5 files changed, 64 insertions, 3 deletions
diff --git a/src/qmlcompiler/qqmljscodegenerator.cpp b/src/qmlcompiler/qqmljscodegenerator.cpp
index 9b69a2f3cf..67aa2a5c1f 100644
--- a/src/qmlcompiler/qqmljscodegenerator.cpp
+++ b/src/qmlcompiler/qqmljscodegenerator.cpp
@@ -238,9 +238,19 @@ QT_WARNING_POP
 
             result.code += registerIt->variableName + u" = "_s;
 
-            const QString originalValue
-                    = u"(*static_cast<"_s + castTargetName(originalArgument.storedType())
-                    + u"*>(argv["_s + QString::number(argumentIndex + 1) + u"]))"_s;
+            const auto originalContained = m_typeResolver->originalContainedType(argument);
+            QString originalValue;
+            const bool needsQVariantWrapping = !m_typeResolver->globalType(storedType).isList()
+                    && !originalContained->isReferenceType()
+                    && m_typeResolver->equals(storedType, m_typeResolver->varType())
+                    && !m_typeResolver->equals(originalContained, m_typeResolver->varType());
+            if (needsQVariantWrapping) {
+                originalValue = u"QVariant(%1, argv[%2])"_s.arg(metaTypeFromName(originalContained))
+                                        .arg(QString::number(argumentIndex + 1));
+            } else {
+                originalValue = u"(*static_cast<"_s + castTargetName(originalArgument.storedType())
+                        + u"*>(argv["_s + QString::number(argumentIndex + 1) + u"]))"_s;
+            }
 
             if (needsConversion)
                 result.code += conversion(originalArgument, argument, originalValue);
diff --git a/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt b/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt
index 889edbe0a6..4a113fb964 100644
--- a/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt
+++ b/tests/auto/qml/qmlcppcodegen/data/CMakeLists.txt
@@ -14,6 +14,7 @@ set(cpp_sources
     getOptionalLookup.h
     gadgetwithenum.h
     invisible.h
+    largeValueType.h
     listprovider.h
     multiforeign.h
     objectwithmethod.h
@@ -73,6 +74,7 @@ set(qml_files
     StoreMetaEnum.qml
     Test.qml
     TestCase.qml
+    ValueTypeArgument.qml
     Variable.qml
     WindowDerived.qml
     aliasLookup.qml
diff --git a/tests/auto/qml/qmlcppcodegen/data/ValueTypeArgument.qml b/tests/auto/qml/qmlcppcodegen/data/ValueTypeArgument.qml
new file mode 100644
index 0000000000..5da1b253e0
--- /dev/null
+++ b/tests/auto/qml/qmlcppcodegen/data/ValueTypeArgument.qml
@@ -0,0 +1,21 @@
+pragma Strict
+
+import QtQml
+import TestTypes
+
+QtObject {
+    id: root
+    property largeValueType l
+
+    function callee(l: largeValueType) : void {
+        console.log("Reading l.i=" + l.i)
+    }
+
+    function caller() : void {
+        callee(root.l)
+    }
+
+    Component.onCompleted: {
+        caller()
+    }
+}
diff --git a/tests/auto/qml/qmlcppcodegen/data/largeValueType.h b/tests/auto/qml/qmlcppcodegen/data/largeValueType.h
new file mode 100644
index 0000000000..028a5f690f
--- /dev/null
+++ b/tests/auto/qml/qmlcppcodegen/data/largeValueType.h
@@ -0,0 +1,15 @@
+#include <qqmlintegration.h>
+#include <qqml.h>
+
+class LargeValueType
+{
+    Q_GADGET
+    QML_VALUE_TYPE(largeValueType)
+    Q_PROPERTY(int i READ i)
+
+private:
+    int i() const { return m_i; }
+
+    char m_probablyDefinitelyBiggerThanQVariantInlineStorage[2048]{};
+    int m_i = 5;
+};
diff --git a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
index 5505e30e3b..e5e30e0210 100644
--- a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
+++ b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
@@ -248,6 +248,7 @@ private slots:
     void unstoredUndefined();
     void unusedAttached();
     void urlString();
+    void valueTypeArgument();
     void valueTypeBehavior();
     void valueTypeLists();
     void valueTypeProperty();
@@ -4956,6 +4957,18 @@ void tst_QmlCppCodegen::urlString()
     QCOMPARE(rootObject->objectName(), QLatin1String("http://dddddd.com"));
 }
 
+void tst_QmlCppCodegen::valueTypeArgument()
+{
+    QTest::ignoreMessage(QtMsgType::QtDebugMsg, "Reading l.i=5");
+
+    QQmlEngine engine;
+    QQmlComponent component(&engine, QUrl(u"qrc:/qt/qml/TestTypes/ValueTypeArgument.qml"_s));
+
+    QVERIFY2(component.isReady(), qPrintable(component.errorString()));
+    QScopedPointer<QObject> rootObject(component.create());
+    QVERIFY(rootObject);
+}
+
 void tst_QmlCppCodegen::valueTypeBehavior()
 {
     QQmlEngine engine;