamespace *s = nullptr;
-    int dot = type.indexOf(Dot);
-    if (dot >= 0) {
-        QHashedStringRef namespaceName(type.constData(), dot);
-        s = findQualifiedNamespace(namespaceName);
-        if (!s) {
-            if (errors) {
-                QQmlError error;
-                error.setDescription(QQmlImportDatabase::tr("- %1 is not a namespace").arg(namespaceName.toString()));
-                errors->prepend(error);
-            }
-            return false;
-        }
-        int ndot = type.indexOf(Dot,dot+1);
-        if (ndot > 0) {
-            if (errors) {
-                QQmlError error;
-                error.setDescription(QQmlImportDatabase::tr("- nested namespaces not allowed"));
-                errors->prepend(error);
-            }
-            return false;
-        }
-    } else {
-        s = &unqualifiedset;
-    }
-    QHashedStringRef unqualifiedtype = dot < 0 ? type : QHashedStringRef(type.constData()+dot+1, type.length()-dot-1);
-    if (s) {
-        if (s->resolveType(typeLoader, unqualifiedtype, vmajor, vminor, type_return, &base, errors,
+    const QVector<QHashedStringRef> splitName = type.split(Dot);
+    auto resolveTypeInNamespace = [&](QHashedStringRef unqualifiedtype, QQmlImportNamespace *nameSpace, QList<QQmlError> *errors) -> bool {
+        if (nameSpace->resolveType(typeLoader, unqualifiedtype, vmajor, vminor, type_return, &base, errors,
                            registrationType, typeRecursionDetected))
             return true;
-        if (s->imports.count() == 1 && !s->imports.at(0)->isLibrary && type_return && s != &unqualifiedset) {
+        if (nameSpace->imports.count() == 1 && !nameSpace->imports.at(0)->isLibrary && type_return && nameSpace != &unqualifiedset) {
             // qualified, and only 1 url
             *type_return = QQmlMetaType::typeForUrl(
-                    resolveLocalUrl(s->imports.at(0)->url,
+                    resolveLocalUrl(nameSpace->imports.at(0)->url,
                                     unqualifiedtype.toString() + QLatin1String(".qml")),
                     type, false, errors);
             return type_return->isValid();
         }
+        return false;
+    };
+    switch (splitName.size()) {
+    case 1: {
+        // must be a simple type
+        return resolveTypeInNamespace(type, &unqualifiedset, errors);
     }
-
-    return false;
+    case 2: {
+        // either namespace + simple type OR simple type + inline component
+        QQmlImportNamespace *s = findQualifiedNamespace(splitName.at(0));
+        if (s) {
+            // namespace + simple type
+            return resolveTypeInNamespace(splitName.at(1), s, errors);
+        } else {
+            if (resolveTypeInNamespace(splitName.at(0), &unqualifiedset, nullptr)) {
+                // either simple type + inline component
+                auto const icName = splitName.at(1).toString();
+                auto objectIndex = type_return->lookupInlineComponentIdByName(icName);
+                if (objectIndex != -1) {
+                    *type_return = type_return->lookupInlineComponentById(objectIndex);
+                } else {
+                    auto icTypePriv = new QQmlTypePrivate(QQmlType::RegistrationType::InlineComponentType);
+                    icTypePriv->setContainingType(type_return);
+                    icTypePriv->extraData.id->url = type_return->sourceUrl();
+                    int placeholderId = type_return->generatePlaceHolderICId();
+                    icTypePriv->extraData.id->url.setFragment(QString::number(placeholderId));
+                    auto icType = QQmlType(icTypePriv);
+                    type_return->associateInlineComponent(icName, placeholderId, CompositeMetaTypeIds {}, icType);
+                    *type_return = icType;
+                }
+                Q_ASSERT(type_return->containingType().isValid());
+                type_return->setPendingResolutionName(icName);
+                return true;
+            } else {
+                // or a failure
+                if (errors) {
+                    QQmlError error;
+                    error.setDescription(QQmlImportDatabase::tr("- %1 is neither a type nor a namespace").arg(splitName.at(0).toString()));
+                    errors->prepend(error);
+                }
+                return false;
+            }
+        }
+    }
+    case 3: {
+        // must be namespace + simple type + inline component
+        QQmlImportNamespace *s = findQualifiedNamespace(splitName.at(0));
+        QQmlError error;
+        if (!s) {
+            error.setDescription(QQmlImportDatabase::tr("- %1 is not a namespace").arg(splitName.at(0).toString()));
+        } else {
+            if (resolveTypeInNamespace(splitName.at(1), s, nullptr)) {
+                auto const icName = splitName.at(2).toString();
+                auto objectIndex = type_return->lookupInlineComponentIdByName(icName);
+                if (objectIndex != -1)
+                    *type_return = type_return->lookupInlineComponentById(objectIndex);
+                else {
+                    auto icTypePriv = new QQmlTypePrivate(QQmlType::RegistrationType::InlineComponentType);
+                    icTypePriv->setContainingType(type_return);
+                    icTypePriv->extraData.id->url = type_return->sourceUrl();
+                    int placeholderId = type_return->generatePlaceHolderICId();
+                    icTypePriv->extraData.id->url.setFragment(QString::number(placeholderId));
+                    auto icType = QQmlType(icTypePriv);
+                    type_return->associateInlineComponent(icName, placeholderId, CompositeMetaTypeIds {}, icType);
+                    *type_return = icType;
+                }
+                type_return->setPendingResolutionName(icName);
+                return true;
+            } else {
+                error.setDescription(QQmlImportDatabase::tr("- %1 is not a type").arg(splitName.at(1).toString()));
+            }
+        }
+        if (errors) {
+            errors->prepend(error);
+        }
+        return false;
+    }
+    default: {
+        // all other numbers suggest a user error
+        if (errors) {
+            QQmlError error;
+            error.setDescription(QQmlImportDatabase::tr("- nested namespaces not allowed"));
+            errors->prepend(error);
+        }
+        return false;
+    }
+    }
+    Q_UNREACHABLE();
 }
 
 QQmlImportInstance *QQmlImportNamespace::findImport(const QString &uri) const
@@ -1652,6 +1746,21 @@ bool QQmlImports::addImplicitImport(QQmlImportDatabase *importDb, QList<QQmlErro
 }
 
 /*!
+ \internal
+ */
+bool QQmlImports::addInlineComponentImport(QQmlImportInstance *const importInstance, const QString &name, const QUrl importUrl, QQmlType containingType)
+{
+    importInstance->url = importUrl.toString();
+    importInstance->uri = name;
+    importInstance->isInlineComponent = true;
+    importInstance->majversion = 0;
+    importInstance->minversion = 0;
+    importInstance->containingType = containingType;
+    d->unqualifiedset.imports.push_back(importInstance);
+    return true;
+}
+
+/*!
   \internal
 
   Adds information to \a imports such that subsequent calls to resolveType()
diff --git a/src/qml/qml/qqmlimport_p.h b/src/qml/qml/qqmlimport_p.h
index 1f44b22deb..2e994fd27f 100644
--- a/src/qml/qml/qqmlimport_p.h
+++ b/src/qml/qml/qqmlimport_p.h
@@ -80,10 +80,12 @@ struct QQmlImportInstance
     QString uri; // e.g. QtQuick
     QString url; // the base path of the import
     QString localDirectoryPath; // the base path of the import if it's a local file
+    QQmlType containingType; // points to the containing type for inline components
     int majversion; // the major version imported
     int minversion; // the minor version imported
     bool isLibrary; // true means that this is not a file import
     bool implicitlyImported = false;
+    bool isInlineComponent = false;
     QQmlDirComponents qmlDirComponents; // a copy of the components listed in the qmldir
     QQmlDirScripts qmlDirScripts; // a copy of the scripts in the qmldir
 
@@ -151,6 +153,8 @@ public:
 
     bool addImplicitImport(QQmlImportDatabase *importDb, QList<QQmlError> *errors);
 
+    bool addInlineComponentImport(QQmlImportInstance  *const importInstance, const QString &name, const QUrl importUrl, QQmlType containingType);
+
     bool addFileImport(QQmlImportDatabase *,
                        const QString& uri, const QString& prefix, int vmaj, int vmin, bool incomplete,
                        QList<QQmlError> *errors);
diff --git a/src/qml/qml/qqmlirloader.cpp b/src/qml/qml/qqmlirloader.cpp
index 82cad8eba8..b284e44fdf 100644
--- a/src/qml/qml/qqmlirloader.cpp
+++ b/src/qml/qml/qqmlirloader.cpp
@@ -200,6 +200,13 @@ QmlIR::Object *QQmlIRLoader::loadObject(const QV4::CompiledData::Object *seriali
 
     object->runtimeFunctionIndices.allocate(pool, functionIndices);
 
+    const QV4::CompiledData::InlineComponent *serializedInlineComponent = serializedObject->inlineComponentTable();
+    for (uint i = 0; i < serializedObject->nInlineComponents; ++i, ++serializedInlineComponent) {
+        QmlIR::InlineComponent *ic = pool->New<QmlIR::InlineComponent>();
+        *static_cast<QV4::CompiledData::InlineComponent*>(ic) = *serializedInlineComponent;
+        object->inlineComponents->append(ic);
+    }
+
     return object;
 }
 
diff --git a/src/qml/qml/qqmllist.cpp b/src/qml/qml/qqmllist.cpp
index 5425bf498c..b504fdf22d 100644
--- a/src/qml/qml/qqmllist.cpp
+++ b/src/qml/qml/qqmllist.cpp
@@ -250,10 +250,37 @@ bool QQmlListReference::canCount() const
 }
 
 /*!
-    Return true if at(), count(), append() and clear() are implemented, so you can manipulate
-    the list.
+Returns true if items in the list property can be replaced, otherwise false.
+Returns false if the reference is invalid.
+
+\sa replace()
+*/
+bool QQmlListReference::canReplace() const
+{
+    return (isValid() && d->property.replace);
+}
+
+/*!
+Returns true if the last item can be removed from the list property, otherwise false.
+Returns false if the reference is invalid.
+
+\sa removeLast()
+*/
+bool QQmlListReference::canRemoveLast() const
+{
+    return (isValid() && d->property.removeLast);
+}
+
+/*!
+    Return true if at(), count(), append(), and either clear() or removeLast()
+    are implemented, so you can manipulate the list.
+
+    Mind that replace() and removeLast() can be emulated by stashing all
+    items and rebuilding the list using clear() and append(). Therefore,
+    they are not required for the list to be manipulable. Furthermore,
+    clear() can be emulated using removeLast().
 
-\sa isReadable(), at(), count(), append(), clear()
+\sa isReadable(), at(), count(), append(), clear(), replace(), removeLast()
 */
 bool QQmlListReference::isManipulable() const
 {
@@ -329,6 +356,39 @@ int QQmlListReference::count() const
 }
 
 /*!
+Replaces the item at \a index in the list with \a object.
+Returns true if the operation succeeded, otherwise false.
+
+\sa canReplace()
+*/
+bool QQmlListReference::replace(int index, QObject *object) const
+{
+    if (!canReplace())
+        return false;
+
+    if (object && !QQmlMetaObject::canConvert(object, d->elementType))
+        return false;
+
+    d->property.replace(&d->property, index, object);
+    return true;
+}
+
+/*!
+Removes the last item in the list.
+Returns true if the operation succeeded, otherwise false.
+
+\sa canRemoveLast()
+*/
+bool QQmlListReference::removeLast() const
+{
+    if (!canRemoveLast())
+        return false;
+
+    d->property.removeLast(&d->property);
+    return true;
+}
+
+/*!
 \class QQmlListProperty
 \since 5.0
 \inmodule QtQml
@@ -375,14 +435,25 @@ QML list properties are type-safe - in this case \c {Fruit} is a QObject type th
 
 /*!
 \fn template<typename T> QQmlListProperty<T>::QQmlListProperty(QObject *object, QList<T *> &list)
+\deprecated
 
 Convenience constructor for making a QQmlListProperty value from an existing
 QList \a list.  The \a list reference must remain valid for as long as \a object
 exists.  \a object must be provided.
 
-Generally this constructor should not be used in production code, as a
-writable QList violates QML's memory management rules.  However, this constructor
-can be very useful while prototyping.
+This constructor synthesizes the removeLast() and replace() methods
+introduced in Qt 5.15, using count(), at(), clear(), and append(). This is slow.
+If you intend to manipulate the list beyond clearing it, you should explicitly
+provide these methods.
+*/
+
+/*!
+\fn template<typename T> QQmlListProperty<T>::QQmlListProperty(QObject *object, QList<T *> *list)
+\since 5.15
+
+Convenience constructor for making a QQmlListProperty value from an existing
+QList \a list. The \a list reference must remain valid for as long as \a object
+exists. \a object must be provided.
 */
 
 /*!
@@ -408,6 +479,39 @@ remains valid while \a object exists.
 Null pointers can be passed for any function. If any null pointers are passed in, the list
 will be neither designable nor alterable by the debugger. It is recommended to provide valid
 pointers for all functions.
+
+\note The resulting QQmlListProperty will synthesize the removeLast() and
+replace() methods using \a count, \a at, \a clear, and \a append if all of those
+are given. This is slow. If you intend to manipulate the list beyond clearing it,
+you should explicitly provide these methods.
+*/
+
+/*!
+\fn template<typename T> QQmlListProperty<T>::QQmlListProperty(
+        QObject *object, void *data, AppendFunction append, CountFunction count,
+        AtFunction at, ClearFunction clear, ReplaceFunction replace,
+        RemoveLastFunction removeLast)
+
+Construct a QQmlListProperty from a set of operation functions \a append,
+\a count, \a at, \a clear, \a replace, and \removeLast. An opaque \a data handle
+may be passed which can be accessed from within the operation functions. The
+list property remains valid while \a object exists.
+
+Null pointers can be passed for any function, causing the respective function to
+be synthesized using the others, if possible. QQmlListProperty can synthesize
+\list
+    \li \a clear using \a count and \a removeLast
+    \li \a replace using \a count, \a at, \a clear, and \a append
+    \li \a replace using \a count, \a at, \a removeLast, and \a append
+    \li \a removeLast using \a count, \a at, \a clear, and \a append
+\endlist
+if those are given. This is slow, but if your list does not natively provide
+faster options for these primitives, you may want to use the synthesized ones.
+
+Furthermore, if either of \a count, \a at, \a append, and \a clear are neither
+given explicitly nor synthesized, the list will be neither designable nor
+alterable by the debugger. It is recommended to provide enough valid pointers
+to avoid this situation.
 */
 
 /*!
@@ -448,4 +552,20 @@ Synonym for \c {void (*)(QQmlListProperty<T> *property)}.
 Clear the list \a property.
 */
 
+/*!
+\typedef QQmlListProperty::ReplaceFunction
+
+Synonym for \c {void (*)(QQmlListProperty<T> *property, int index, T *value)}.
+
+Replace the element at position \a index in the list \a property with \a value.
+*/
+
+/*!
+\typedef QQmlListProperty::RemoveLastFunction
+
+Synonym for \c {void (*)(QQmlListProperty<T> *property)}.
+
+Remove the last element from the list \a property.
+*/
+
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmllist.h b/src/qml/qml/qqmllist.h
index 90ec57c911..17333ca9e4 100644
--- a/src/qml/qml/qqmllist.h
+++ b/src/qml/qml/qqmllist.h
@@ -55,22 +55,28 @@ struct QMetaObject;
 template<typename T>
 class QQmlListProperty {
 public:
-    typedef void (*AppendFunction)(QQmlListProperty<T> *, T*);
-    typedef int (*CountFunction)(QQmlListProperty<T> *);
-    typedef T *(*AtFunction)(QQmlListProperty<T> *, int);
-    typedef void (*ClearFunction)(QQmlListProperty<T> *);
-
-    QQmlListProperty()
-        : append(nullptr),
-          count(nullptr),
-          at(nullptr),
-          clear(nullptr)
-    {}
+    using AppendFunction = void (*)(QQmlListProperty<T> *, T *);
+    using CountFunction = int (*)(QQmlListProperty<T> *);
+    using AtFunction = T *(*)(QQmlListProperty<T> *, int);
+    using ClearFunction = void (*)(QQmlListProperty<T> *);
+    using ReplaceFunction = void (*)(QQmlListProperty<T> *, int, T *);
+    using RemoveLastFunction = void (*)(QQmlListProperty<T> *);
+
+    QQmlListProperty() = default;
+
+#if QT_DEPRECATED_SINCE(5,15)
+    QT_DEPRECATED_X("Use constructor taking QList pointer, and gain improved performance")
     QQmlListProperty(QObject *o, QList<T *> &list)
         : object(o), data(&list), append(qlist_append), count(qlist_count), at(qlist_at),
-          clear(qlist_clear)
+          clear(qlist_clear), replace(qslow_replace), removeLast(qslow_removeLast)
+    {}
+#endif
 
