QmlCompiler: Fix a number of warts regarding type lookup

There was a condition missing in qqml.cpp making most type lookups crash
right away. Furthermore, we need to generate code for type lookups we do
need.

Fixes: QTBUG-102019
Change-Id: I34e9de7686528b39a35e59c616e4e28b32a6e031
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit 5901fba81195ed725ffd7ad6c278e44f41b6df6f)

9 files changed, 96 insertions, 5 deletions

diff --git a/src/qml/jsruntime/qv4lookup_p.h b/src/qml/jsruntime/qv4lookup_p.h
index d964fadd18..cd7c5e10d9 100644
--- a/src/qml/jsruntime/qv4lookup_p.h
+++ b/src/qml/jsruntime/qv4lookup_p.h
@@ -167,7 +167,7 @@ struct Q_QML_PRIVATE_EXPORT Lookup {
             ReturnedValue (*getterTrampoline)(Lookup *l, ExecutionEngine *engine);
         } qmlContextGlobalLookup;
         struct {
-            Heap::Object *qmlTypeWrapper;
+            Heap::Base *qmlTypeWrapper;
             quintptr unused2;
         } qmlTypeLookup;
         struct {
diff --git a/src/qml/jsruntime/qv4qmlcontext.cpp b/src/qml/jsruntime/qv4qmlcontext.cpp
index f7a5f897c8..edcccdd1b8 100644
--- a/src/qml/jsruntime/qv4qmlcontext.cpp
+++ b/src/qml/jsruntime/qv4qmlcontext.cpp
@@ -268,7 +268,7 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
                 result = QQmlTypeWrapper::create(v4, scopeObject, context->imports(), r.importNamespace);
             }
             if (lookup) {
-                lookup->qmlTypeLookup.qmlTypeWrapper = static_cast<Heap::Object*>(result->heapObject());
+                lookup->qmlTypeLookup.qmlTypeWrapper = result->heapObject();
                 lookup->qmlContextPropertyGetter = QQmlContextWrapper::lookupType;
             }
             return result->asReturnedValue();
@@ -718,7 +718,7 @@ ReturnedValue QQmlContextWrapper::lookupType(Lookup *l, ExecutionEngine *engine,
     if (scopeObject && QQmlData::wasDeleted(scopeObject))
         return QV4::Encode::undefined();
 
-    Heap::Object *heapObject = l->qmlTypeLookup.qmlTypeWrapper;
+    Heap::Base *heapObject = l->qmlTypeLookup.qmlTypeWrapper;
     if (static_cast<Heap::QQmlTypeWrapper *>(heapObject)->object != scopeObject) {
         l->qmlTypeLookup.qmlTypeWrapper = nullptr;
         l->qmlContextPropertyGetter = QQmlContextWrapper::resolveQmlContextPropertyLookupGetter;
diff --git a/src/qml/qml/qqml.cpp b/src/qml/qml/qqml.cpp
index b5ba3d778f..8781e4bf50 100644
--- a/src/qml/qml/qqml.cpp
+++ b/src/qml/qml/qqml.cpp
@@ -1398,6 +1398,8 @@ static void initTypeWrapperLookup(
             l->qmlContextPropertyGetter = qmlContextPropertyGetter;
             if (qmlContextPropertyGetter == QV4::QQmlContextWrapper::lookupSingleton)
                 l->qmlContextSingletonLookup.singletonObject = wrapper->heapObject();
+            else if (qmlContextPropertyGetter == QV4::QQmlContextWrapper::lookupType)
+                l->qmlTypeLookup.qmlTypeWrapper = wrapper->heapObject();
             return;
         }
         scope.engine->throwTypeError();
diff --git a/src/qmlcompiler/qqmljscodegenerator.cpp b/src/qmlcompiler/qqmljscodegenerator.cpp
index addda79063..34bb402f7e 100644
--- a/src/qmlcompiler/qqmljscodegenerator.cpp
+++ b/src/qmlcompiler/qqmljscodegenerator.cpp
@@ -992,6 +992,13 @@ void QQmlJSCodeGenerator::generate_GetLookup(int index)
                 + indexString + u", "_qs + namespaceString + u')';
         generateLookup(lookup, initialization);
         return;
+    } else if (m_state.accumulatorOut.variant() == QQmlJSRegisterContent::MetaType) {
+        const QString lookup = u"aotContext->loadTypeLookup("_qs + indexString
+                + u", &"_qs + m_state.accumulatorVariableOut + u')';
+        const QString initialization = u"aotContext->initLoadTypeLookup("_qs + indexString
+                + u", "_qs + namespaceString + u")"_qs;
+        generateLookup(lookup, initialization);
+        return;
     }
 
