QmlCompiler: Implement LoadElement for value type lists

Instead of the storedType hack in the type resolver, properly declare
the type LoadElement can return: A merge of undefined and the actual
type. This way we can choose the best concrete type to use for this
independently (and optimize it later).

Task-number: QTBUG-103529
Change-Id: I17b1f835f6a893ec843a90491e92f72ecb2e87fe
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

6 files changed, 40 insertions, 23 deletions

diff --git a/src/qmlcompiler/qqmljscodegenerator.cpp b/src/qmlcompiler/qqmljscodegenerator.cpp
index b04bff000f..8568154e3c 100644
--- a/src/qmlcompiler/qqmljscodegenerator.cpp
+++ b/src/qmlcompiler/qqmljscodegenerator.cpp
@@ -627,11 +627,6 @@ void QQmlJSCodeGenerator::generate_LoadElement(int base)
         return;
     }
 
-    if (!m_typeResolver->registerIsStoredIn(baseType, m_typeResolver->listPropertyType())) {
-        reject(u"indirect LoadElement"_s);
-        return;
-    }
-
     AccumulatorConverter registers(this);
 
     const QString baseName = registerVariable(base);
@@ -646,18 +641,32 @@ void QQmlJSCodeGenerator::generate_LoadElement(int base)
                 + voidAssignment
                 + u"else "_s;
     }
-    // Our QQmlListProperty only keeps plain QObject*.
-    const auto valueType = m_typeResolver->valueType(baseType);
-    const auto elementType = m_typeResolver->globalType(
-                m_typeResolver->genericType(m_typeResolver->containedType(valueType)));
+
+    if (m_typeResolver->registerIsStoredIn(baseType, m_typeResolver->listPropertyType())) {
+        // Our QQmlListProperty only keeps plain QObject*.
+        const auto valueType = m_typeResolver->valueType(baseType);
+        const auto elementType = m_typeResolver->globalType(
+                    m_typeResolver->genericType(m_typeResolver->containedType(valueType)));
+
+        m_body += u"if ("_s + indexName + u" >= 0 && "_s + indexName
+                + u" < "_s + baseName + u".count(&"_s + baseName
+                + u"))\n"_s;
+        m_body += u"    "_s + m_state.accumulatorVariableOut + u" = "_s +
+                conversion(elementType, m_state.accumulatorOut(),
+                           baseName + u".at(&"_s + baseName + u", "_s
+                           + indexName + u')') + u";\n"_s;
+        m_body += u"else\n"_s
+                + voidAssignment;
+        return;
+    }
+
+    const auto elementType = m_typeResolver->valueType(baseType);
 
     m_body += u"if ("_s + indexName + u" >= 0 && "_s + indexName
-            + u" < "_s + baseName + u".count(&"_s + baseName
-            + u"))\n"_s;
+            + u" < "_s + baseName + u".count())\n"_s;
     m_body += u"    "_s + m_state.accumulatorVariableOut + u" = "_s +
             conversion(elementType, m_state.accumulatorOut(),
-                       baseName + u".at(&"_s + baseName + u", "_s
-                       + indexName + u')') + u";\n"_s;
+                       baseName + u".at("_s + indexName + u')') + u";\n"_s;
     m_body += u"else\n"_s
             + voidAssignment;
 }
diff --git a/src/qmlcompiler/qqmljstypepropagator.cpp b/src/qmlcompiler/qqmljstypepropagator.cpp
index 8aaa75aaa6..7f859061fa 100644
--- a/src/qmlcompiler/qqmljstypepropagator.cpp
+++ b/src/qmlcompiler/qqmljstypepropagator.cpp
@@ -667,7 +667,10 @@ void QQmlJSTypePropagator::generate_LoadElement(int base)
         addReadAccumulator(m_typeResolver->globalType(m_typeResolver->realType()));
 
     addReadRegister(base, baseRegister);
-    setAccumulator(m_typeResolver->valueType(baseRegister));
+    // We can end up with undefined.
+    setAccumulator(m_typeResolver->merge(
+            m_typeResolver->valueType(baseRegister),
+            m_typeResolver->globalType(m_typeResolver->voidType())));
 }
 