+    QQmlListProperty(QObject *o, QList<T *> *list)
+        : object(o), data(list), append(qlist_append), count(qlist_count), at(qlist_at),
+          clear(qlist_clear), replace(qlist_replace), removeLast(qlist_removeLast)
     {}
+
     QQmlListProperty(QObject *o, void *d, AppendFunction a, CountFunction c, AtFunction t,
                     ClearFunction r )
         : object(o),
@@ -78,37 +84,47 @@ public:
           append(a),
           count(c),
           at(t),
-          clear(r)
-
+          clear(r),
+          replace((a && c && t && r) ? qslow_replace : nullptr),
+          removeLast((a && c && t && r) ? qslow_removeLast : nullptr)
     {}
-    QQmlListProperty(QObject *o, void *d, CountFunction c, AtFunction t)
+
+    QQmlListProperty(QObject *o, void *d, AppendFunction a, CountFunction c, AtFunction t,
+                     ClearFunction r, ReplaceFunction s, RemoveLastFunction p)
         : object(o),
           data(d),
-          append(nullptr),
-          count(c), at(t),
-          clear(nullptr)
+          append(a),
+          count(c),
+          at(t),
+          clear((!r && p && c) ? qslow_clear : r),
+          replace((!s && a && c && t && (r || p)) ? qslow_replace : s),
+          removeLast((!p && a && c && t && r) ? qslow_removeLast : p)
+    {}
+
+    QQmlListProperty(QObject *o, void *d, CountFunction c, AtFunction a)
+        : object(o), data(d), count(c), at(a)
     {}
+
     bool operator==(const QQmlListProperty &o) const {
         return object == o.object &&
                data == o.data &&
                append == o.append &&
                count == o.count &&
                at == o.at &&
-               clear == o.clear;
+               clear == o.clear &&
+               replace == o.replace &&
+               removeLast == o.removeLast;
     }
 
     QObject *object = nullptr;
     void *data = nullptr;
 
-    AppendFunction append;
-
-    CountFunction count;
-    AtFunction at;
-
-    ClearFunction clear;
-
-    void *dummy1 = nullptr;
-    void *dummy2 = nullptr;
+    AppendFunction append = nullptr;
+    CountFunction count = nullptr;
+    AtFunction at = nullptr;
+    ClearFunction clear = nullptr;
+    ReplaceFunction replace = nullptr;
+    RemoveLastFunction removeLast = nullptr;
 
 private:
     static void qlist_append(QQmlListProperty *p, T *v) {
@@ -123,6 +139,59 @@ private:
     static void qlist_clear(QQmlListProperty *p) {
         return reinterpret_cast<QList<T *> *>(p->data)->clear();
     }
+    static void qlist_replace(QQmlListProperty *p, int idx, T *v) {
+        return reinterpret_cast<QList<T *> *>(p->data)->replace(idx, v);
+    }
+    static void qlist_removeLast(QQmlListProperty *p) {
+        return reinterpret_cast<QList<T *> *>(p->data)->removeLast();
+    }
+
+    static void qslow_replace(QQmlListProperty<T> *list, int idx, T *v)
+    {
+        const int length = list->count(list);
+        if (idx < 0 || idx >= length)
+            return;
+
+        QVector<T *> stash;
+        if (list->clear != qslow_clear) {
+            stash.reserve(length);
+            for (int i = 0; i < length; ++i)
+                stash.append(i == idx ? v : list->at(list, i));
+            list->clear(list);
+            for (T *item : qAsConst(stash))
+                list->append(list, item);
+        } else {
+            stash.reserve(length - idx - 1);
+            for (int i = length - 1; i > idx; --i) {
+                stash.append(list->at(list, i));
+                list->removeLast(list);
+            }
+            list->removeLast(list);
+            list->append(list, v);
+            while (!stash.isEmpty())
+                list->append(list, stash.takeLast());
+        }
+    }
+
+    static void qslow_clear(QQmlListProperty<T> *list)
+    {
+        for (int i = 0, end = list->count(list); i < end; ++i)
+            list->removeLast(list);
+    }
+
+    static void qslow_removeLast(QQmlListProperty<T> *list)
+    {
+        const int length = list->count(list) - 1;
+        if (length < 0)
+            return;
+        QVector<T *> stash;
+        stash.reserve(length);
+        for (int i = 0; i < length; ++i)
+            stash.append(list->at(list, i));
+        list->clear(list);
+        for (T *item : qAsConst(stash))
+            list->append(list, item);
+    }
 };
 #endif
 
@@ -146,6 +215,8 @@ public:
     bool canAt() const;
     bool canClear() const;
     bool canCount() const;
+    bool canReplace() const;
+    bool canRemoveLast() const;
 
     bool isManipulable() const;
     bool isReadable() const;
@@ -154,6 +225,8 @@ public:
     QObject *at(int) const;
     bool clear() const;
     int count() const;
+    bool replace(int, QObject *) const;
+    bool removeLast() const;
 
 private:
     friend class QQmlListReferencePrivate;
diff --git a/src/qml/qml/qqmllistwrapper.cpp b/src/qml/qml/qqmllistwrapper.cpp
index 5349572921..e5c1cb04a9 100644
--- a/src/qml/qml/qqmllistwrapper.cpp
+++ b/src/qml/qml/qqmllistwrapper.cpp
@@ -119,11 +119,13 @@ ReturnedValue QmlListWrapper::virtualGet(const Managed *m, PropertyKey id, const
         if (hasProperty)
             *hasProperty = false;
         return Value::undefinedValue().asReturnedValue();
-    } else if (id.isString()) {
-        if (id == v4->id_length()->propertyKey() && !w->d()->object.isNull()) {
-            quint32 count = w->d()->property().count ? w->d()->property().count(&w->d()->property()) : 0;
-            return Value::fromUInt32(count).asReturnedValue();
-        }
+    }
+
+    if (id.isString() && id == v4->id_length()->propertyKey()) {
+        if (hasProperty)
+            *hasProperty = true;
+        quint32 count = w->d()->property().count ? w->d()->property().count(&w->d()->property()) : 0;
+        return Value::fromUInt32(count).asReturnedValue();
     }
 
     return Object::virtualGet(m, id, receiver, hasProperty);
@@ -131,12 +133,70 @@ ReturnedValue QmlListWrapper::virtualGet(const Managed *m, PropertyKey id, const
 
 bool QmlListWrapper::virtualPut(Managed *m, PropertyKey id, const Value &value, Value *receiver)
 {
-    // doesn't do anything. Should we throw?
-    Q_UNUSED(m);
-    Q_UNUSED(id);
-    Q_UNUSED(value);
-    Q_UNUSED(receiver);
-    return false;
+    Q_ASSERT(m->as<QmlListWrapper>());
+
+    const auto *w = static_cast<const QmlListWrapper *>(m);
+    QV4::ExecutionEngine *v4 = w->engine();
+
+    QQmlListProperty<QObject> *prop = &(w->d()->property());
+
+    if (id.isArrayIndex()) {
+        if (!prop->count || !prop->replace)
+            return false;
+
+        const uint index = id.asArrayIndex();
+        const int count = prop->count(prop);
+        if (count < 0 || index >= uint(count))
+            return false;
+
+        QV4::Scope scope(v4);
+        QV4::ScopedObject so(scope, value.toObject(scope.engine));
+        if (auto *wrapper = so->as<QV4::QObjectWrapper>()) {
+            prop->replace(prop, index, wrapper->object());
+            return true;
+        }
+
+        return false;
+    }
+
+    if (id.isString() && id == v4->id_length()->propertyKey()) {
+        if (!prop->count)
+            return false;
+
+        const quint32 count = prop->count(prop);
+
+        bool ok = false;
+        const uint newLength = value.asArrayLength(&ok);
+        if (!ok)
+            return false;
+
+        if (newLength == 0) {
+            if (!prop->clear)
+                return false;
+            prop->clear(prop);
+            return true;
+        }
+
+        if (newLength < count) {
+            if (!prop->removeLast)
+                return false;
+
+            for (uint i = newLength; i < count; ++i)
+                prop->removeLast(prop);
+
+            return true;
+        }
+
+        if (!prop->append)
+            return false;
+
+        for (uint i = count; i < newLength; ++i)
+            prop->append(prop, nullptr);
+
+        return true;
+    }
+
+    return Object::virtualPut(m, id, value, receiver);
 }
 
 struct QmlListWrapperOwnPropertyKeyIterator : ObjectOwnPropertyKeyIterator
diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index f506cdece3..76816618ac 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -531,7 +531,7 @@ QQmlType QQmlMetaType::registerCompositeType(const QQmlPrivate::RegisterComposit
     return QQmlType(priv);
 }
 
-QQmlMetaType::CompositeMetaTypeIds QQmlMetaType::registerInternalCompositeType(const QByteArray &className)
+CompositeMetaTypeIds QQmlMetaType::registerInternalCompositeType(const QByteArray &className)
 {
     QByteArray ptr = className + '*';
     QByteArray lst = "QQmlListProperty<" + className + '>';
@@ -555,7 +555,7 @@ QQmlMetaType::CompositeMetaTypeIds QQmlMetaType::registerInternalCompositeType(c
     return {ptr_type, lst_type};
 }
 
-void QQmlMetaType::unregisterInternalCompositeType(const QQmlMetaType::CompositeMetaTypeIds &typeIds)
+void QQmlMetaType::unregisterInternalCompositeType(const CompositeMetaTypeIds &typeIds)
 {
     QQmlMetaTypeDataPtr data;
     data->qmlLists.remove(typeIds.listId);
diff --git a/src/qml/qml/qqmlmetatype_p.h b/src/qml/qml/qqmlmetatype_p.h
index 80126cbffb..037cf89beb 100644
--- a/src/qml/qml/qqmlmetatype_p.h
+++ b/src/qml/qml/qqmlmetatype_p.h
@@ -63,6 +63,15 @@ class QQmlError;
 
 namespace QV4 { class ExecutableCompilationUnit; }
 
+struct CompositeMetaTypeIds
+{
+    int id = -1;
+    int listId = -1;
+    CompositeMetaTypeIds() = default;
+    CompositeMetaTypeIds(int id, int listId) : id(id), listId(listId) {}
+    bool isValid() const { return id != -1 && listId != -1; }
+};
+
 class Q_QML_PRIVATE_EXPORT QQmlMetaType
 {
 public:
@@ -80,18 +89,8 @@ public:
 
     static void unregisterType(int type);
 
-    struct CompositeMetaTypeIds
-    {
-        int id = -1;
-        int listId = -1;
-        CompositeMetaTypeIds() = default;
-        CompositeMetaTypeIds(int id, int listId) : id(id), listId(listId) {}
-        bool isValid() const { return id != -1 && listId != -1; }
-    };
-
     static CompositeMetaTypeIds registerInternalCompositeType(const QByteArray &className);
-    static void unregisterInternalCompositeType(const QQmlMetaType::CompositeMetaTypeIds &typeIds);
-
+    static void unregisterInternalCompositeType(const CompositeMetaTypeIds &typeIds);
     static void registerModule(const char *uri, int versionMajor, int versionMinor);
     static bool protectModule(const QString &uri, int majVersion);
 
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index d68ad69260..198ce98f2d 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -62,6 +62,7 @@
 #include <QScopedValueRollback>
 
 #include <qtqml_tracepoints_p.h>
+#include <QScopedValueRollback>
 
 QT_USE_NAMESPACE
 
@@ -77,9 +78,9 @@ QQmlObjectCreator::QQmlObjectCreator(QQmlContextData *parentContext, const QQmlR
     init(parentContext);
 
     sharedState->componentAttached = nullptr;
-    sharedState->allCreatedBindings.allocate(compilationUnit->totalBindingsCount);
-    sharedState->allParserStatusCallbacks.allocate(compilationUnit->totalParserStatusCount);
-    sharedState->allCreatedObjects.allocate(compilationUnit->totalObjectCount);
+    sharedState->allCreatedBindings.allocate(compilationUnit->totalBindingsCount());
+    sharedState->allParserStatusCallbacks.allocate(compilationUnit->totalParserStatusCount());
+    sharedState->allCreatedObjects.allocate(compilationUnit->totalObjectCount());
     sharedState->allJavaScriptObjects = nullptr;
     sharedState->creationContext = creationContext;
     sharedState->rootContext = nullptr;
@@ -87,7 +88,7 @@ QQmlObjectCreator::QQmlObjectCreator(QQmlContextData *parentContext, const QQmlR
 
     if (auto profiler = QQmlEnginePrivate::get(engine)->profiler) {
         Q_QML_PROFILE_IF_ENABLED(QQmlProfilerDefinitions::ProfileCreating, profiler,
-                sharedState->profiler.init(profiler, compilationUnit->totalParserStatusCount));
+                sharedState->profiler.init(profiler, compilationUnit->totalParserStatusCount()));
     } else {
         Q_UNUSED(profiler);
     }
@@ -145,7 +146,7 @@ QQmlObjectCreator::~QQmlObjectCreator()
     }
 }
 
-QObject *QQmlObjectCreator::create(int subComponentIndex, QObject *parent, QQmlInstantiationInterrupt *interrupt)
+QObject *QQmlObjectCreator::create(int subComponentIndex, QObject *parent, QQmlInstantiationInterrupt *interrupt, int flags)
 {
     if (phase == CreatingObjectsPhase2) {
         phase = ObjectsCreated;
@@ -159,14 +160,20 @@ QObject *QQmlObjectCreator::create(int subComponentIndex, QObject *parent, QQmlI
     if (subComponentIndex == -1) {
         objectToCreate = /*root object*/0;
     } else {
-        const QV4::CompiledData::Object *compObj = compilationUnit->objectAt(subComponentIndex);
-        objectToCreate = compObj->bindingTable()->value.objectIndex;
+        Q_ASSERT(subComponentIndex >= 0);
+        if (flags & CreationFlags::InlineComponent) {
+            objectToCreate = subComponentIndex;
+        } else {
+            Q_ASSERT(flags & CreationFlags::NormalObject);
+            const QV4::CompiledData::Object *compObj = compilationUnit->objectAt(subComponentIndex);
+            objectToCreate = compObj->bindingTable()->value.objectIndex;
+        }
     }
 
     context = new QQmlContextData;
     context->isInternal = true;
     context->imports = compilationUnit->typeNameCache;
-    context->initFromTypeCompilationUnit(compilationUnit, subComponentIndex);
+    context->initFromTypeCompilationUnit(compilationUnit, flags & CreationFlags::NormalObject ? subComponentIndex : -1);
     context->setParent(parentContext);
 
     if (!sharedState->rootContext) {
@@ -179,7 +186,7 @@ QObject *QQmlObjectCreator::create(int subComponentIndex, QObject *parent, QQmlI
 
     Q_ASSERT(sharedState->allJavaScriptObjects || topLevelCreator);
     if (topLevelCreator)
-        sharedState->allJavaScriptObjects = scope.alloc(compilationUnit->totalObjectCount);
+        sharedState->allJavaScriptObjects = scope.alloc(compilationUnit->totalObjectCount());
 
     if (subComponentIndex == -1 && compilationUnit->dependentScripts.count()) {
         QV4::ScopedObject scripts(scope, v4->newArrayObject(compilationUnit->dependentScripts.count()));
@@ -231,6 +238,9 @@ void QQmlObjectCreator::beginPopulateDeferred(QQmlContextData *newContext)
 
     Q_ASSERT(topLevelCreator);
     Q_ASSERT(!sharedState->allJavaScriptObjects);
+
+    QV4::Scope valueScope(v4);
+    sharedState->allJavaScriptObjects = valueScope.alloc(compilationUnit->totalObjectCount());
 }
 
 void QQmlObjectCreator::populateDeferred(QObject *instance, int deferredIndex,
@@ -248,7 +258,7 @@ void QQmlObjectCreator::populateDeferred(QObject *instance, int deferredIndex,
 
     QV4::Scope valueScope(v4);
     QScopedValueRollback<QV4::Value*> jsObjectGuard(sharedState->allJavaScriptObjects,
-                                                    valueScope.alloc(compilationUnit->totalObjectCount));
+                                                    valueScope.alloc(compilationUnit->totalObjectCount()));
 