     Q_ASSERT(m_state.accumulatorOut.isProperty());
@@ -2528,13 +2535,17 @@ QString QQmlJSCodeGenerator::conversion(const QQmlJSScope::ConstPtr &from,
 
     if (from->accessSemantics() == QQmlJSScope::AccessSemantics::Reference) {
         if (to->accessSemantics() == QQmlJSScope::AccessSemantics::Reference) {
+            // Compare internalName here. The same C++ type can be exposed muliple times in
+            // different QML types. However, the C++ names have to be unique. We can always
+            // static_cast to those.
+
             for (QQmlJSScope::ConstPtr base = from; base; base = base->baseType()) {
                 // We still have to cast as other execution paths may result in different types.
-                if (base == to)
+               if (base->internalName() == to->internalName())
                     return u"static_cast<"_qs + to->internalName() + u" *>("_qs + variable + u')';
             }
             for (QQmlJSScope::ConstPtr base = to; base; base = base->baseType()) {
-                if (base == from)
+               if (base->internalName() == from->internalName())
                     return u"static_cast<"_qs + to->internalName() + u" *>("_qs + variable + u')';
             }
         } else if (to == m_typeResolver->boolType()) {
diff --git a/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt b/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt
index 4d585b62f0..36741105af 100644
--- a/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt
+++ b/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt
@@ -4,6 +4,7 @@ set(cpp_sources
     dynamicmeta.h
     objectwithmethod.h
     person.cpp person.h
+    state.h
     theme.cpp theme.h
     timelinetheme.cpp timelinetheme.h
 )
@@ -30,6 +31,7 @@ set(qml_files
     SelectionRectangle.qml
     Test.qml
     TestCase.qml
+    WindowDerived.qml
     aliasLookup.qml
     anchorsFill.qml
     array.qml
@@ -103,6 +105,7 @@ set(qml_files
     page.qml
     parentProp.qml
     popContextAfterRet.qml
+    prefixedMetaType.qml
     pressAndHoldButton.qml
     registerelimination.qml
     revisions.qml
diff --git a/tests/auto/qml/qmlcppcodegen/data/WindowDerived.qml b/tests/auto/qml/qmlcppcodegen/data/WindowDerived.qml
new file mode 100644
index 0000000000..5e35d425e3
--- /dev/null
+++ b/tests/auto/qml/qmlcppcodegen/data/WindowDerived.qml
@@ -0,0 +1,3 @@
+import TestTypes as Test
+
+Test.WindowInstance {}
diff --git a/tests/auto/qml/qmlcppcodegen/data/prefixedMetaType.qml b/tests/auto/qml/qmlcppcodegen/data/prefixedMetaType.qml
new file mode 100644
index 0000000000..0039d7a4c7
--- /dev/null
+++ b/tests/auto/qml/qmlcppcodegen/data/prefixedMetaType.qml
@@ -0,0 +1,18 @@
+import QtQml
+import TestTypes as Test
+
+QtObject {
+    id: self
+    property int state
+    property QtObject a: Test.WindowInstance {}
+    property QtObject b: a as Test.WindowInstance
+    property QtObject c: self as Test.WindowInstance
+
+    property QtObject d: Test.WindowDerived {}
+    property QtObject e: d as Test.WindowDerived
+    property QtObject f: self as Test.WindowDerived
+
+    Component.onCompleted: {
+        self.state = Test.WindowState.UNCALIBRATED
+    }
+}
diff --git a/tests/auto/qml/qmlcppcodegen/data/state.h b/tests/auto/qml/qmlcppcodegen/data/state.h
new file mode 100644
index 0000000000..287b774c88
--- /dev/null
+++ b/tests/auto/qml/qmlcppcodegen/data/state.h
@@ -0,0 +1,28 @@
+#ifndef STATE_H
+#define STATE_H
+
+#include <QObject>
+#include <QtQml/qqmlregistration.h>
+
+namespace model {
+namespace Window {
+Q_NAMESPACE
+QML_NAMED_ELEMENT(WindowState)
+enum State {
+    OPEN,
+    TILT,
+    UNCALIBRATED,
+    CLOSE
+};
+Q_ENUM_NS(State)
+}
+
+class WindowInstance : public QObject
+{
+    Q_OBJECT
+    QML_ELEMENT
+};
+
+}
+
+#endif // STATE_H
diff --git a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
index acc117d967..bc6fa5a106 100644
--- a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
+++ b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
@@ -125,6 +125,7 @@ private slots:
     void objectInVar();
     void testIsnan();
     void fallbackLookups();
+    void prefixedMetaType();
 };
 
 void tst_QmlCppCodegen::simpleBinding()
@@ -1880,6 +1881,31 @@ void tst_QmlCppCodegen::fallbackLookups()
     QCOMPARE(singleton->objectName(), QStringLiteral("dd96"));
 }
 
+void tst_QmlCppCodegen::prefixedMetaType()
+{
+    QQmlEngine engine;
+
+    // We need to add an import path here because we cannot namespace the implicit import.
+    // The implicit import is what we use for all the other tests, even if we explicitly
+    // import TestTypes. That is because the TestTypes module is in a subdirectory "data".
+    engine.addImportPath(u":/"_qs);
+
+    const QUrl document(u"qrc:/TestTypes/prefixedMetaType.qml"_qs);
+    QQmlComponent c(&engine, document);
+    QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+    QScopedPointer<QObject> o(c.create());
+    QVERIFY(o);
+
+    QCOMPARE(o->property("state").toInt(), 2);
+    QVERIFY(qvariant_cast<QObject *>(o->property("a")) != nullptr);
+    QVERIFY(qvariant_cast<QObject *>(o->property("b")) != nullptr);
+    QVERIFY(qvariant_cast<QObject *>(o->property("c")) == nullptr);
+
+    QVERIFY(qvariant_cast<QObject *>(o->property("d")) != nullptr);
+    QVERIFY(qvariant_cast<QObject *>(o->property("e")) != nullptr);
+    QVERIFY(qvariant_cast<QObject *>(o->property("f")) == nullptr);
+}
+
 void tst_QmlCppCodegen::runInterpreted()
 {
     if (qEnvironmentVariableIsSet("QV4_FORCE_INTERPRETER"))