Fix lookup of methods in the scope object

Commit 939014cb9cad2f3357f47b28a4580397c17b913c improved performance of
property lookups beyond the scope object, with the unfortunate
side-effect that the previously polymorphic lookup of methods broke.

Fix this by moving the handling to the caller side and falling back to
the string lookup for functions.

Fixes: QTBUG-71204
Change-Id: I2d9924034a9c14e7d161fa49d51b1f876ab5bc0f
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

3 files changed, 36 insertions, 5 deletions

diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 883b21ab07..9021fd0284 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -1947,11 +1947,7 @@ QQmlPropertyData *JSCodeGen::lookupQmlCompliantProperty(QQmlPropertyCache *cache
 {
     QQmlPropertyData *pd = cache->property(name, /*object*/nullptr, /*context*/nullptr);
 
-    // Q_INVOKABLEs can't be FINAL, so we have to look them up at run-time
-    if (!pd || pd->isFunction())
-        return nullptr;
-
-    if (!cache->isAllowedInRevision(pd))
+    if (pd && !cache->isAllowedInRevision(pd))
         return nullptr;
 
     return pd;
@@ -2280,6 +2276,10 @@ QV4::Compiler::Codegen::Reference JSCodeGen::fallbackNameLookup(const QString &n
     if (_scopeObject) {
         QQmlPropertyData *data = lookupQmlCompliantProperty(_scopeObject, name);
         if (data) {
+            // Q_INVOKABLEs can't be FINAL, so we have to look them up at run-time
+            if (data->isFunction())
+                return Reference::fromName(this, name);
+
             Reference base = Reference::fromStackSlot(this, _qmlContextSlot);
             Reference::PropertyCapturePolicy capturePolicy;
             if (!data->isConstant() && !data->isQmlBinding())
@@ -2293,6 +2293,10 @@ QV4::Compiler::Codegen::Reference JSCodeGen::fallbackNameLookup(const QString &n
     if (_contextObject) {
         QQmlPropertyData *data = lookupQmlCompliantProperty(_contextObject, name);
         if (data) {
+            // Q_INVOKABLEs can't be FINAL, so we have to look them up at run-time
+            if (data->isFunction())
+                return Reference::fromName(this, name);
+
             Reference base = Reference::fromStackSlot(this, _qmlContextSlot);
             Reference::PropertyCapturePolicy capturePolicy;
             if (!data->isConstant() && !data->isQmlBinding())
diff --git a/tests/auto/qml/qqmllanguage/data/polymorphicFunctionLookup.qml b/tests/auto/qml/qqmllanguage/data/polymorphicFunctionLookup.qml
new file mode 100644
index 0000000000..4a3cc52793
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/polymorphicFunctionLookup.qml
@@ -0,0 +1,14 @@
+import QtQml 2.0
+QtObject {
+    id: root
+    property bool testFunc;
+    property bool ok: false
+    property QtObject subObject: QtObject {
+        function testFunc()
+        {
+            root.ok = true
+        }
+
+        Component.onCompleted: testFunc()
+    }
+}
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 157fd500ad..7a8de739f4 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -298,6 +298,8 @@ private slots:
 
     void retrieveQmlTypeId();
 
+    void polymorphicFunctionLookup();
+
 private:
     QQmlEngine engine;
     QStringList defaultImportPathList;
@@ -5049,6 +5051,17 @@ void tst_qqmllanguage::retrieveQmlTypeId()
     QVERIFY(qmlTypeId("Test", 1, 0, "MyTypeObjectSingleton") >= 0);
 }
 
+void tst_qqmllanguage::polymorphicFunctionLookup()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("polymorphicFunctionLookup.qml"));
+    VERIFY_ERRORS(0);
+    QScopedPointer<QObject> o(component.create());
+    QVERIFY(!o.isNull());
+
+    QVERIFY(o->property("ok").toBool());
+}
+
 QTEST_MAIN(tst_qqmllanguage)
 
 #include "tst_qqmllanguage.moc"