     Q_ASSERT(topLevelCreator);
     QV4::QmlContext *qmlContext = static_cast<QV4::QmlContext *>(valueScope.alloc());
@@ -263,7 +273,6 @@ void QQmlObjectCreator::populateDeferred(QObject *instance, int deferredIndex,
 
     const QV4::CompiledData::Object *obj = compilationUnit->objectAt(_compiledObjectIndex);
     qSwap(_compiledObject, obj);
-
     qSwap(_ddata, declarativeData);
     qSwap(_bindingTarget, bindingTarget);
     qSwap(_vmeMetaObject, vmeMetaObject);
@@ -414,25 +423,25 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         }
     }
     break;
-    case QVariant::String: {
+    case QMetaType::QString: {
         assertOrNull(binding->evaluatesToString());
         QString value = compilationUnit->bindingValueAsString(binding);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::StringList: {
+    case QMetaType::QStringList: {
         assertOrNull(binding->evaluatesToString());
         QStringList value(compilationUnit->bindingValueAsString(binding));
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::ByteArray: {
+    case QMetaType::QByteArray: {
         assertType(QV4::CompiledData::Binding::Type_String);
         QByteArray value(compilationUnit->bindingValueAsString(binding).toUtf8());
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Url: {
+    case QMetaType::QUrl: {
         assertType(QV4::CompiledData::Binding::Type_String);
         QString string = compilationUnit->bindingValueAsString(binding);
         // Encoded dir-separators defeat QUrl processing - decode them first
@@ -444,7 +453,7 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::UInt: {
+    case QMetaType::UInt: {
         assertType(QV4::CompiledData::Binding::Type_Number);
         double d = compilationUnit->bindingValueAsNumber(binding);
         uint value = uint(d);
@@ -452,7 +461,7 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         break;
     }
     break;
-    case QVariant::Int: {
+    case QMetaType::Int: {
         assertType(QV4::CompiledData::Binding::Type_Number);
         double d = compilationUnit->bindingValueAsNumber(binding);
         int value = int(d);
@@ -466,13 +475,13 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Double: {
+    case QMetaType::Double: {
         assertType(QV4::CompiledData::Binding::Type_Number);
         double value = compilationUnit->bindingValueAsNumber(binding);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Color: {
+    case QMetaType::QColor: {
         bool ok = false;
         uint colorValue = QQmlStringConverters::rgbaFromString(compilationUnit->bindingValueAsString(binding), &ok);
         assertOrNull(ok);
@@ -483,21 +492,21 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
     }
     break;
 #if QT_CONFIG(datestring)
-    case QVariant::Date: {
+    case QMetaType::QDate: {
         bool ok = false;
         QDate value = QQmlStringConverters::dateFromString(compilationUnit->bindingValueAsString(binding), &ok);
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Time: {
+    case QMetaType::QTime: {
         bool ok = false;
         QTime value = QQmlStringConverters::timeFromString(compilationUnit->bindingValueAsString(binding), &ok);
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::DateTime: {
+    case QMetaType::QDateTime: {
         bool ok = false;
         QDateTime value = QQmlStringConverters::dateTimeFromString(compilationUnit->bindingValueAsString(binding), &ok);
         // ### VME compatibility :(
@@ -511,55 +520,55 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
     }
     break;
 #endif // datestring
-    case QVariant::Point: {
+    case QMetaType::QPoint: {
         bool ok = false;
         QPoint value = QQmlStringConverters::pointFFromString(compilationUnit->bindingValueAsString(binding), &ok).toPoint();
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::PointF: {
+    case QMetaType::QPointF: {
         bool ok = false;
         QPointF value = QQmlStringConverters::pointFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Size: {
+    case QMetaType::QSize: {
         bool ok = false;
         QSize value = QQmlStringConverters::sizeFFromString(compilationUnit->bindingValueAsString(binding), &ok).toSize();
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::SizeF: {
+    case QMetaType::QSizeF: {
         bool ok = false;
         QSizeF value = QQmlStringConverters::sizeFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Rect: {
+    case QMetaType::QRect: {
         bool ok = false;
         QRect value = QQmlStringConverters::rectFFromString(compilationUnit->bindingValueAsString(binding), &ok).toRect();
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::RectF: {
+    case QMetaType::QRectF: {
         bool ok = false;
         QRectF value = QQmlStringConverters::rectFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         assertOrNull(ok);
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Bool: {
+    case QMetaType::Bool: {
         assertType(QV4::CompiledData::Binding::Type_Boolean);
         bool value = binding->valueAsBoolean();
         property->writeProperty(_qobject, &value, propertyWriteFlags);
     }
     break;
-    case QVariant::Vector2D: {
+    case QMetaType::QVector2D: {
         struct {
             float xp;
             float yp;
@@ -570,7 +579,7 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         property->writeProperty(_qobject, &vec, propertyWriteFlags);
     }
     break;
-    case QVariant::Vector3D: {
+    case QMetaType::QVector3D: {
         struct {
             float xp;
             float yp;
@@ -582,7 +591,7 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         property->writeProperty(_qobject, &vec, propertyWriteFlags);
     }
     break;
-    case QVariant::Vector4D: {
+    case QMetaType::QVector4D: {
         struct {
             float xp;
             float yp;
@@ -595,7 +604,7 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         property->writeProperty(_qobject, &vec, propertyWriteFlags);
     }
     break;
-    case QVariant::Quaternion: {
+    case QMetaType::QQuaternion: {
         struct {
             float wp;
             float xp;
@@ -608,7 +617,7 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         property->writeProperty(_qobject, &vec, propertyWriteFlags);
     }
     break;
-    case QVariant::RegExp:
+    case QMetaType::QRegExp:
         assertOrNull(!"not possible");
         break;
     default: {
@@ -673,7 +682,7 @@ void QQmlObjectCreator::setPropertyValue(const QQmlPropertyData *property, const
         QVariant value = (*converter)(stringValue);
 
         QMetaProperty metaProperty = _qobject->metaObject()->property(property->coreIndex());
-        if (value.isNull() || ((int)metaProperty.type() != property->propType() && metaProperty.userType() != property->propType())) {
+        if (value.isNull() || metaProperty.userType() != property->propType()) {
             recordError(binding->location, tr("Cannot assign value %1 to property %2").arg(stringValue).arg(QString::fromUtf8(metaProperty.name())));
             break;
         }
@@ -1172,7 +1181,7 @@ QObject *QQmlObjectCreator::createInstance(int index, QObject *parent, bool isCo
         Q_ASSERT(typeRef);
         installPropertyCache = !typeRef->isFullyDynamicType;
         QQmlType type = typeRef->type;
-        if (type.isValid()) {
+        if (type.isValid() && !type.isInlineComponentType()) {
             typeName = type.qmlTypeName();
 
             void *ddataMemory = nullptr;
@@ -1206,17 +1215,31 @@ QObject *QQmlObjectCreator::createInstance(int index, QObject *parent, bool isCo
         } else {
             Q_ASSERT(typeRef->compilationUnit);
             typeName = typeRef->compilationUnit->fileName();
-            if (typeRef->compilationUnit->unitData()->isSingleton())
+            // compilation unit is shared between root type and its inline component types
+            // so isSingleton errorneously returns true for inline components
+            if (typeRef->compilationUnit->unitData()->isSingleton() && !type.isInlineComponentType())
             {
                 recordError(obj->location, tr("Composite Singleton Type %1 is not creatable").arg(stringAt(obj->inheritedTypeNameIndex)));
                 return nullptr;
             }
 
-            QQmlObjectCreator subCreator(context, typeRef->compilationUnit, sharedState.data());
-            instance = subCreator.create();
-            if (!instance) {
-                errors += subCreator.errors;
-                return nullptr;
+
+            if (!type.isInlineComponentType()) {
+                QQmlObjectCreator subCreator(context, typeRef->compilationUnit, sharedState.data());
+                instance = subCreator.create();
+                if (!instance) {
+                    errors += subCreator.errors;
+                    return nullptr;
+                }
+            } else {
+                int subObjectId = type.inlineComponendId();
+                QScopedValueRollback<int> rollback {typeRef->compilationUnit->icRoot, subObjectId};
+                QQmlObjectCreator subCreator(context, typeRef->compilationUnit, sharedState.data());
+                instance = subCreator.create(subObjectId, nullptr, nullptr, CreationFlags::InlineComponent);
+                if (!instance) {
+                    errors += subCreator.errors;
+                    return nullptr;
+                }
             }
         }
         if (instance->isWidgetType()) {
diff --git a/src/qml/qml/qqmlobjectcreator_p.h b/src/qml/qml/qqmlobjectcreator_p.h
index 8b6cb67341..f8ad90be15 100644
--- a/src/qml/qml/qqmlobjectcreator_p.h
+++ b/src/qml/qml/qqmlobjectcreator_p.h
@@ -111,7 +111,8 @@ public:
     QQmlObjectCreator(QQmlContextData *parentContext, const QQmlRefPointer<QV4::ExecutableCompilationUnit> &compilationUnit, QQmlContextData *creationContext, QQmlIncubatorPrivate  *incubator = nullptr);
     ~QQmlObjectCreator();
 
-    QObject *create(int subComponentIndex = -1, QObject *parent = nullptr, QQmlInstantiationInterrupt *interrupt = nullptr);
+    enum CreationFlags { NormalObject = 1, InlineComponent = 2 };
+    QObject *create(int subComponentIndex = -1, QObject *parent = nullptr, QQmlInstantiationInterrupt *interrupt = nullptr, int flags = NormalObject);
 
     bool populateDeferredProperties(QObject *instance, const QQmlData::DeferredData *deferredData);
 
diff --git a/src/qml/qml/qqmlproperty.cpp b/src/qml/qml/qqmlproperty.cpp
index 871bec1c17..93020661e2 100644
--- a/src/qml/qml/qqmlproperty.cpp
+++ b/src/qml/qml/qqmlproperty.cpp
@@ -471,7 +471,7 @@ QQmlPropertyPrivate::propertyTypeCategory() const
         return QQmlProperty::Normal;
     } else if (type & QQmlProperty::Property) {
         int type = propertyType();
-        if (type == QVariant::Invalid)
+        if (type == QMetaType::UnknownType)
             return QQmlProperty::InvalidCategory;
         else if (QQmlValueTypeFactory::isValueType((uint)type))
             return QQmlProperty::Normal;
@@ -526,7 +526,7 @@ bool QQmlProperty::operator==(const QQmlProperty &other) const
 */
 int QQmlProperty::propertyType() const
 {
-    return d ? d->propertyType() : int(QVariant::Invalid);
+    return d ? d->propertyType() : int(QMetaType::UnknownType);
 }
 
 bool QQmlPropertyPrivate::isValueType() const
@@ -542,7 +542,7 @@ int QQmlPropertyPrivate::propertyType() const
     } else if (type & QQmlProperty::Property) {
         return core.propType();
     } else {
-        return QVariant::Invalid;
+        return QMetaType::UnknownType;
     }
 }
 
@@ -1133,7 +1133,7 @@ bool QQmlPropertyPrivate::writeEnumProperty(const QMetaProperty &prop, int idx,
     QVariant v = value;
     if (prop.isEnumType()) {
         QMetaEnum menum = prop.enumerator();
-        if (v.userType() == QVariant::String
+        if (v.userType() == QMetaType::QString
 #ifdef QT3_SUPPORT
             || v.userType() == QVariant::CString
 #endif
@@ -1145,13 +1145,13 @@ bool QQmlPropertyPrivate::writeEnumProperty(const QMetaProperty &prop, int idx,
                 v = QVariant(menum.keyToValue(value.toByteArray(), &ok));
             if (!ok)
                 return false;
-        } else if (v.userType() != QVariant::Int && v.userType() != QVariant::UInt) {
+        } else if (v.userType() != QMetaType::Int && v.userType() != QMetaType::UInt) {
             int enumMetaTypeId = QMetaType::type(QByteArray(menum.scope() + QByteArray("::") + menum.name()));
             if ((enumMetaTypeId == QMetaType::UnknownType) || (v.userType() != enumMetaTypeId) || !v.constData())
                 return false;
             v = QVariant(*reinterpret_cast<const int *>(v.constData()));
         }
-        v.convert(QVariant::Int);
+        v.convert(QMetaType::Int);
     }
 
     // the status variable is changed by qt_metacall to indicate what it did
@@ -1206,17 +1206,17 @@ bool QQmlPropertyPrivate::write(QObject *object,
         QMetaProperty prop = object->metaObject()->property(property.coreIndex());
         QVariant v = value;
         // Enum values come through the script engine as doubles
-        if (variantType == QVariant::Double) {
+        if (variantType == QMetaType::Double) {
             double integral;
             double fractional = std::modf(value.toDouble(), &integral);
             if (qFuzzyIsNull(fractional))
-                v.convert(QVariant::Int);
+                v.convert(QMetaType::Int);
         }
         return writeEnumProperty(prop, property.coreIndex(), object, v, flags);
     }
 
     QQmlEnginePrivate *enginePriv = QQmlEnginePrivate::get(context);
-    const bool isUrl = propertyType == QVariant::Url; // handled separately
+    const bool isUrl = propertyType == QMetaType::QUrl; // handled separately
 
     // The cases below are in approximate order of likelyhood:
     if (propertyType == variantType && !isUrl && propertyType != qMetaTypeId<QList<QUrl>>() && !property.isQList()) {
@@ -1249,7 +1249,7 @@ bool QQmlPropertyPrivate::write(QObject *object,
         } else {
             return false;
         }
-    } else if (value.canConvert(propertyType) && !isUrl && variantType != QVariant::String && propertyType != qMetaTypeId<QList<QUrl>>() && !property.isQList()) {
+    } else if (value.canConvert(propertyType) && !isUrl && variantType != QMetaType::QString && propertyType != qMetaTypeId<QList<QUrl>>() && !property.isQList()) {
         // common cases:
         switch (propertyType) {
         case QMetaType::Bool: {
@@ -1282,14 +1282,14 @@ bool QQmlPropertyPrivate::write(QObject *object,
         return property.writeProperty(object, const_cast<QVariant *>(&value), flags);
     } else if (isUrl) {
         QUrl u;
-        if (variantType == QVariant::Url) {
+        if (variantType == QMetaType::QUrl) {
             u = value.toUrl();
-        } else if (variantType == QVariant::ByteArray) {
+        } else if (variantType == QMetaType::QByteArray) {
             QString input(QString::fromUtf8(value.toByteArray()));
             // Encoded dir-separators defeat QUrl processing - decode them first
             input.replace(QLatin1String("%2f"), QLatin1String("/"), Qt::CaseInsensitive);
             u = QUrl(input);
-        } else if (variantType == QVariant::String) {
+        } else if (variantType == QMetaType::QString) {
             QString input(value.toString());
             // Encoded dir-separators defeat QUrl processing - decode them first
             input.replace(QLatin1String("%2f"), QLatin1String("/"), Qt::CaseInsensitive);
@@ -1355,7 +1355,7 @@ bool QQmlPropertyPrivate::write(QObject *object,
 
         bool ok = false;
         QVariant v;
-        if (variantType == QVariant::String)
+        if (variantType == QMetaType::QString)
             v = QQmlStringConverters::variantFromString(value.toString(), propertyType, &ok);
 
         if (!ok) {
@@ -1368,8 +1368,8 @@ bool QQmlPropertyPrivate::write(QObject *object,
                 // successful conversion.
                 Q_ASSERT(v.userType() == propertyType);
                 ok = true;
-            } else if (static_cast<uint>(propertyType) >= QVariant::UserType &&
-                       variantType == QVariant::String) {
+            } else if (static_cast<uint>(propertyType) >= QMetaType::User &&
+                       variantType == QMetaType::QString) {
                 QQmlMetaType::StringConverter con = QQmlMetaType::customStringConverter(propertyType);
                 if (con) {
                     v = con(value.toString());
@@ -1383,28 +1383,28 @@ bool QQmlPropertyPrivate::write(QObject *object,
             // to a sequence type property (eg, an int to a QList<int> property).
             // or that we encountered an interface type
             // Note that we've already handled single-value assignment to QList<QUrl> properties.
-            if (variantType == QVariant::Int && propertyType == qMetaTypeId<QList<int> >()) {
+            if (variantType == QMetaType::Int && propertyType == qMetaTypeId<QList<int> >()) {
                 QList<int> list;
                 list << value.toInt();
                 v = QVariant::fromValue<QList<int> >(list);
                 ok = true;
-            } else if ((variantType == QVariant::Double || variantType == QVariant::Int)
+            } else if ((variantType == QMetaType::Double || variantType == QMetaType::Int)
                        && (propertyType == qMetaTypeId<QList<qreal> >())) {
                 QList<qreal> list;
                 list << value.toReal();
                 v = QVariant::fromValue<QList<qreal> >(list);
                 ok = true;
-            } else if (variantType == QVariant::Bool && propertyType == qMetaTypeId<QList<bool> >()) {
+            } else if (variantType == QMetaType::Bool && propertyType == qMetaTypeId<QList<bool> >()) {
                 QList<bool> list;
                 list << value.toBool();
                 v = QVariant::fromValue<QList<bool> >(list);
                 ok = true;
-            } else if (variantType == QVariant::String && propertyType == qMetaTypeId<QList<QString> >()) {
+            } else if (variantType == QMetaType::QString && propertyType == qMetaTypeId<QList<QString> >()) {
                 QList<QString> list;
                 list << value.toString();
                 v = QVariant::fromValue<QList<QString> >(list);
                 ok = true;
-            } else if (variantType == QVariant::String && propertyType == qMetaTypeId<QStringList>()) {
+            } else if (variantType == QMetaType::QString && propertyType == qMetaTypeId<QStringList>()) {
                 QStringList list;
                 list << value.toString();
                 v = QVariant::fromValue<QStringList>(list);
diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index 6336ff28b3..c4afbbd598 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -71,10 +71,10 @@ static QQmlPropertyData::Flags fastFlagsForProperty(const QMetaProperty &p)
 {
     QQmlPropertyData::Flags flags;
 
