5 files changed, 48 insertions, 14 deletions

diff --git a/src/qml/qml/qqmlincubator_p.h b/src/qml/qml/qqmlincubator_p.h
index aadb147bd5..a674ff274f 100644
--- a/src/qml/qml/qqmlincubator_p.h
+++ b/src/qml/qml/qqmlincubator_p.h
@@ -61,9 +61,7 @@
 
 QT_BEGIN_NAMESPACE
 
-class QQmlPropertyData;
-struct RequiredPropertyInfo;
-using RequiredProperties = QHash<QQmlPropertyData*, RequiredPropertyInfo>;
+class RequiredProperties;
 
 class QQmlIncubator;
 class Q_QML_PRIVATE_EXPORT QQmlIncubatorPrivate : public QQmlEnginePrivate::Incubator
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index a26cdba53a..6cc2bf49c8 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -1505,23 +1505,45 @@ bool QQmlObjectCreator::populateInstance(int index, QObject *instance, QObject *
     if (_compiledObject->flags & QV4::CompiledData::Object::HasDeferredBindings)
         _ddata->deferData(_compiledObjectIndex, compilationUnit, context);
 
+    QSet<QString> postHocRequired;
+    for (auto it = _compiledObject->requiredPropertyExtraDataBegin(); it != _compiledObject->requiredPropertyExtraDataEnd(); ++it)
+        postHocRequired.insert(stringAt(it->nameIndex));
+    bool hadInheritedRequiredProperties = !postHocRequired.empty();
+
     for (int propertyIndex = 0; propertyIndex != _compiledObject->propertyCount(); ++propertyIndex) {
         const QV4::CompiledData::Property* property = _compiledObject->propertiesBegin() + propertyIndex;
         QQmlPropertyData *propertyData = _propertyCache->property(_propertyCache->propertyOffset() + propertyIndex);
-        if (property->isRequired) {
-            sharedState->hadRequiredProperties = true;
-            sharedState->requiredProperties.insert(propertyData,
-                                                   RequiredPropertyInfo {compilationUnit->stringAt(property->nameIndex), compilationUnit->finalUrl(), property->location, {}});
-        }
+        // only compute stringAt if there's a chance for the lookup to succeed
+        auto postHocIt = postHocRequired.isEmpty() ? postHocRequired.end() : postHocRequired.find(stringAt(property->nameIndex));
+        if (!property->isRequired && postHocRequired.end() == postHocIt)
+            continue;
+        if (postHocIt != postHocRequired.end())
+            postHocRequired.erase(postHocIt);
+        sharedState->hadRequiredProperties = true;
+        sharedState->requiredProperties.insert(propertyData,
+                                               RequiredPropertyInfo {compilationUnit->stringAt(property->nameIndex), compilationUnit->finalUrl(), property->location, {}});
+
     }
 
     for (int i = 0; i <= _propertyCache->propertyOffset(); ++i) {
-        QQmlPropertyData *propertyData = _propertyCache->property(i);
-        if (propertyData && propertyData->isRequired()) {
-            sharedState->hadRequiredProperties = true;
-            sharedState->requiredProperties.insert(propertyData, RequiredPropertyInfo {propertyData->name(_qobject),  compilationUnit->finalUrl(), _compiledObject->location, {}});
-        }
+        QQmlPropertyData *propertyData = _propertyCache->maybeUnresolvedProperty(i);
+        if (!propertyData)
+            continue;
+        if (!propertyData->isRequired() && postHocRequired.isEmpty())
+            continue;
+        QString name = propertyData->name(_qobject);
+        auto postHocIt = postHocRequired.find(name);
+        if (!propertyData->isRequired() && postHocRequired.end() == postHocIt )
+            continue;
+
+        if (postHocIt != postHocRequired.end())
+            postHocRequired.erase(postHocIt);
+
+        sharedState->hadRequiredProperties = true;
+        sharedState->requiredProperties.insert(propertyData, RequiredPropertyInfo {name,  compilationUnit->finalUrl(), _compiledObject->location, {}});
     }
+    if (!postHocRequired.isEmpty() && hadInheritedRequiredProperties)
+        recordError({}, QLatin1String("Property %1 was marked as required but does not exist").arg(*postHocRequired.begin()));
 
     if (_compiledObject->nFunctions > 0)
         setupFunctions();
diff --git a/src/qml/qml/qqmlobjectcreator_p.h b/src/qml/qml/qqmlobjectcreator_p.h
index f8ad90be15..bca450addb 100644
--- a/src/qml/qml/qqmlobjectcreator_p.h
+++ b/src/qml/qml/qqmlobjectcreator_p.h
@@ -86,7 +86,7 @@ struct RequiredPropertyInfo
     QVector<AliasToRequiredInfo> aliasesToRequired;
 };
 
-using RequiredProperties = QHash<QQmlPropertyData*, RequiredPropertyInfo>;
+class RequiredProperties : public QHash<QQmlPropertyData*, RequiredPropertyInfo> {};
 
 struct QQmlObjectCreatorSharedState : public QSharedData
 {
diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index 8d91fa29e4..540e6afda1 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -400,6 +400,19 @@ const QMetaObject *QQmlPropertyCache::createMetaObject()
     return _metaObject;
 }
 
+QQmlPropertyData *QQmlPropertyCache::maybeUnresolvedProperty(int index) const
+{
+    if (index < 0 || index >= (propertyIndexCacheStart + propertyIndexCache.count()))
+        return nullptr;
+
+    QQmlPropertyData *rv = nullptr;
+    if (index < propertyIndexCacheStart)
+        return _parent->maybeUnresolvedProperty(index);
+    else
+        rv = const_cast<QQmlPropertyData *>(&propertyIndexCache.at(index - propertyIndexCacheStart));
+    return rv;
+}
+
 QQmlPropertyData *QQmlPropertyCache::defaultProperty() const
 {
     return property(defaultPropertyName(), nullptr, nullptr);
diff --git a/src/qml/qml/qqmlpropertycache_p.h b/src/qml/qml/qqmlpropertycache_p.h
index 9c576aab39..9e6eaf9778 100644
--- a/src/qml/qml/qqmlpropertycache_p.h
+++ b/src/qml/qml/qqmlpropertycache_p.h
@@ -120,6 +120,7 @@ public:
     }
 
     QQmlPropertyData *property(int) const;
+    QQmlPropertyData *maybeUnresolvedProperty(int) const;
     QQmlPropertyData *method(int) const;
     QQmlPropertyData *signal(int index) const;
     QQmlEnumData *qmlEnum(int) const;