 void QQmlJSTypePropagator::generate_StoreElement(int base, int index)
diff --git a/src/qmlcompiler/qqmljstyperesolver.cpp b/src/qmlcompiler/qqmljstyperesolver.cpp
index 654eeb7e02..c01cf5dfb3 100644
--- a/src/qmlcompiler/qqmljstyperesolver.cpp
+++ b/src/qmlcompiler/qqmljstyperesolver.cpp
@@ -1205,15 +1205,8 @@ QQmlJSRegisterContent QQmlJSTypeResolver::valueType(const QQmlJSRegisterContent
     property.setTypeName(value->internalName());
     property.setType(value);
 
-    QQmlJSScope::ConstPtr stored;
-
-    // Special handling of stored type here: List lookup can always produce undefined
-    if (isPrimitive(value))
-        stored = jsPrimitiveType();
-    else
-        stored = jsValueType();
-
-    return QQmlJSRegisterContent::create(stored, property, QQmlJSRegisterContent::ListValue, scope);
+    return QQmlJSRegisterContent::create(
+            storedType(value), property, QQmlJSRegisterContent::ListValue, scope);
 }
 
 QQmlJSRegisterContent QQmlJSTypeResolver::returnType(
diff --git a/tests/auto/qml/qmlcppcodegen/data/outOfBounds.qml b/tests/auto/qml/qmlcppcodegen/data/outOfBounds.qml
index 14933a0792..a9f6725a5a 100644
--- a/tests/auto/qml/qmlcppcodegen/data/outOfBounds.qml
+++ b/tests/auto/qml/qmlcppcodegen/data/outOfBounds.qml
@@ -2,5 +2,6 @@ import QtQuick
 
 Item {
     property var oob: children[12]
+    property QtObject oob2: children[123]
     Component.onCompleted: console.log("oob", children[11])
 }
diff --git a/tests/auto/qml/qmlcppcodegen/data/typedArray.qml b/tests/auto/qml/qmlcppcodegen/data/typedArray.qml
index 5ec54572a9..f9a40f5584 100644
--- a/tests/auto/qml/qmlcppcodegen/data/typedArray.qml
+++ b/tests/auto/qml/qmlcppcodegen/data/typedArray.qml
@@ -10,4 +10,8 @@ QtObject {
     property list<date> values4: [aDate, aDate, aDate]
     property list<real> values5: [1, 2, 3.4, "30", undefined, null]
     property list<QtObject> values6: [self, self, self]
+
+    property int inIntList: values3[1]
+    property date inDateList: values4[2]
+    property real inRealList: values5[3]
 }
diff --git a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
index 1ccbd81745..b4993d1752 100644
--- a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
+++ b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
@@ -937,6 +937,9 @@ void tst_QmlCppCodegen::outOfBoundsArray()
     QVERIFY(!object.isNull());
     QVERIFY(object->metaObject()->indexOfProperty("oob") > 0);
     QVERIFY(!object->property("oob").isValid());
+    const QVariant oob2 = object->property("oob2");
+    QCOMPARE(oob2.metaType(), QMetaType::fromType<QObject *>());
+    QCOMPARE(oob2.value<QObject *>(), nullptr);
 }
 
 void tst_QmlCppCodegen::compositeSingleton()
@@ -1948,6 +1951,10 @@ void tst_QmlCppCodegen::typedArray()
     QCOMPARE(values6.count(&values6), 3);
     for (int i = 0; i < 3; ++i)
         QCOMPARE(values6.at(&values6, i), o.data());
+
+    QCOMPARE(o->property("inIntList").toInt(), 2);
+    QCOMPARE(qvariant_cast<QDateTime>(o->property("inDateList")), date);
+    QCOMPARE(o->property("inRealList").toDouble(), 30.0);
 }
 
 void tst_QmlCppCodegen::prefixedType()