-    flags.isConstant = p.isConstant();
-    flags.isWritable = p.isWritable();
-    flags.isResettable = p.isResettable();
-    flags.isFinal = p.isFinal();
+    flags.setIsConstant(p.isConstant());
+    flags.setIsWritable(p.isWritable());
+    flags.setIsResettable(p.isResettable());
+    flags.setIsFinal(p.isFinal());
 
     if (p.isEnumType())
         flags.type = QQmlPropertyData::Flags::EnumType;
@@ -92,7 +92,7 @@ static void flagsForPropertyType(int propType, QQmlPropertyData::Flags &flags)
         flags.type = QQmlPropertyData::Flags::QObjectDerivedType;
     } else if (propType == QMetaType::QVariant) {
         flags.type = QQmlPropertyData::Flags::QVariantType;
-    } else if (propType < static_cast<int>(QVariant::UserType)) {
+    } else if (propType < static_cast<int>(QMetaType::User)) {
         // nothing to do
     } else if (propType == qMetaTypeId<QQmlBinding *>()) {
         flags.type = QQmlPropertyData::Flags::QmlBindingType;
@@ -136,14 +136,14 @@ static void populate(QQmlPropertyData *data, const QMetaProperty &p)
 void QQmlPropertyData::lazyLoad(const QMetaProperty &p)
 {
     populate(this, p);
-    int type = static_cast<int>(p.type());
+    int type = static_cast<int>(p.userType());
     if (type == QMetaType::QObjectStar) {
         setPropType(type);
         m_flags.type = Flags::QObjectDerivedType;
     } else if (type == QMetaType::QVariant) {
         setPropType(type);
         m_flags.type = Flags::QVariantType;
-    } else if (type == QVariant::UserType || type == -1) {
+    } else if (type >= QMetaType::User || type == 0) {
         m_flags.notFullyResolved = true;
     } else {
         setPropType(type);
@@ -166,21 +166,21 @@ void QQmlPropertyData::load(const QMetaMethod &m)
 
     m_flags.type = Flags::FunctionType;
     if (m.methodType() == QMetaMethod::Signal) {
-        m_flags.isSignal = true;
+        m_flags.setIsSignal(true);
     } else if (m.methodType() == QMetaMethod::Constructor) {
-        m_flags.isConstructor = true;
+        m_flags.setIsConstructor(true);
         setPropType(QMetaType::QObjectStar);
     }
 
     const int paramCount = m.parameterCount();
     if (paramCount) {
-        m_flags.hasArguments = true;
+        m_flags.setHasArguments(true);
         if ((paramCount == 1) && (m.parameterTypes().constFirst() == "QQmlV4Function*"))
-            m_flags.isV4Function = true;
+            m_flags.setIsV4Function(true);
     }
 
     if (m.attributes() & QMetaMethod::Cloned)
-        m_flags.isCloned = true;
+        m_flags.setIsCloned(true);
 
     Q_ASSERT(m.revision() <= Q_INT16_MAX);
     setRevision(m.revision());
@@ -314,13 +314,13 @@ void QQmlPropertyCache::appendSignal(const QString &name, QQmlPropertyData::Flag
                                      const QList<QByteArray> &names)
 {
     QQmlPropertyData data;
-    data.setPropType(QVariant::Invalid);
+    data.setPropType(QMetaType::UnknownType);
     data.setCoreIndex(coreIndex);
     data.setFlags(flags);
     data.setArguments(nullptr);
 
     QQmlPropertyData handler = data;
-    handler.m_flags.isSignalHandler = true;
+    handler.m_flags.setIsSignalHandler(true);
 
     if (types) {
         int argumentCount = *types;
@@ -519,7 +519,7 @@ void QQmlPropertyCache::append(const QMetaObject *metaObject,
             data->setFlags(methodFlags);
 
         data->lazyLoad(m);
-        data->m_flags.isDirect = !dynamicMetaObject;
+        data->m_flags.setIsDirect(!dynamicMetaObject);
 
         Q_ASSERT((allowedRevisionCache.count() - 1) < Q_INT16_MAX);
         data->setMetaObjectOffset(allowedRevisionCache.count() - 1);
@@ -527,7 +527,7 @@ void QQmlPropertyCache::append(const QMetaObject *metaObject,
         if (data->isSignal()) {
             sigdata = &signalHandlerIndexCache[signalHandlerIndex - signalHandlerIndexCacheStart];
             *sigdata = *data;
-            sigdata->m_flags.isSignalHandler = true;
+            sigdata->m_flags.setIsSignalHandler(true);
         }
 
         QQmlPropertyData *old = nullptr;
@@ -569,7 +569,7 @@ void QQmlPropertyCache::append(const QMetaObject *metaObject,
         if (old) {
             // We only overload methods in the same class, exactly like C++
             if (old->isFunction() && old->coreIndex() >= methodOffset)
-                data->m_flags.isOverload = true;
+                data->m_flags.setIsOverload(true);
 
             data->markAsOverrideOf(old);
         }
@@ -600,7 +600,7 @@ void QQmlPropertyCache::append(const QMetaObject *metaObject,
         data->lazyLoad(p);
         data->setTypeMinorVersion(typeMinorVersion);
 
-        data->m_flags.isDirect = !dynamicMetaObject;
+        data->m_flags.setIsDirect(!dynamicMetaObject);
 
         Q_ASSERT((allowedRevisionCache.count() - 1) < Q_INT16_MAX);
         data->setMetaObjectOffset(allowedRevisionCache.count() - 1);
@@ -626,7 +626,7 @@ void QQmlPropertyCache::append(const QMetaObject *metaObject,
         }
 
         if (isGadget) // always dispatch over a 'normal' meta-call so the QQmlValueType can intercept
-            data->m_flags.isDirect = false;
+            data->m_flags.setIsDirect(false);
         else
             data->trySetStaticMetaCallFunction(metaObject->d.static_metacall, ii - propOffset);
         if (old)
@@ -849,7 +849,7 @@ void QQmlPropertyData::markAsOverrideOf(QQmlPropertyData *predecessor)
     setOverrideIndexIsProperty(!predecessor->isFunction());
     setOverrideIndex(predecessor->coreIndex());
 
-    predecessor->m_flags.isOverridden = true;
+    predecessor->m_flags.setIsOverridden(true);
 }
 
 QQmlPropertyCacheMethodArguments *QQmlPropertyCache::createArgumentsObject(int argc, const QList<QByteArray> &names)
diff --git a/src/qml/qml/qqmlpropertycachecreator_p.h b/src/qml/qml/qqmlpropertycachecreator_p.h
index 8571b0c9b3..a050a0bf0a 100644
--- a/src/qml/qml/qqmlpropertycachecreator_p.h
+++ b/src/qml/qml/qqmlpropertycachecreator_p.h
@@ -55,6 +55,10 @@
 #include <private/qqmlmetaobject_p.h>
 #include <private/qqmlpropertyresolver_p.h>
 #include <private/qqmltypedata_p.h>
+#include <private/inlinecomponentutils_p.h>
+
+#include <QScopedValueRollback>
+#include <vector>
 
 QT_BEGIN_NAMESPACE
 
@@ -115,8 +119,12 @@ public:
 
     QQmlJS::DiagnosticMessage buildMetaObjects();
 
+    enum class VMEMetaObjectIsRequired {
+        Maybe,
+        Always
+    };
 protected:
-    QQmlJS::DiagnosticMessage buildMetaObjectRecursively(int objectIndex, const QQmlBindingInstantiationContext &context);
+    QQmlJS::DiagnosticMessage buildMetaObjectRecursively(int objectIndex, const QQmlBindingInstantiationContext &context, VMEMetaObjectIsRequired isVMERequired);
     QQmlRefPointer<QQmlPropertyCache> propertyCacheForObject(const CompiledObject *obj, const QQmlBindingInstantiationContext &context, QQmlJS::DiagnosticMessage *error) const;
     QQmlJS::DiagnosticMessage createMetaObject(int objectIndex, const CompiledObject *obj, const QQmlRefPointer<QQmlPropertyCache> &baseTypeCache);
 
@@ -129,7 +137,8 @@ protected:
     const QQmlImports * const imports;
     QQmlPropertyCacheVector *propertyCaches;
     QQmlPendingGroupPropertyBindings *pendingGroupPropertyBindings;
-    const QByteArray typeClassName;
+    QByteArray typeClassName; // not const as we temporarily chang it for inline components
+    unsigned int currentRoot; // set to objectID of inline component root when handling inline components
 };
 
 template <typename ObjectContainer>
@@ -151,12 +160,59 @@ inline QQmlPropertyCacheCreator<ObjectContainer>::QQmlPropertyCacheCreator(QQmlP
 template <typename ObjectContainer>
 inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::buildMetaObjects()
 {
+    using namespace icutils;
     QQmlBindingInstantiationContext context;
-    return buildMetaObjectRecursively(/*root object*/0, context);
+
+    // get a list of all inline components
+    using InlineComponent = typename std::remove_reference<decltype (*(std::declval<CompiledObject>().inlineComponentsBegin()))>::type;
+    std::vector<InlineComponent> allICs {};
+    for (int i=0; i != objectContainer->objectCount(); ++i) {
+        const CompiledObject *obj = objectContainer->objectAt(i);
+        for (auto it = obj->inlineComponentsBegin(); it != obj->inlineComponentsEnd(); ++it) {
+            allICs.push_back(*it);
+        }
+    }
+
+    // create a graph on inline components referencing inline components
+    std::vector<Node> nodes;
+    nodes.resize(allICs.size());
+    std::iota(nodes.begin(), nodes.end(), 0);
+    AdjacencyList adjacencyList;
+    adjacencyList.resize(nodes.size());
+    fillAdjacencyListForInlineComponents(objectContainer, adjacencyList, nodes, allICs);
+
+    bool hasCycle = false;
+    auto nodesSorted = topoSort(nodes, adjacencyList, hasCycle);
+
+    if (hasCycle) {
+        QQmlJS::DiagnosticMessage diag;
+        diag.message = QLatin1String("Inline components form a cycle!");
+        return diag;
+    }
+
+    // create meta objects for inline components before compiling actual root component
+    for (auto nodeIt = nodesSorted.rbegin(); nodeIt != nodesSorted.rend(); ++nodeIt) {
+        const auto &ic = allICs[nodeIt->index];
+        QV4::ResolvedTypeReference *typeRef = objectContainer->resolvedType(ic.nameIndex);
+        Q_ASSERT(propertyCaches->at(ic.objectIndex) == nullptr);
+        Q_ASSERT(typeRef->typePropertyCache.isNull()); // not set yet
+
+        QByteArray icTypeName { objectContainer->stringAt(ic.nameIndex).toUtf8() };
+        QScopedValueRollback<QByteArray> nameChange {typeClassName, icTypeName};
+        QScopedValueRollback<unsigned int> rootChange {currentRoot, ic.objectIndex};
+        QQmlJS::DiagnosticMessage diag = buildMetaObjectRecursively(ic.objectIndex, context, VMEMetaObjectIsRequired::Always);
+        if (diag.isValid()) {
+            return diag;
+        }
+        typeRef->typePropertyCache = propertyCaches->at(ic.objectIndex);
+        Q_ASSERT(!typeRef->typePropertyCache.isNull());
+    }
+
+    return buildMetaObjectRecursively(/*root object*/0, context, VMEMetaObjectIsRequired::Maybe);
 }
 
 template <typename ObjectContainer>
-inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::buildMetaObjectRecursively(int objectIndex, const QQmlBindingInstantiationContext &context)
+inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::buildMetaObjectRecursively(int objectIndex, const QQmlBindingInstantiationContext &context, VMEMetaObjectIsRequired isVMERequired)
 {
     auto isAddressable = [](const QUrl &url) {
         const QString fileName = url.fileName();
@@ -164,7 +220,7 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::buil
     };
 
     const CompiledObject *obj = objectContainer->objectAt(objectIndex);
-    bool needVMEMetaObject = obj->propertyCount() != 0 || obj->aliasCount() != 0
+    bool needVMEMetaObject = isVMERequired == VMEMetaObjectIsRequired::Always || obj->propertyCount() != 0 || obj->aliasCount() != 0
             || obj->signalCount() != 0 || obj->functionCount() != 0 || obj->enumCount() != 0
             || (((obj->flags & QV4::CompiledData::Object::IsComponent)
                  || (objectIndex == 0 && isAddressable(objectContainer->url())))
@@ -230,7 +286,7 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::buil
                 if (!context.resolveInstantiatingProperty())
                     pendingGroupPropertyBindings->append(context);
 
-                QQmlJS::DiagnosticMessage error = buildMetaObjectRecursively(binding->value.objectIndex, context);
+                QQmlJS::DiagnosticMessage error = buildMetaObjectRecursively(binding->value.objectIndex, context, VMEMetaObjectIsRequired::Maybe);
                 if (error.isValid())
                     return error;
             }
@@ -247,6 +303,7 @@ inline QQmlRefPointer<QQmlPropertyCache> QQmlPropertyCacheCreator<ObjectContaine
         return context.instantiatingPropertyCache(enginePrivate);
     } else if (obj->inheritedTypeNameIndex != 0) {
         auto *typeRef = objectContainer->resolvedType(obj->inheritedTypeNameIndex);
+        QQmlType qmltype = typeRef->type;
         Q_ASSERT(typeRef);
 
         if (typeRef->isFullyDynamicType) {
@@ -298,7 +355,7 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::crea
 
     QByteArray newClassName;
 
-    if (objectIndex == /*root object*/0) {
+    if (objectIndex == /*root object*/0 || int(currentRoot) == objectIndex) {
         newClassName = typeClassName;
     }
     if (newClassName.isEmpty()) {
@@ -428,7 +485,7 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::crea
 
         auto flags = QQmlPropertyData::defaultSignalFlags();
         if (paramCount)
-            flags.hasArguments = true;
+            flags.setHasArguments(true);
 
         QString signalName = stringAt(s->nameIndex);
         if (seenSignals.contains(signalName))
@@ -457,7 +514,7 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::crea
         auto formal = function->formalsBegin();
         auto end = function->formalsEnd();
         for ( ; formal != end; ++formal) {
-            flags.hasArguments = true;
+            flags.setHasArguments(true);
             parameterNames << stringAt(formal->nameIndex).toUtf8();
             int type = metaTypeForParameter(formal->type);
             if (type == QMetaType::UnknownType)
@@ -504,18 +561,31 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::crea
                 return qQmlCompileError(p->location, QQmlPropertyCacheCreatorBase::tr("Invalid property type"));
             }
 
-            Q_ASSERT(qmltype.isValid());
-            if (qmltype.isComposite()) {
-                QQmlMetaType::CompositeMetaTypeIds typeIds;
-                if (selfReference) {
-                     typeIds = objectContainer->typeIds();
+            // inline components are not necessarily valid yet
+            Q_ASSERT(qmltype.isValid() || qmltype.isInlineComponentType());
+            if (qmltype.isComposite() || qmltype.isInlineComponentType()) {
+                CompositeMetaTypeIds typeIds;
+                if (qmltype.isInlineComponentType()) {
+                    auto objectId = qmltype.inlineComponendId();
+                    auto containingType = qmltype.containingType();
+                    if (containingType.isValid()) {
+                        auto icType = containingType.lookupInlineComponentById(objectId);
+                        typeIds = {icType.typeId(), icType.qListTypeId()};
+                    } else {
+                        typeIds = {};
+                    }
+                    if (!typeIds.isValid()) // type has not been registered yet, we must be in containing type
+                        typeIds = objectContainer->typeIdsForComponent(objectId);
+                    Q_ASSERT(typeIds.isValid());
+                } else if (selfReference) {
+                     typeIds = objectContainer->typeIdsForComponent();
                 } else {
                     QQmlRefPointer<QQmlTypeData> tdata = enginePrivate->typeLoader.getType(qmltype.sourceUrl());
                     Q_ASSERT(tdata);
                     Q_ASSERT(tdata->isComplete());
 
                     auto compilationUnit = tdata->compilationUnit();
-                    typeIds = compilationUnit->typeIds();
+                    typeIds = compilationUnit->typeIdsForComponent();
                 }
 
                 if (p->isList) {
@@ -539,7 +609,7 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::crea
         }
 
         if (!p->isReadOnly && !p->isList)
-            propertyFlags.isWritable = true;
+            propertyFlags.setIsWritable(true);
 
 
         QString propertyName = stringAt(p->nameIndex);
@@ -578,7 +648,7 @@ inline int QQmlPropertyCacheCreator<ObjectContainer>::metaTypeForParameter(const
         return qmltype.typeId();
 
     if (selfReference)
-        return objectContainer->typeIds().id;
+        return objectContainer->typeIdsForComponent().id;
 
     QQmlRefPointer<QQmlTypeData> tdata = enginePrivate->typeLoader.getType(qmltype.sourceUrl());
     Q_ASSERT(tdata);
@@ -721,7 +791,7 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheAliasCreator<ObjectContainer>:
     bool writable = false;
     bool resettable = false;
 
-    propertyFlags->isAlias = true;
+    propertyFlags->setIsAlias(true);
 
     if (alias.aliasToLocalAlias) {
         const QV4::CompiledData::Alias *lastAlias = &alias;
@@ -806,12 +876,12 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheAliasCreator<ObjectContainer>:
             if (valueTypeIndex != -1) {
                 const QMetaObject *valueTypeMetaObject = QQmlValueTypeFactory::metaObjectForMetaType(*type);
                 if (valueTypeMetaObject->property(valueTypeIndex).isEnumType())
-                    *type = QVariant::Int;
+                    *type = QMetaType::Int;
                 else
                     *type = valueTypeMetaObject->property(valueTypeIndex).userType();
             } else {
                 if (targetProperty->isEnum()) {
-                    *type = QVariant::Int;
+                    *type = QMetaType::Int;
                 } else {
                     // Copy type flags
                     propertyFlags->copyPropertyTypeFlags(targetProperty->flags());
@@ -823,8 +893,8 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheAliasCreator<ObjectContainer>:
         }
     }
 
-    propertyFlags->isWritable = !(alias.flags & QV4::CompiledData::Alias::IsReadOnly) && writable;
-    propertyFlags->isResettable = resettable;
+    propertyFlags->setIsWritable(!(alias.flags & QV4::CompiledData::Alias::IsReadOnly) && writable);
+    propertyFlags->setIsResettable(resettable);
     return QQmlJS::DiagnosticMessage();
 }
 
diff --git a/src/qml/qml/qqmlpropertydata_p.h b/src/qml/qml/qqmlpropertydata_p.h
index dec696226e..2d9091edcd 100644
--- a/src/qml/qml/qqmlpropertydata_p.h
+++ b/src/qml/qml/qqmlpropertydata_p.h
@@ -52,6 +52,7 @@
 //
 
 #include <private/qobject_p.h>
+#include <QtCore/qglobal.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -69,6 +70,7 @@ public:
     typedef QObjectPrivate::StaticMetaCallFunction StaticMetaCallFunction;
 
     struct Flags {
+        friend class QQmlPropertyData;
         enum Types {
             OtherType            = 0,
             FunctionType         = 1, // Is an invokable
@@ -87,30 +89,34 @@ public:
         // trySetStaticMetaCallFunction for details.
         // (Note: this padding is done here, because certain compilers have surprising behavior
         // when an enum is declared in-between two bit fields.)
-        enum { BitsLeftInFlags = 10 };
+        enum { BitsLeftInFlags = 15 };
         unsigned otherBits       : BitsLeftInFlags; // align to 32 bits
 
-        // Can apply to all properties, except IsFunction
-        unsigned isConstant       : 1; // Has CONST flag
-        unsigned isWritable       : 1; // Has WRITE function
-        unsigned isResettable     : 1; // Has RESET function
-        unsigned isAlias          : 1; // Is a QML alias to another property
-        unsigned isFinal          : 1; // Has FINAL flag
-        unsigned isOverridden     : 1; // Is overridden by a extension property
-        unsigned isDirect         : 1; // Exists on a C++ QMetaObject
-
+        // Members of the form aORb can only be a when type is not FunctionType, and only be
+        // b when type equals FunctionType. For that reason, the semantic meaning of the bit is
+        // overloaded, and the accessor functions are used to get the correct value
+        //
+        // Moreover, isSignalHandler, isOverload and isCloned and isConstructor make only sense
+        // for functions, too (and could at a later point be reused for flags that only make sense
+        // for non-functions)
+        //
+        // Lastly, isDirect and isOverridden apply to both functions and non-functions
+    private:
+        unsigned isConstantORisVMEFunction     : 1; // Has CONST flag OR Function was added by QML
+        unsigned isWritableORhasArguments      : 1; // Has WRITE function OR Function takes arguments
+        unsigned isResettableORisSignal        : 1; // Has RESET function OR Function is a signal
+        unsigned isAliasORisVMESignal          : 1; // Is a QML alias to another property OR Signal was added by QML
+        unsigned isFinalORisV4Function         : 1; // Has FINAL flag OR Function takes QQmlV4Function* args
+        unsigned isSignalHandler               : 1; // Function is a signal handler
+        unsigned isOverload                    : 1; // Function is an overload of another function
+        unsigned isCloned                      : 1; // The function was marked as cloned
+        unsigned isConstructor                 : 1; // The function was marked is a constructor
+        unsigned isDirect                      : 1; // Exists on a C++ QMetaObject
+        unsigned isOverridden                  : 1; // Is overridden by a extension property
+    public:
         unsigned type             : 4; // stores an entry of Types
 
         // Apply only to IsFunctions
-        unsigned isVMEFunction    : 1; // Function was added by QML
-        unsigned hasArguments     : 1; // Function takes arguments
-        unsigned isSignal         : 1; // Function is a signal
-        unsigned isVMESignal      : 1; // Signal was added by QML
-        unsigned isV4Function     : 1; // Function takes QQmlV4Function* args
-        unsigned isSignalHandler  : 1; // Function is a signal handler
-        unsigned isOverload       : 1; // Function is an overload of another function
-        unsigned isCloned         : 1; // The function was marked as cloned
-        unsigned isConstructor    : 1; // The function was marked is a constructor
 
         // Internal QQmlPropertyCache flags
         unsigned notFullyResolved : 1; // True if the type data is to be lazily resolved
@@ -119,8 +125,85 @@ public:
         inline Flags();
         inline bool operator==(const Flags &other) const;
         inline void copyPropertyTypeFlags(Flags from);
+
+        void setIsConstant(bool b) {
+            Q_ASSERT(type != FunctionType);
+            isConstantORisVMEFunction = b;
+        }
+
+        void setIsWritable(bool b) {
+            Q_ASSERT(type != FunctionType);
+            isWritableORhasArguments = b;
+        }
+
+        void setIsResettable(bool b) {
+            Q_ASSERT(type != FunctionType);
+            isResettableORisSignal = b;
+        }
+
+        void setIsAlias(bool b) {
+            Q_ASSERT(type != FunctionType);
+            isAliasORisVMESignal = b;
+        }
+
+        void setIsFinal(bool b) {
+            Q_ASSERT(type != FunctionType);
+            isFinalORisV4Function = b;
+        }
+
+        void setIsOverridden(bool b) {
+            isOverridden = b;
+        }
+
+        void setIsDirect(bool b) {
+            isDirect = b;
+        }
+
+        void setIsVMEFunction(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isConstantORisVMEFunction = b;
+        }
+        void setHasArguments(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isWritableORhasArguments = b;
+        }
+        void setIsSignal(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isResettableORisSignal = b;
+        }
+        void setIsVMESignal(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isAliasORisVMESignal = b;
+        }
+
+        void setIsV4Function(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isFinalORisV4Function = b;
+        }
+
+        void setIsSignalHandler(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isSignalHandler = b;
+        }
+
+        void setIsOverload(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isOverload = b;
+        }
+
+        void setIsCloned(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isCloned = b;
+        }
+
+        void setIsConstructor(bool b) {
+            Q_ASSERT(type == FunctionType);
+            isConstructor = b;
+        }
+
     };
 
+
     inline bool operator==(const QQmlPropertyData &) const;
 
     Flags flags() const { return m_flags; }
@@ -133,14 +216,14 @@ public:
 
     bool isValid() const { return coreIndex() != -1; }
 
-    bool isConstant() const { return m_flags.isConstant; }
-    bool isWritable() const { return m_flags.isWritable; }
-    void setWritable(bool onoff) { m_flags.isWritable = onoff; }
-    bool isResettable() const { return m_flags.isResettable; }
-    bool isAlias() const { return m_flags.isAlias; }
-    bool isFinal() const { return m_flags.isFinal; }
+    bool isConstant() const { return !isFunction() && m_flags.isConstantORisVMEFunction; }
+    bool isWritable() const { return !isFunction() && m_flags.isWritableORhasArguments; }
+    void setWritable(bool onoff) { Q_ASSERT(!isFunction()); m_flags.isWritableORhasArguments = onoff; }
+    bool isResettable() const { return !isFunction() && m_flags.isResettableORisSignal; }
+    bool isAlias() const { return !isFunction() && m_flags.isAliasORisVMESignal; }
+    bool isFinal() const { return !isFunction() && m_flags.isFinalORisV4Function; }
     bool isOverridden() const { return m_flags.isOverridden; }
-    bool isDirect() const { return m_flags.isDirect; }
+    bool isDirect() const { return m_flags.isOverload; }
     bool hasStaticMetaCallFunction() const { return staticMetaCallFunction() != nullptr; }
     bool isFunction() const { return m_flags.type == Flags::FunctionType; }
     bool isQObject() const { return m_flags.type == Flags::QObjectDerivedType; }
@@ -150,15 +233,15 @@ public:
     bool isQJSValue() const { return m_flags.type == Flags::QJSValueType; }
     bool isVarProperty() const { return m_flags.type == Flags::VarPropertyType; }
     bool isQVariant() const { return m_flags.type == Flags::QVariantType; }
-    bool isVMEFunction() const { return m_flags.isVMEFunction; }
-    bool hasArguments() const { return m_flags.hasArguments; }
-    bool isSignal() const { return m_flags.isSignal; }
-    bool isVMESignal() const { return m_flags.isVMESignal; }
-    bool isV4Function() const { return m_flags.isV4Function; }
+    bool isVMEFunction() const { return isFunction() && m_flags.isConstantORisVMEFunction; }
+    bool hasArguments() const { return isFunction() && m_flags.isWritableORhasArguments; }
+    bool isSignal() const { return isFunction() && m_flags.isResettableORisSignal; }
+    bool isVMESignal() const { return isFunction() && m_flags.isAliasORisVMESignal; }
+    bool isV4Function() const { return isFunction() && m_flags.isFinalORisV4Function; }
     bool isSignalHandler() const { return m_flags.isSignalHandler; }
     bool isOverload() const { return m_flags.isOverload; }
     void setOverload(bool onoff) { m_flags.isOverload = onoff; }
-    bool isCloned() const { return m_flags.isCloned; }
+    bool isCloned() const { return isFunction() && m_flags.isCloned; }
     bool isConstructor() const { return m_flags.isConstructor; }
 
     bool hasOverride() const { return overrideIndex() >= 0; }
@@ -294,9 +377,9 @@ public:
     static Flags defaultSignalFlags()
     {
         Flags f;
-        f.isSignal = true;
         f.type = Flags::FunctionType;
-        f.isVMESignal = true;
+        f.setIsSignal(true);
+        f.setIsVMESignal(true);
         return f;
     }
 
@@ -304,7 +387,7 @@ public:
     {
         Flags f;
         f.type = Flags::FunctionType;
-        f.isVMEFunction = true;
+        f.setIsVMEFunction(true);
         return f;
     }
 
@@ -348,44 +431,32 @@ bool QQmlPropertyData::operator==(const QQmlPropertyData &other) const
 
 QQmlPropertyData::Flags::Flags()
     : otherBits(0)
-    , isConstant(false)
-    , isWritable(false)
-    , isResettable(false)
-    , isAlias(false)
-    , isFinal(false)
-    , isOverridden(false)
-    , isDirect(false)
-    , type(OtherType)
-    , isVMEFunction(false)
-    , hasArguments(false)
-    , isSignal(false)
-    , isVMESignal(false)
-    , isV4Function(false)
+    , isConstantORisVMEFunction(false)
+    , isWritableORhasArguments(false)
+    , isResettableORisSignal(false)
+    , isAliasORisVMESignal(false)
+    , isFinalORisV4Function(false)
     , isSignalHandler(false)
     , isOverload(false)
     , isCloned(false)
     , isConstructor(false)
+    , isOverridden(false)
+    , type(OtherType)
     , notFullyResolved(false)
     , overrideIndexIsProperty(false)
 {}
 
 bool QQmlPropertyData::Flags::operator==(const QQmlPropertyData::Flags &other) const
 {
-    return isConstant == other.isConstant &&
-            isWritable == other.isWritable &&
-            isResettable == other.isResettable &&
-            isAlias == other.isAlias &&
-            isFinal == other.isFinal &&
+    return isConstantORisVMEFunction == other.isConstantORisVMEFunction &&
+            isWritableORhasArguments == other.isWritableORhasArguments &&
+            isResettableORisSignal == other.isResettableORisSignal &&
+            isAliasORisVMESignal == other.isAliasORisVMESignal &&
+            isFinalORisV4Function == other.isFinalORisV4Function &&
             isOverridden == other.isOverridden &&
-            type == other.type &&
-            isVMEFunction == other.isVMEFunction &&
-            hasArguments == other.hasArguments &&
-            isSignal == other.isSignal &&
-            isVMESignal == other.isVMESignal &&
-            isV4Function == other.isV4Function &&
             isSignalHandler == other.isSignalHandler &&
-            isOverload == other.isOverload &&
             isCloned == other.isCloned &&
+            type == other.type &&
             isConstructor == other.isConstructor &&
             notFullyResolved == other.notFullyResolved &&
             overrideIndexIsProperty == other.overrideIndexIsProperty;
diff --git a/src/qml/qml/qqmlpropertyvalidator.cpp b/src/qml/qml/qqmlpropertyvalidator.cpp
index 238a535b89..8762dc328d 100644
--- a/src/qml/qml/qqmlpropertyvalidator.cpp
+++ b/src/qml/qml/qqmlpropertyvalidator.cpp
@@ -100,6 +100,9 @@ QVector<QQmlJS::DiagnosticMessage> QQmlPropertyValidator::validateObject(
         int objectIndex, const QV4::CompiledData::Binding *instantiatingBinding, bool populatingValueTypeGroupProperty) const
 {
     const QV4::CompiledData::Object *obj = compilationUnit->objectAt(objectIndex);
+    for (auto it = obj->inlineComponentsBegin(); it != obj->inlineComponentsEnd(); ++it) {
+        validateObject(it->objectIndex, /* instantiatingBinding*/ nullptr);
+    }
 
     if (obj->flags & QV4::CompiledData::Object::IsComponent) {
         Q_ASSERT(obj->nBindings == 1);
@@ -398,31 +401,31 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
     switch (property->propType()) {
     case QMetaType::QVariant:
     break;
-    case QVariant::String: {
+    case QMetaType::QString: {
         if (!binding->evaluatesToString()) {
             return warnOrError(tr("Invalid property assignment: string expected"));
         }
     }
     break;
-    case QVariant::StringList: {
+    case QMetaType::QStringList: {
         if (!binding->evaluatesToString()) {
             return warnOrError(tr("Invalid property assignment: string or string list expected"));
         }
     }
     break;
-    case QVariant::ByteArray: {
+    case QMetaType::QByteArray: {
         if (binding->type != QV4::CompiledData::Binding::Type_String) {
             return warnOrError(tr("Invalid property assignment: byte array expected"));
         }
     }
     break;
-    case QVariant::Url: {
+    case QMetaType::QUrl: {
         if (binding->type != QV4::CompiledData::Binding::Type_String) {
             return warnOrError(tr("Invalid property assignment: url expected"));
         }
     }
     break;
-    case QVariant::UInt: {
+    case QMetaType::UInt: {
         if (binding->type == QV4::CompiledData::Binding::Type_Number) {
             double d = compilationUnit->bindingValueAsNumber(binding);
             if (double(uint(d)) == d)
@@ -431,7 +434,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         return warnOrError(tr("Invalid property assignment: unsigned int expected"));
     }
     break;
-    case QVariant::Int: {
+    case QMetaType::Int: {
         if (binding->type == QV4::CompiledData::Binding::Type_Number) {
             double d = compilationUnit->bindingValueAsNumber(binding);
             if (double(int(d)) == d)
@@ -446,13 +449,13 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Double: {
+    case QMetaType::Double: {
         if (binding->type != QV4::CompiledData::Binding::Type_Number) {
             return warnOrError(tr("Invalid property assignment: number expected"));
         }
     }
     break;
-    case QVariant::Color: {
+    case QMetaType::QColor: {
         bool ok = false;
         QQmlStringConverters::rgbaFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -461,7 +464,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
     }
     break;
 #if QT_CONFIG(datestring)
-    case QVariant::Date: {
+    case QMetaType::QDate: {
         bool ok = false;
         QQmlStringConverters::dateFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -469,7 +472,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Time: {
+    case QMetaType::QTime: {
         bool ok = false;
         QQmlStringConverters::timeFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -477,7 +480,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::DateTime: {
+    case QMetaType::QDateTime: {
         bool ok = false;
         QQmlStringConverters::dateTimeFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -486,7 +489,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
     }
     break;
 #endif // datestring
-    case QVariant::Point: {
+    case QMetaType::QPoint: {
         bool ok = false;
         QQmlStringConverters::pointFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -494,7 +497,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::PointF: {
+    case QMetaType::QPointF: {
         bool ok = false;
         QQmlStringConverters::pointFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -502,7 +505,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Size: {
+    case QMetaType::QSize: {
         bool ok = false;
         QQmlStringConverters::sizeFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -510,7 +513,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::SizeF: {
+    case QMetaType::QSizeF: {
         bool ok = false;
         QQmlStringConverters::sizeFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -518,7 +521,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Rect: {
+    case QMetaType::QRect: {
         bool ok = false;
         QQmlStringConverters::rectFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -526,7 +529,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::RectF: {
+    case QMetaType::QRectF: {
         bool ok = false;
         QQmlStringConverters::rectFFromString(compilationUnit->bindingValueAsString(binding), &ok);
         if (!ok) {
@@ -534,13 +537,13 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Bool: {
+    case QMetaType::Bool: {
         if (binding->type != QV4::CompiledData::Binding::Type_Boolean) {
             return warnOrError(tr("Invalid property assignment: boolean expected"));
         }
     }
     break;
-    case QVariant::Vector2D: {
+    case QMetaType::QVector2D: {
         struct {
             float xp;
             float yp;
@@ -550,7 +553,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Vector3D: {
+    case QMetaType::QVector3D: {
         struct {
             float xp;
             float yp;
@@ -561,7 +564,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Vector4D: {
+    case QMetaType::QVector4D: {
         struct {
             float xp;
             float yp;
@@ -573,7 +576,7 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::Quaternion: {
+    case QMetaType::QQuaternion: {
         struct {
             float wp;
             float xp;
@@ -585,8 +588,8 @@ QQmlJS::DiagnosticMessage QQmlPropertyValidator::validateLiteralBinding(QQmlProp
         }
     }
     break;
-    case QVariant::RegExp:
-    case QVariant::RegularExpression:
+    case QMetaType::QRegExp:
+    case QMetaType::QRegularExpression:
         return warnOrError(tr("Invalid property assignment: regular expression expected; use /pattern/ syntax"));
     default: {
         // generate single literal value assignment to a list property if required
diff --git a/src/qml/qml/qqmltype.cpp b/src/qml/qml/qqmltype.cpp
index 4a211ffa53..28fefca239 100644
--- a/src/qml/qml/qqmltype.cpp
+++ b/src/qml/qml/qqmltype.cpp
@@ -84,6 +84,9 @@ QQmlTypePrivate::QQmlTypePrivate(QQmlType::RegistrationType type)
     case QQmlType::CompositeType:
         extraData.fd = new QQmlCompositeTypeData;
         break;
+    case QQmlType::InlineComponentType:
+        extraData.id = new QQmlInlineTypeData;
+        break;
     default: qFatal("QQmlTypePrivate Internal Error.");
     }
 }
@@ -106,6 +109,9 @@ QQmlTypePrivate::~QQmlTypePrivate()
     case QQmlType::CompositeType:
         delete extraData.fd;
         break;
+    case QQmlType::InlineComponentType:
+        delete  extraData.id;
+        break;
     default: //Also InterfaceType, because it has no extra data
         break;
     }
@@ -426,6 +432,12 @@ void QQmlTypePrivate::insertEnumsFromPropertyCache(const QQmlPropertyCache *cach
     insertEnums(cppMetaObject);
 }
 
+void QQmlTypePrivate::setContainingType(QQmlType *containingType)
+{
+    Q_ASSERT(regType == QQmlType::InlineComponentType);
+    extraData.id->containingType = containingType->d.data();
+}
+
 void QQmlTypePrivate::setName(const QString &uri, const QString &element)
 {
     module = uri;
@@ -440,6 +452,8 @@ QByteArray QQmlType::typeName() const
             return d->extraData.sd->singletonInstanceInfo->typeName.toUtf8();
         else if (d->baseMetaObject)
             return d->baseMetaObject->className();
+        else if (d->regType == InlineComponentType)
+            return d->extraData.id->inlineComponentName.toUtf8();
     }
     return QByteArray();
 }
@@ -561,7 +575,11 @@ bool QQmlType::isComposite() const
 
 bool QQmlType::isCompositeSingleton() const
 {
-    return d && d->regType == CompositeSingletonType;
+    // if the outer type is a composite singleton, d->regType will indicate that even for
+    // the inline component type
+    // however, inline components can -at least for now- never be singletons
+    // so we just do one additional check
+    return d && d->regType == CompositeSingletonType && !isInlineComponentType();
 }
 
 bool QQmlType::isQObjectSingleton() const
@@ -677,9 +695,28 @@ int QQmlType::index() const
     return d ? d->index : -1;
 }
 
+bool QQmlType::isInlineComponentType() const {
+    return d ? d->regType == QQmlType::InlineComponentType : false;
+}
+
+int QQmlType::inlineComponendId() const {
+    bool ok = false;
+    if (d->regType == QQmlType::RegistrationType::InlineComponentType) {
+        Q_ASSERT(d->extraData.id->objectId != -1);
+        return d->extraData.id->objectId;
+    }
+    int subObjectId = sourceUrl().fragment().toInt(&ok);
+    return ok ? subObjectId : -1;
+}
+
 QUrl QQmlType::sourceUrl() const
 {
-    return d ? d->sourceUrl() : QUrl();
+    auto url = d ? d->sourceUrl() : QUrl();
+    if (url.isValid() && d->regType == QQmlType::RegistrationType::InlineComponentType && d->extraData.id->objectId) {
+        Q_ASSERT(url.hasFragment());
+        url.setFragment(QString::number(inlineComponendId()));
+    }
+    return url;
 }
 
 int QQmlType::enumValue(QQmlEnginePrivate *engine, const QHashedStringRef &name, bool *ok) const
@@ -845,6 +882,19 @@ int QQmlType::scopedEnumValue(QQmlEnginePrivate *engine, const QStringRef &scope
     return -1;
 }
 
+int QQmlType::inlineComponentObjectId()
+{
+    if (!isInlineComponentType())
+        return -1;
+    return d->extraData.id->objectId;
+}
+
+void QQmlType::setInlineComponentObjectId(int id) const
+{
+    Q_ASSERT(d && d->regType == QQmlType::InlineComponentType);
+    d->extraData.id->objectId = id;
+}
+
 void QQmlType::refHandle(const QQmlTypePrivate *priv)
 {
     if (priv)
@@ -864,4 +914,63 @@ int QQmlType::refCount(const QQmlTypePrivate *priv)
     return -1;
 }
 
+int QQmlType::lookupInlineComponentIdByName(const QString &name) const
+{
+    Q_ASSERT(d);
+    return d->namesToInlineComponentObjectIndex.value(name, -1);
+}
+
+QQmlType QQmlType::containingType() const
+{
+    Q_ASSERT(d && d->regType == QQmlType::RegistrationType::InlineComponentType);
+    auto ret = QQmlType {d->extraData.id->containingType};
+    Q_ASSERT(!ret.isInlineComponentType());
+    return ret;
+}
+
+QQmlType QQmlType::lookupInlineComponentById(int objectid) const
+{
+    Q_ASSERT(d);
+    return d->objectIdToICType.value(objectid, QQmlType(nullptr));
+}
+
+int QQmlType::generatePlaceHolderICId() const
+{
+    Q_ASSERT(d);
+    int id = -2;
+    for (auto it = d->objectIdToICType.keyBegin(); it != d->objectIdToICType.keyEnd(); ++it)
+        if (*it < id)
+                id = *it;
+    return id;
+}
+
+void QQmlType::associateInlineComponent(const QString &name, int objectID, const CompositeMetaTypeIds &metaTypeIds, QQmlType existingType)
+{
+    auto priv = existingType.isValid() ? const_cast<QQmlTypePrivate *>(existingType.d.data()) : new QQmlTypePrivate { RegistrationType::InlineComponentType } ;
+    priv->setName( QString::fromUtf8(typeName()), name);
+    auto icUrl = QUrl(sourceUrl());
+    icUrl.setFragment(QString::number(objectID));
+    priv->extraData.id->url = icUrl;
+    priv->extraData.id->containingType = d.data();
+    priv->extraData.id->objectId = objectID;
+    priv->typeId = metaTypeIds.id;
+    priv->listId = metaTypeIds.listId;
+    d->namesToInlineComponentObjectIndex.insert(name, objectID);
+    QQmlType icType(priv);
+    d->objectIdToICType.insert(objectID, icType);
+}
+
+void QQmlType::setPendingResolutionName(const QString &name)
+{
+    Q_ASSERT(d && d->regType == QQmlType::RegistrationType::InlineComponentType);
+    Q_ASSERT(d->extraData.id->inlineComponentName == name|| d->extraData.id->inlineComponentName.isEmpty());
+    d->extraData.id->inlineComponentName = name;
+}
+
+QString QQmlType::pendingResolutionName() const
+{
+    Q_ASSERT(d && d->regType == QQmlType::RegistrationType::InlineComponentType);
+    return d->extraData.id->inlineComponentName;
+}
+
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmltype_p.h b/src/qml/qml/qqmltype_p.h
index af134b21f1..387baa74bb 100644
--- a/src/qml/qml/qqmltype_p.h
+++ b/src/qml/qml/qqmltype_p.h
@@ -74,6 +74,7 @@ class QQmlPropertyCache;
 namespace QV4 {
 struct String;
 }
+struct CompositeMetaTypeIds;
 
 class Q_QML_PRIVATE_EXPORT QQmlType
 {
@@ -144,6 +145,9 @@ public:
 
     int index() const;
 
+    bool isInlineComponentType() const;
+    int inlineComponendId() const;
+
     struct Q_QML_PRIVATE_EXPORT SingletonInstanceInfo
     {
         QJSValue (*scriptCallback)(QQmlEngine *, QJSEngine *) = nullptr;
@@ -166,6 +170,8 @@ public:
     int scopedEnumValue(QQmlEnginePrivate *engine, int index, const QString &, bool *ok) const;
     int scopedEnumValue(QQmlEnginePrivate *engine, const QByteArray &, const QByteArray &, bool *ok) const;
     int scopedEnumValue(QQmlEnginePrivate *engine, const QStringRef &, const QStringRef &, bool *ok) const;
+    int inlineComponentObjectId();
+    void setInlineComponentObjectId(int id) const; // TODO: const setters are BAD
 
     const QQmlTypePrivate *priv() const { return d.data(); }
     static void refHandle(const QQmlTypePrivate *priv);
@@ -178,9 +184,19 @@ public:
         InterfaceType = 2,
         CompositeType = 3,
         CompositeSingletonType = 4,
+        InlineComponentType = 5,
         AnyRegistrationType = 255
     };
 
+    QQmlType containingType() const;
+    int lookupInlineComponentIdByName(const QString &name) const;
+    QQmlType lookupInlineComponentById(int objectid) const;
+    int generatePlaceHolderICId() const;
+
+    void associateInlineComponent(const QString &name, int objectID, const CompositeMetaTypeIds &metaTypeIds, QQmlType existingType);
+    void setPendingResolutionName(const QString &name);
+    QString pendingResolutionName() const;
+
 private:
     friend class QQmlTypePrivate;
     friend uint qHash(const QQmlType &t, uint seed);
diff --git a/src/qml/qml/qqmltype_p_p.h b/src/qml/qml/qqmltype_p_p.h
index 51f776178c..43344827db 100644
--- a/src/qml/qml/qqmltype_p_p.h
+++ b/src/qml/qml/qqmltype_p_p.h
@@ -56,6 +56,7 @@
 #include <private/qqmlproxymetaobject_p.h>
 #include <private/qqmlrefcount_p.h>
 #include <private/qqmlpropertycache_p.h>
+#include <private/qqmlmetatype_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -69,6 +70,7 @@ public:
     void initEnums(QQmlEnginePrivate *engine) const;
     void insertEnums(const QMetaObject *metaObject) const;
     void insertEnumsFromPropertyCache(const QQmlPropertyCache *cache) const;
+    void setContainingType(QQmlType *containingType);
 
     QUrl sourceUrl() const
     {
@@ -77,6 +79,8 @@ public:
             return extraData.fd->url;
         case QQmlType::CompositeSingletonType:
             return extraData.sd->singletonInstanceInfo->url;
+        case QQmlType::InlineComponentType:
+            return extraData.id->url;
         default:
             return QUrl();
         }
@@ -130,10 +134,23 @@ public:
         QUrl url;
     };
 
+    struct QQmlInlineTypeData
+    {
+        QUrl url = QUrl();
+        // The containing type stores a pointer to the inline component type
+        // Using QQmlType here would create a reference cycle
+        // As the inline component type cannot outlive the containing type
+        // this should still be fine
+        QQmlTypePrivate const * containingType = nullptr;
+        QString inlineComponentName = QString();
+        int objectId = -1;
+    };
+
     union extraData {
         QQmlCppTypeData* cd;
         QQmlSingletonTypeData* sd;
         QQmlCompositeTypeData* fd;
+        QQmlInlineTypeData* id;
     } extraData;
 
     const char *iid;
@@ -160,6 +177,8 @@ public:
     mutable QList<QStringHash<int>*> scopedEnums;
 
     void setName(const QString &uri, const QString &element);
+    mutable QHash<QString, int> namesToInlineComponentObjectIndex;
+    mutable QHash<int, QQmlType> objectIdToICType;
 
 private:
     ~QQmlTypePrivate() override;
diff --git a/src/qml/qml/qqmltypecompiler.cpp b/src/qml/qml/qqmltypecompiler.cpp
index b4d56c9e49..842ca697e0 100644
--- a/src/qml/qml/qqmltypecompiler.cpp
+++ b/src/qml/qml/qqmltypecompiler.cpp
@@ -58,10 +58,10 @@ QQmlTypeCompiler::QQmlTypeCompiler(QQmlEnginePrivate *engine, QQmlTypeData *type
                                    QV4::ResolvedTypeReferenceMap *resolvedTypeCache, const QV4::CompiledData::DependentTypesHasher &dependencyHasher)
     : resolvedTypes(resolvedTypeCache)
     , engine(engine)
-    , typeData(typeData)
     , dependencyHasher(dependencyHasher)
-    , typeNameCache(typeNameCache)
     , document(parsedQML)
+    , typeNameCache(typeNameCache)
+    , typeData(typeData)
 {
 }
 
@@ -279,9 +279,9 @@ void QQmlTypeCompiler::addImport(const QString &module, const QString &qualifier
     document->imports.append(import);
 }
 
-QQmlMetaType::CompositeMetaTypeIds QQmlTypeCompiler::typeIds() const
+CompositeMetaTypeIds QQmlTypeCompiler::typeIdsForComponent(int objectId) const
 {
-    return typeData->typeIds();
+    return typeData->typeIds(objectId);
 }
 
 QQmlCompilePass::QQmlCompilePass(QQmlTypeCompiler *typeCompiler)
@@ -1215,7 +1215,7 @@ bool QQmlDeferredAndCustomParserBindingScanner::scanObject(int objectIndex)
     if (obj->idNameIndex != 0)
         _seenObjectWithId = true;
 
-    if (obj->flags & QV4::CompiledData::Object::IsComponent) {
+    if (obj->flags & QV4::CompiledData::Object::IsComponent && !obj->isInlineComponent) {
         Q_ASSERT(obj->bindingCount() == 1);
         const QV4::CompiledData::Binding *componentBinding = obj->firstBinding();
         Q_ASSERT(componentBinding->type == QV4::CompiledData::Binding::Type_Object);
diff --git a/src/qml/qml/qqmltypecompiler_p.h b/src/qml/qml/qqmltypecompiler_p.h
index b43089dc06..319df8673b 100644
--- a/src/qml/qml/qqmltypecompiler_p.h
+++ b/src/qml/qml/qqmltypecompiler_p.h
@@ -79,7 +79,9 @@ struct QQmlTypeCompiler
 {
     Q_DECLARE_TR_FUNCTIONS(QQmlTypeCompiler)
 public:
-    QQmlTypeCompiler(QQmlEnginePrivate *engine, QQmlTypeData *typeData, QmlIR::Document *document,
+    QQmlTypeCompiler(QQmlEnginePrivate *engine,
+                     QQmlTypeData *typeData,
+                     QmlIR::Document *document,
                      const QQmlRefPointer<QQmlTypeNameCache> &typeNameCache,
                      QV4::ResolvedTypeReferenceMap *resolvedTypeCache,
                      const QV4::CompiledData::DependentTypesHasher &dependencyHasher);
@@ -129,14 +131,12 @@ public:
         return resolvedTypes->value(id);
     }
 
-    QQmlMetaType::CompositeMetaTypeIds typeIds() const;
+    CompositeMetaTypeIds typeIdsForComponent(int objectId = 0) const;
 
 private:
     QList<QQmlError> errors;
     QQmlEnginePrivate *engine;
-    QQmlTypeData *typeData;
     const QV4::CompiledData::DependentTypesHasher &dependencyHasher;
-    QQmlRefPointer<QQmlTypeNameCache> typeNameCache;
     QmlIR::Document *document;
     // index is string index of type name (use obj->inheritedTypeNameIndex)
     QHash<int, QQmlCustomParser*> customParsers;
@@ -144,6 +144,9 @@ private:
     // index in first hash is component index, vector inside contains object indices of objects with id property
     QVector<quint32> m_componentRoots;
     QQmlPropertyCacheVector m_propertyCaches;
+
+    QQmlRefPointer<QQmlTypeNameCache> typeNameCache;
+    QQmlTypeData *typeData;
 };
 
 struct QQmlCompilePass
diff --git a/src/qml/qml/qqmltypedata.cpp b/src/qml/qml/qqmltypedata.cpp
index 22587c226a..f7abe67921 100644
--- a/src/qml/qml/qqmltypedata.cpp
+++ b/src/qml/qml/qqmltypedata.cpp
@@ -92,6 +92,25 @@ QV4::ExecutableCompilationUnit *QQmlTypeData::compilationUnit() const
     return m_compiledData.data();
 }
 
+QV4::ExecutableCompilationUnit *QQmlTypeData::compilationUnitForInlineComponent(unsigned int icObjectId) const
+{
+    Q_ASSERT(m_document || m_compiledData);
+    if (m_compiledData)
+        return m_compiledData.data();
+    for (auto it = m_document->objects.begin(); it != m_document->objects.end(); ++it) {
+        auto object = *it;
+        auto icIt = std::find_if(object->inlineComponentsBegin(), object->inlineComponentsEnd(), [&](const QV4::CompiledData::InlineComponent &ic) {
+            return ic.objectIndex == icObjectId;
+        });
+        if (icIt != object->inlineComponentsEnd()) {
+            Q_ASSERT(m_inlineComponentToCompiledData.contains(icIt->nameIndex));
+            return m_inlineComponentToCompiledData[icIt->nameIndex].data();
+        }
+    }
+    Q_UNREACHABLE();
+    return nullptr; // make integrity happy
+}
+
 void QQmlTypeData::registerCallback(TypeDataCallback *callback)
 {
     Q_ASSERT(!m_callbacks.contains(callback));
@@ -105,8 +124,10 @@ void QQmlTypeData::unregisterCallback(TypeDataCallback *callback)
     Q_ASSERT(!m_callbacks.contains(callback));
 }
 
-QQmlMetaType::CompositeMetaTypeIds QQmlTypeData::typeIds() const
+CompositeMetaTypeIds QQmlTypeData::typeIds(int objectId) const
 {
+    if (objectId != 0)
+        return m_inlineComponentData[objectId].typeIds;
     return m_typeIds;
 }
 
@@ -135,8 +156,15 @@ bool QQmlTypeData::tryLoadFromDiskCache()
 
     m_compiledData = unit;
 
-    for (int i = 0, count = m_compiledData->objectCount(); i < count; ++i)
-        m_typeReferences.collectFromObject(m_compiledData->objectAt(i));
+    QVector<QV4::CompiledData::InlineComponent> ics;
+    for (int i = 0, count = m_compiledData->objectCount(); i < count; ++i) {
+        auto object = m_compiledData->objectAt(i);
+        m_typeReferences.collectFromObject(object);
+        const auto inlineComponentTable = object->inlineComponentTable();
+        for (auto i = 0; i != object->nInlineComponents; ++i) {
+            ics.push_back(inlineComponentTable[i]);
+        }
+    }
 
     m_importCache.setBaseUrl(finalUrl(), finalUrlString());
 
@@ -183,6 +211,20 @@ bool QQmlTypeData::tryLoadFromDiskCache()
         }
     }
 
+    QQmlType containingType;
+    auto containingTypeName = finalUrl().fileName().split(QLatin1Char('.')).first();
+    int major = -1, minor = -1;
+    QQmlImportNamespace *ns = nullptr;
+    m_importCache.resolveType(containingTypeName, &containingType, &major, &minor, &ns);
+    for (auto&& ic: ics) {
+        QString const nameString = m_compiledData->stringAt(ic.nameIndex);
+        QByteArray const name = nameString.toUtf8();
+        auto importUrl = finalUrl();
+        importUrl.setFragment(QString::number(ic.objectIndex));
+        auto import = new QQmlImportInstance();
+        m_importCache.addInlineComponentImport(import, nameString, importUrl, containingType);
+    }
+
     return true;
 }
 
@@ -233,6 +275,36 @@ static bool addTypeReferenceChecksumsToHash(const QList<QQmlTypeData::TypeRefere
     return true;
 }
 
+// local helper function for inline components
+namespace  {
+template<typename ObjectContainer>
+void setupICs(const ObjectContainer &container, QHash<int, InlineComponentData> *icData, const QUrl &finalUrl) {
+    Q_ASSERT(icData->empty());
+    for (int i = 0; i != container->objectCount(); ++i) {
+        auto root = container->objectAt(i);
+        for (auto it = root->inlineComponentsBegin(); it != root->inlineComponentsEnd(); ++it) {
+            auto url = finalUrl;
+            url.setFragment(QString::number(it->objectIndex));
+            const QByteArray &className = QQmlPropertyCacheCreatorBase::createClassNameTypeByUrl(url);
+            InlineComponentData icDatum(QQmlMetaType::registerInternalCompositeType(className), int(it->objectIndex), int(it->nameIndex), 0, 0, 0);
+            icData->insert(it->objectIndex, icDatum);
+        }
+    }
+};
+}
+
+template<typename Container>
+void QQmlTypeData::setCompileUnit(const Container &container)
+{
+    for (int i = 0; i != container->objectCount(); ++i) {
+        auto const root = container->objectAt(i);
+        for (auto it = root->inlineComponentsBegin(); it != root->inlineComponentsEnd(); ++it) {
+            auto *typeRef = m_compiledData->resolvedType(it->nameIndex);
+            typeRef->compilationUnit = m_compiledData; // share compilation unit
+        }
+    }
+}
+
 void QQmlTypeData::done()
 {
     auto cleanup = qScopeGuard([this]{
@@ -263,10 +335,30 @@ void QQmlTypeData::done()
     }
 
     // Check all type dependencies for errors
-    for (auto it = m_resolvedTypes.constBegin(), end = m_resolvedTypes.constEnd(); it != end;
+    for (auto it = qAsConst(m_resolvedTypes).begin(), end = qAsConst(m_resolvedTypes).end(); it != end;
          ++it) {
         const TypeReference &type = *it;
-        Q_ASSERT(!type.typeData || type.typeData->isCompleteOrError());
+        Q_ASSERT(!type.typeData || type.typeData->isCompleteOrError() || type.type.isInlineComponentType());
+        if (type.type.isInlineComponentType() && !type.type.pendingResolutionName().isEmpty()) {
+            auto containingType = type.type.containingType();
+            auto objectId = containingType.lookupInlineComponentIdByName(type.type.pendingResolutionName());
+            if (objectId < 0) { // can be any negative number if we tentatively resolved it in QQmlImport but it actually was not an inline component
+                const QString typeName = stringAt(it.key());
+                int lastDot = typeName.lastIndexOf('.');
+
+                QList<QQmlError> errors = type.typeData ? type.typeData->errors() : QList<QQmlError>{};
+                QQmlError error;
+                error.setUrl(url());
+                error.setLine(type.location.line);
+                error.setColumn(type.location.column);
+                error.setDescription(QQmlTypeLoader::tr("Type %1 has no inline component type called %2").arg(typeName.leftRef(lastDot), type.type.pendingResolutionName()));
+                errors.prepend(error);
+                setError(errors);
+                return;
+            } else {
+                type.type.setInlineComponentObjectId(objectId);
+            }
+        }
         if (type.typeData && type.typeData->isError()) {
             const QString typeName = stringAt(it.key());
 
@@ -304,13 +396,23 @@ void QQmlTypeData::done()
     m_typeClassName = QQmlPropertyCacheCreatorBase::createClassNameTypeByUrl(finalUrl());
     if (!m_typeClassName.isEmpty())
         m_typeIds = QQmlMetaType::registerInternalCompositeType(m_typeClassName);
+
+    if (m_document) {
+        setupICs(m_document, &m_inlineComponentData, finalUrl());
+    } else {
+        setupICs(m_compiledData, &m_inlineComponentData, finalUrl());
+    }
     auto typeCleanupGuard = qScopeGuard([&]() {
-        if (isError() && m_typeIds.isValid())
+        if (isError() && m_typeIds.isValid()) {
             QQmlMetaType::unregisterInternalCompositeType(m_typeIds);
+            for (auto&& icData: qAsConst(m_inlineComponentData)) {
+                QQmlMetaType::unregisterInternalCompositeType(icData.typeIds);
+            }
+        }
     });
 
-    QQmlRefPointer<QQmlTypeNameCache> typeNameCache;
     QV4::ResolvedTypeReferenceMap resolvedTypeCache;
+    QQmlRefPointer<QQmlTypeNameCache> typeNameCache;
     {
         QQmlJS::DiagnosticMessage error = buildTypeResolutionCaches(&typeNameCache, &resolvedTypeCache);
         if (error.isValid()) {
@@ -342,8 +444,12 @@ void QQmlTypeData::done()
     if (!m_document.isNull()) {
         // Compile component
         compile(typeNameCache, &resolvedTypeCache, dependencyHasher);
+        if (!isError())
+            setCompileUnit(m_document);
     } else {
         createTypeAndPropertyCaches(typeNameCache, resolvedTypeCache);
+        if (!isError())
+            setCompileUnit(m_compiledData);
     }
 
     if (isError())
@@ -351,6 +457,7 @@ void QQmlTypeData::done()
 
     {
         QQmlEnginePrivate *const enginePrivate = QQmlEnginePrivate::get(engine);
+        m_compiledData->inlineComponentData = m_inlineComponentData;
         {
             // Sanity check property bindings
             QQmlPropertyValidator validator(enginePrivate, m_importCache, m_compiledData);
@@ -389,6 +496,26 @@ void QQmlTypeData::done()
         }
     }
 
+    // associate inline components to root component
+    {
+        auto typeName = finalUrlString().splitRef('/').last().split('.').first().toString();
+        // typeName can be empty if a QQmlComponent was constructed with an empty QUrl parameter
+        if (!typeName.isEmpty() && typeName.at(0).isUpper() && !m_inlineComponentData.isEmpty()) {
+            QHashedStringRef const hashedStringRef { typeName };
+            QList<QQmlError> errors;
+            auto type = QQmlMetaType::typeForUrl(finalUrlString(), hashedStringRef, false, &errors);
+            Q_ASSERT(errors.empty());
+            if (type.isValid()) {
+                for (auto const &icDatum : m_inlineComponentData) {
+                    Q_ASSERT(icDatum.typeIds.isValid());
+                    QQmlType existingType = type.lookupInlineComponentById(type.lookupInlineComponentIdByName(m_compiledData->stringAt(icDatum.nameIndex)));
+                    type.associateInlineComponent(m_compiledData->stringAt(icDatum.nameIndex),
+                                                  icDatum.objectIndex, icDatum.typeIds, existingType);
+                }
+            }
+        }
+    }
+
     {
         // Collect imported scripts
         m_compiledData->dependentScripts.reserve(m_scripts.count());
@@ -522,6 +649,22 @@ void QQmlTypeData::restoreIR(QV4::CompiledData::CompilationUnit &&unit)
 
 void QQmlTypeData::continueLoadFromIR()
 {
+    QQmlType containingType;
+    auto containingTypeName = finalUrl().fileName().split(QLatin1Char('.')).first();
+    int major = -1, minor = -1;
+    QQmlImportNamespace *ns = nullptr;
+    m_importCache.resolveType(containingTypeName, &containingType, &major, &minor, &ns);
+    for (auto const& object: m_document->objects) {
+        for (auto it = object->inlineComponentsBegin(); it != object->inlineComponentsEnd(); ++it) {
+            QString const nameString = m_document->stringAt(it->nameIndex);
+            QByteArray const name = nameString.toUtf8();
+            auto importUrl = finalUrl();
+            importUrl.setFragment(QString::number(it->objectIndex));
+            auto import = new QQmlImportInstance(); // Note: The cache takes ownership of the QQmlImportInstance
+            m_importCache.addInlineComponentImport(import, nameString, importUrl, containingType);
+        }
+    }
+
     m_typeReferences.collectFromObjects(m_document->objects.constBegin(), m_document->objects.constEnd());
     m_importCache.setBaseUrl(finalUrl(), finalUrlString());
 
@@ -724,6 +867,17 @@ void QQmlTypeData::resolveTypes()
             ref.typeData = typeLoader()->getType(ref.type.sourceUrl());
             addDependency(ref.typeData.data());
         }
+        if (ref.type.isInlineComponentType()) {
+            auto containingType = ref.type.containingType();
+            if (containingType.isValid()) {
+                auto const url = containingType.sourceUrl();
+                if (url.isValid()) {
+                    auto typeData = typeLoader()->getType(url);
+                    ref.typeData = typeData;
+                    addDependency(typeData.data());
+                }
+            }
+        }
         ref.majorVersion = majorVersion;
         ref.minorVersion = minorVersion;
 
@@ -731,7 +885,6 @@ void QQmlTypeData::resolveTypes()
         ref.location.column = unresolvedRef->location.column;
 
         ref.needsCreation = unresolvedRef->needsCreation;
-
         m_resolvedTypes.insert(unresolvedRef.key(), ref);
     }
 
@@ -766,6 +919,38 @@ QQmlJS::DiagnosticMessage QQmlTypeData::buildTypeResolutionCaches(
                 return qQmlCompileError(resolvedType->location, tr("Composite Singleton Type %1 is not creatable.").arg(qmlType.qmlTypeName()));
             }
             ref->compilationUnit = resolvedType->typeData->compilationUnit();
+            if (resolvedType->type.isInlineComponentType()) {
+                // Inline component which is part of an already resolved type
+                int objectId = -1;
+                if (qmlType.containingType().isValid()) {
+                    objectId = qmlType.containingType().lookupInlineComponentIdByName(QString::fromUtf8(qmlType.typeName()));
+                    qmlType.setInlineComponentObjectId(objectId);
+                } else  {
+                    objectId = resolvedType->type.inlineComponendId();
+                }
+                Q_ASSERT(objectId != -1);
+                ref->typePropertyCache = resolvedType->typeData->compilationUnit()->propertyCaches.at(objectId);
+                ref->type = qmlType;
+                Q_ASSERT(ref->type.isInlineComponentType());
+            }
+        } else if (resolvedType->type.isInlineComponentType()) {
+            // Inline component, defined in the file we are currently compiling
+            if (!m_inlineComponentToCompiledData.contains(resolvedType.key())) {
+                ref->type = qmlType;
+                if (qmlType.isValid()) {
+                    // this is required for inline components in singletons
+                    auto typeID = qmlType.lookupInlineComponentById(qmlType.inlineComponendId()).typeId();
+                    auto exUnit = engine->obtainExecutableCompilationUnit(typeID);
+                    if (exUnit) {
+                        ref->compilationUnit = exUnit;
+                        ref->typePropertyCache = engine->propertyCacheForType(typeID);
+                    }
+                }
+            } else {
+                ref->compilationUnit = m_inlineComponentToCompiledData[resolvedType.key()];
+                ref->typePropertyCache = m_inlineComponentToCompiledData[resolvedType.key()]->rootPropertyCache();
+            }
+
         } else if (qmlType.isValid() && !resolvedType->selfReference) {
             ref->type = qmlType;
             Q_ASSERT(ref->type.isValid());
diff --git a/src/qml/qml/qqmltypedata_p.h b/src/qml/qml/qqmltypedata_p.h
index 53e78e06d7..d894090b36 100644
--- a/src/qml/qml/qqmltypedata_p.h
+++ b/src/qml/qml/qqmltypedata_p.h
@@ -86,6 +86,8 @@ private:
     friend class QQmlTypeLoader;
 
     QQmlTypeData(const QUrl &, QQmlTypeLoader *);
+    template<typename Container>
+    void setCompileUnit(const Container &container);
 
 public:
     ~QQmlTypeData() override;
@@ -93,6 +95,7 @@ public:
     const QList<ScriptReference> &resolvedScripts() const;
 
     QV4::ExecutableCompilationUnit *compilationUnit() const;
+    QV4::ExecutableCompilationUnit *compilationUnitForInlineComponent(unsigned int icObjectId) const;
 
     // Used by QQmlComponent to get notifications
     struct TypeDataCallback {
@@ -103,7 +106,7 @@ public:
     void registerCallback(TypeDataCallback *);
     void unregisterCallback(TypeDataCallback *);
 
-    QQmlMetaType::CompositeMetaTypeIds typeIds() const;
+    CompositeMetaTypeIds typeIds(int objectId = 0) const;
     QByteArray typeClassName() const { return m_typeClassName; }
 
 protected:
@@ -155,10 +158,15 @@ private:
     bool m_typesResolved:1;
 
     // Used for self-referencing types, otherwise -1.
-    QQmlMetaType::CompositeMetaTypeIds m_typeIds;
+    CompositeMetaTypeIds m_typeIds;
     QByteArray m_typeClassName; // used for meta-object later
 
-    QQmlRefPointer<QV4::ExecutableCompilationUnit> m_compiledData;
+    using ExecutableCompilationUnitPtr = QQmlRefPointer<QV4::ExecutableCompilationUnit>;
+
+    QHash<int, InlineComponentData> m_inlineComponentData;
+
+    ExecutableCompilationUnitPtr m_compiledData;
+    QHash<int, ExecutableCompilationUnitPtr> m_inlineComponentToCompiledData;
 
     QList<TypeDataCallback *> m_callbacks;
 
diff --git a/src/qml/qml/qqmltypeloader.cpp b/src/qml/qml/qqmltypeloader.cpp
index 2de158884b..e9a38945fa 100644
--- a/src/qml/qml/qqmltypeloader.cpp
+++ b/src/qml/qml/qqmltypeloader.cpp
@@ -357,8 +357,8 @@ void QQmlTypeLoader::networkReplyFinished(QNetworkReply *reply)
         }
     }
 
-    if (reply->error()) {
-        blob->networkError(reply->error());
+    if (reply->networkError()) {
+        blob->networkError(reply->networkError());
     } else {
         QByteArray data = reply->readAll();
         setData(blob, data);
diff --git a/src/qml/qml/qqmlvaluetype.cpp b/src/qml/qml/qqmlvaluetype.cpp
index d83fc4bb48..4beb6a4d07 100644
--- a/src/qml/qml/qqmlvaluetype.cpp
+++ b/src/qml/qml/qqmlvaluetype.cpp
@@ -48,6 +48,8 @@
 #endif
 #include <private/qmetatype_p.h>
 
+Q_DECLARE_METATYPE(QQmlProperty)
+
 QT_BEGIN_NAMESPACE
 
 namespace {
@@ -62,7 +64,7 @@ struct QQmlValueTypeFactoryImpl
     const QMetaObject *metaObjectForMetaType(int);
     QQmlValueType *valueType(int);
 
-    QQmlValueType *valueTypes[QVariant::UserType];
+    QQmlValueType *valueTypes[QMetaType::User];
     QHash<int, QQmlValueType *> userTypes;
     QMutex mutex;
 
@@ -71,7 +73,7 @@ struct QQmlValueTypeFactoryImpl
 
 QQmlValueTypeFactoryImpl::QQmlValueTypeFactoryImpl()
 {
-    std::fill_n(valueTypes, int(QVariant::UserType), &invalidValueType);
+    std::fill_n(valueTypes, int(QMetaType::User), &invalidValueType);
 
 #if QT_CONFIG(qml_itemmodel)
     // See types wrapped in qqmlmodelindexvaluetype_p.h
@@ -118,26 +120,26 @@ bool QQmlValueTypeFactoryImpl::isValueType(int idx)
 const QMetaObject *QQmlValueTypeFactoryImpl::metaObjectForMetaType(int t)
 {
     switch (t) {
-    case QVariant::Point:
+    case QMetaType::QPoint:
         return &QQmlPointValueType::staticMetaObject;
-    case QVariant::PointF:
+    case QMetaType::QPointF:
         return &QQmlPointFValueType::staticMetaObject;
-    case QVariant::Size:
+    case QMetaType::QSize:
         return &QQmlSizeValueType::staticMetaObject;
-    case QVariant::SizeF:
+    case QMetaType::QSizeF:
         return &QQmlSizeFValueType::staticMetaObject;
-    case QVariant::Rect:
+    case QMetaType::QRect:
         return &QQmlRectValueType::staticMetaObject;
-    case QVariant::RectF:
+    case QMetaType::QRectF:
         return &QQmlRectFValueType::staticMetaObject;
 #if QT_CONFIG(easingcurve)
-    case QVariant::EasingCurve:
+    case QMetaType::QEasingCurve:
         return &QQmlEasingValueType::staticMetaObject;
 #endif
 #if QT_CONFIG(qml_itemmodel)
-    case QVariant::ModelIndex:
+    case QMetaType::QModelIndex:
         return &QQmlModelIndexValueType::staticMetaObject;
-    case QVariant::PersistentModelIndex:
+    case QMetaType::QPersistentModelIndex:
         return &QQmlPersistentModelIndexValueType::staticMetaObject;
 #endif
     default:
@@ -145,7 +147,8 @@ const QMetaObject *QQmlValueTypeFactoryImpl::metaObjectForMetaType(int t)
         if (t == qMetaTypeId<QItemSelectionRange>())
             return &QQmlItemSelectionRangeValueType::staticMetaObject;
 #endif
-
+        if (t == qMetaTypeId<QQmlProperty>())
+            return &QQmlPropertyValueType::staticMetaObject;
         if (const QMetaObject *mo = QQml_valueTypeProvider()->metaObjectForMetaType(t))
             return mo;
         break;
@@ -159,7 +162,7 @@ const QMetaObject *QQmlValueTypeFactoryImpl::metaObjectForMetaType(int t)
 
 QQmlValueType *QQmlValueTypeFactoryImpl::valueType(int idx)
 {
-    if (idx >= (int)QVariant::UserType) {
+    if (idx >= (int)QMetaType::User) {
         // Protect the hash with a mutex
         mutex.lock();
 
@@ -585,6 +588,16 @@ void QQmlEasingValueType::setBezierCurve(const QVariantList &customCurveVariant)
     v = newEasingCurve;
 }
 
+QObject *QQmlPropertyValueType::object() const
+{
+    return v.object();
+}
+
+QString QQmlPropertyValueType::name() const
+{
+    return v.name();
+}
+
 QVariantList QQmlEasingValueType::bezierCurve() const
 {
     QVariantList rv;
diff --git a/src/qml/qml/qqmlvaluetype_p.h b/src/qml/qml/qqmlvaluetype_p.h
index 0601237c4b..ff664adbe7 100644
--- a/src/qml/qml/qqmlvaluetype_p.h
+++ b/src/qml/qml/qqmlvaluetype_p.h
@@ -268,6 +268,17 @@ public:
 };
 #endif
 
+struct QQmlPropertyValueType
+{
+    QQmlProperty v;
+    Q_PROPERTY(QObject *object READ object CONSTANT FINAL)
+    Q_PROPERTY(QString name READ name CONSTANT FINAL)
+    Q_GADGET
+public:
+    QObject *object() const;
+    QString name() const;
+};
+
 template<typename T>
 int qmlRegisterValueTypeEnums(const char *uri, int versionMajor, int versionMinor, const char *qmlName)
 {
diff --git a/src/qml/qml/qqmlvaluetypewrapper.cpp b/src/qml/qml/qqmlvaluetypewrapper.cpp
index f23921497c..ba5ba96cbe 100644
--- a/src/qml/qml/qqmlvaluetypewrapper.cpp
+++ b/src/qml/qml/qqmlvaluetypewrapper.cpp
@@ -601,7 +601,7 @@ bool QQmlValueTypeWrapper::virtualPut(Managed *m, PropertyKey id, const Value &v
 
     QVariant v = v4->toVariant(value, property.userType());
 
-    if (property.isEnumType() && (QMetaType::Type)v.type() == QMetaType::Double)
+    if (property.isEnumType() && (QMetaType::Type)v.userType() == QMetaType::Double)
         v = v.toInt();
 
     void *gadget = r->d()->gadgetPtr();
diff --git a/src/qml/qml/qqmlvmemetaobject.cpp b/src/qml/qml/qqmlvmemetaobject.cpp
index 42a90e234c..ecb86e2f10 100644
--- a/src/qml/qml/qqmlvmemetaobject.cpp
+++ b/src/qml/qml/qqmlvmemetaobject.cpp
@@ -291,7 +291,7 @@ bool QQmlInterceptorMetaObject::intercept(QMetaObject::Call c, int id, void **a)
             const int valueIndex = vi->m_propertyIndex.valueTypeIndex();
             int type = QQmlData::get(object)->propertyCache->property(id)->propType();
 
-            if (type != QVariant::Invalid) {
+            if (type != QMetaType::UnknownType) {
                 if (valueIndex != -1) {
                     QQmlValueType *valueType = QQmlValueTypeFactory::valueType(type);
                     Q_ASSERT(valueType);
@@ -534,7 +534,7 @@ QUrl QQmlVMEMetaObject::readPropertyAsUrl(int id) const
     QV4::Scope scope(engine);
     QV4::ScopedValue sv(scope, *(md->data() + id));
     const QV4::VariantObject *v = sv->as<QV4::VariantObject>();
-    if (!v || v->d()->data().type() != QVariant::Url)
+    if (!v || v->d()->data().userType() != QMetaType::QUrl)
         return QUrl();
     return v->d()->data().value<QUrl>();
 }
@@ -548,7 +548,7 @@ QDate QQmlVMEMetaObject::readPropertyAsDate(int id) const
     QV4::Scope scope(engine);
     QV4::ScopedValue sv(scope, *(md->data() + id));
     const QV4::VariantObject *v = sv->as<QV4::VariantObject>();
-    if (!v || v->d()->data().type() != QVariant::Date)
+    if (!v || v->d()->data().userType() != QMetaType::QDate)
         return QDate();
     return v->d()->data().value<QDate>();
 }
@@ -562,7 +562,7 @@ QDateTime QQmlVMEMetaObject::readPropertyAsDateTime(int id)
     QV4::Scope scope(engine);
     QV4::ScopedValue sv(scope, *(md->data() + id));
     const QV4::VariantObject *v = sv->as<QV4::VariantObject>();
-    if (!v || v->d()->data().type() != QVariant::DateTime)
+    if (!v || v->d()->data().userType() != QMetaType::QDateTime)
         return QDateTime();
     return v->d()->data().value<QDateTime>();
 }
@@ -576,7 +576,7 @@ QSizeF QQmlVMEMetaObject::readPropertyAsSizeF(int id) const
     QV4::Scope scope(engine);
     QV4::ScopedValue sv(scope, *(md->data() + id));
     const QV4::VariantObject *v = sv->as<QV4::VariantObject>();
-    if (!v || v->d()->data().type() != QVariant::SizeF)
+    if (!v || v->d()->data().userType() != QMetaType::QSizeF)
         return QSizeF();
     return v->d()->data().value<QSizeF>();
 }
@@ -590,7 +590,7 @@ QPointF QQmlVMEMetaObject::readPropertyAsPointF(int id) const
     QV4::Scope scope(engine);
     QV4::ScopedValue sv(scope, *(md->data() + id));
     const QV4::VariantObject *v = sv->as<QV4::VariantObject>();
-    if (!v || v->d()->data().type() != QVariant::PointF)
+    if (!v || v->d()->data().userType() != QMetaType::QPointF)
         return QPointF();
     return v->d()->data().value<QPointF>();
 }
@@ -634,7 +634,7 @@ QRectF QQmlVMEMetaObject::readPropertyAsRectF(int id) const
     QV4::Scope scope(engine);
     QV4::ScopedValue sv(scope, *(md->data() + id));
     const QV4::VariantObject *v = sv->as<QV4::VariantObject>();
-    if (!v || v->d()->data().type() != QVariant::RectF)
+    if (!v || v->d()->data().userType() != QMetaType::QRectF)
         return QRectF();
     return v->d()->data().value<QRectF>();
 }
diff --git a/src/qml/qml/qqmlxmlhttprequest.cpp b/src/qml/qml/qqmlxmlhttprequest.cpp
index 2afbdb616b..c820499703 100644
--- a/src/qml/qml/qqmlxmlhttprequest.cpp
+++ b/src/qml/qml/qqmlxmlhttprequest.cpp
@@ -1291,7 +1291,7 @@ void QQmlXMLHttpRequest::requestFromUrl(const QUrl &url)
         if (m_network->bytesAvailable() > 0)
             readyRead();
 
-        QNetworkReply::NetworkError networkError = m_network->error();
+        QNetworkReply::NetworkError networkError = m_network->networkError();
         if (networkError != QNetworkReply::NoError) {
             error(networkError);
         } else {
diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
index 2c1956553f..02032142ee 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
@@ -340,22 +340,22 @@ ReturnedValue QtObject::method_colorEqual(const FunctionObject *b, const Value *
     bool ok = false;
 
     QVariant lhs = scope.engine->toVariant(argv[0], -1);
-    if (lhs.userType() == QVariant::String) {
+    if (lhs.userType() == QMetaType::QString) {
         lhs = QQmlStringConverters::colorFromString(lhs.toString(), &ok);
         if (!ok) {
             THROW_GENERIC_ERROR("Qt.colorEqual(): Invalid color name");
         }
-    } else if (lhs.userType() != QVariant::Color) {
+    } else if (lhs.userType() != QMetaType::QColor) {
         THROW_GENERIC_ERROR("Qt.colorEqual(): Invalid arguments");
     }
 
     QVariant rhs = scope.engine->toVariant(argv[1], -1);
-    if (rhs.userType() == QVariant::String) {
+    if (rhs.userType() == QMetaType::QString) {
         rhs = QQmlStringConverters::colorFromString(rhs.toString(), &ok);
         if (!ok) {
             THROW_GENERIC_ERROR("Qt.colorEqual(): Invalid color name");
         }
-    } else if (rhs.userType() != QVariant::Color) {
+    } else if (rhs.userType() != QMetaType::QColor) {
         THROW_GENERIC_ERROR("Qt.colorEqual(): Invalid arguments");
     }
 
@@ -606,13 +606,13 @@ ReturnedValue QtObject::method_lighter(const FunctionObject *b, const Value *, c
         THROW_GENERIC_ERROR("Qt.lighter(): Invalid arguments");
 
     QVariant v = scope.engine->toVariant(argv[0], -1);
-    if (v.userType() == QVariant::String) {
+    if (v.userType() == QMetaType::QString) {
         bool ok = false;
         v = QQmlStringConverters::colorFromString(v.toString(), &ok);
         if (!ok) {
             return QV4::Encode::null();
         }
-    } else if (v.userType() != QVariant::Color) {
+    } else if (v.userType() != QMetaType::QColor) {
         return QV4::Encode::null();
     }
 
@@ -646,13 +646,13 @@ ReturnedValue QtObject::method_darker(const FunctionObject *b, const Value *, co
         THROW_GENERIC_ERROR("Qt.darker(): Invalid arguments");
 
     QVariant v = scope.engine->toVariant(argv[0], -1);
-    if (v.userType() == QVariant::String) {
+    if (v.userType() == QMetaType::QString) {
         bool ok = false;
         v = QQmlStringConverters::colorFromString(v.toString(), &ok);
         if (!ok) {
             return QV4::Encode::null();
         }
-    } else if (v.userType() != QVariant::Color) {
+    } else if (v.userType() != QMetaType::QColor) {
         return QV4::Encode::null();
     }
 
@@ -697,25 +697,25 @@ ReturnedValue QtObject::method_tint(const FunctionObject *b, const Value *, cons
 
     // base color
     QVariant v1 = scope.engine->toVariant(argv[0], -1);
-    if (v1.userType() == QVariant::String) {
+    if (v1.userType() == QMetaType::QString) {
         bool ok = false;
         v1 = QQmlStringConverters::colorFromString(v1.toString(), &ok);
         if (!ok) {
             return QV4::Encode::null();
         }
-    } else if (v1.userType() != QVariant::Color) {
+    } else if (v1.userType() != QMetaType::QColor) {
         return QV4::Encode::null();
     }
 
     // tint color
     QVariant v2 = scope.engine->toVariant(argv[1], -1);
-    if (v2.userType() == QVariant::String) {
+    if (v2.userType() == QMetaType::QString) {
         bool ok = false;
         v2 = QQmlStringConverters::colorFromString(v2.toString(), &ok);
         if (!ok) {
             return QV4::Encode::null();
         }
-    } else if (v2.userType() != QVariant::Color) {
+    } else if (v2.userType() != QMetaType::QColor) {
         return QV4::Encode::null();
     }
 
@@ -789,7 +789,7 @@ ReturnedValue QtObject::method_formatTime(const FunctionObject *b, const Value *
 
     QVariant argVariant = scope.engine->toVariant(argv[0], -1);
     QTime time;
-    if (argv[0].as<DateObject>() || (argVariant.type() == QVariant::String))
+    if (argv[0].as<DateObject>() || (argVariant.userType() == QMetaType::QString))
         time = argVariant.toDateTime().time();
     else // if (argVariant.type() == QVariant::Time), or invalid.
         time = argVariant.toTime();
@@ -1332,6 +1332,41 @@ ReturnedValue QtObject::method_createComponent(const FunctionObject *b, const Va
     return QV4::QObjectWrapper::wrap(scope.engine, c);
 }
 
+ReturnedValue QtObject::method_get_uiLanguage(const FunctionObject *b, const Value * /*thisObject*/, const Value * /*argv*/, int /*argc*/)
+{
+    QV4::Scope scope(b);
+    QJSEngine *jsEngine = scope.engine->jsEngine();
+    if (!jsEngine)
+        return Encode::null();
+
+    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(scope.engine);
+    if (ep && ep->propertyCapture) {
+        static int propertyIndex = -1;
+        static int notifySignalIndex = -1;
+        if (propertyIndex < 0) {
+            QMetaProperty metaProperty =
+                    QQmlEngine::staticMetaObject.property(QQmlEngine::staticMetaObject.indexOfProperty("uiLanguage"));
+            propertyIndex = metaProperty.propertyIndex();
+            notifySignalIndex = metaProperty.notifySignalIndex();
+        }
+        ep->propertyCapture->captureProperty(QQmlEnginePrivate::get(ep), propertyIndex, notifySignalIndex);
+    }
+
+    return Encode(scope.engine->newString(QJSEnginePrivate::get(jsEngine)->uiLanguage));
+}
+
+ReturnedValue QtObject::method_set_uiLanguage(const FunctionObject *b, const Value * /*thisObject*/, const Value *argv, int argc)
+{
+    Scope scope(b);
+    if (!argc)
+        THROW_TYPE_ERROR();
+    QJSEngine *jsEngine = scope.engine->jsEngine();
+    if (!jsEngine)
+        THROW_TYPE_ERROR();
+    jsEngine->setUiLanguage(argv[0].toQString());
+    return Encode::undefined();
+}
+
 #if QT_CONFIG(qml_locale)
 /*!
     \qmlmethod Qt::locale(name)
@@ -1829,6 +1864,14 @@ void QV4::GlobalExtensions::init(Object *globalObject, QJSEngine::Extensions ext
         globalObject->defineDefaultProperty(QStringLiteral("qsTrId"), QV4::GlobalExtensions::method_qsTrId);
         globalObject->defineDefaultProperty(QStringLiteral("QT_TRID_NOOP"), QV4::GlobalExtensions::method_qsTrIdNoOp);
 
+        ScopedString qtName(scope, v4->newString(QStringLiteral("Qt")));
+        ScopedObject qt(scope, globalObject->get(qtName));
+        if (!qt) {
+            qt = v4->newObject();
+            globalObject->defineDefaultProperty(qtName, qt);
+        }
+        qt->defineAccessorProperty(QStringLiteral("uiLanguage"), QV4::QtObject::method_get_uiLanguage, QV4::QtObject::method_set_uiLanguage);
+
         // string prototype extension
         scope.engine->stringPrototype()->defineDefaultProperty(QStringLiteral("arg"), QV4::GlobalExtensions::method_string_arg);
     #endif
diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions_p.h b/src/qml/qml/v8/qqmlbuiltinfunctions_p.h
index d87b83ba10..5cbb52471d 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions_p.h
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions_p.h
@@ -126,6 +126,8 @@ struct QtObject : Object
     static ReturnedValue method_resolvedUrl(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc);
     static ReturnedValue method_createQmlObject(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc);
     static ReturnedValue method_createComponent(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc);
+    static ReturnedValue method_get_uiLanguage(const FunctionObject *b, const Value *, const Value *, int);
+    static ReturnedValue method_set_uiLanguage(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc);
 #if QT_CONFIG(qml_locale)
     static ReturnedValue method_locale(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc);
 #endif