JavaScript: Make "this" available in blocks inside arrow functions

Fixes: QTBUG-98039
Change-Id: I51ff36994fa0f3f3568c8114cb6841f677f64bc4
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit eeec9f03e9cf57e8cde311897f7e3e62a217da15)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 32 insertions, 5 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index fd55ce5562..20685e42f1 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -3065,12 +3065,17 @@ bool Codegen::visit(ThisExpression *)
     if (hasError())
         return false;
 
-    if (_context->isArrowFunction) {
-        Reference r = referenceForName(QStringLiteral("this"), false);
-        r.isReadonly = true;
-        setExprResult(r);
-        return false;
+    for (Context *parentContext = _context; parentContext; parentContext = parentContext->parent) {
+        if (parentContext->isArrowFunction) {
+            Reference r = referenceForName(QStringLiteral("this"), false);
+            r.isReadonly = true;
+            setExprResult(r);
+            return false;
+        }
+        if (parentContext->contextType != ContextType::Block)
+            break;
     }
+
     setExprResult(Reference::fromThis(this));
     return false;
 }
diff --git a/tests/auto/qml/qjsengine/tst_qjsengine.cpp b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
index c2abf83308..fb85be334e 100644
--- a/tests/auto/qml/qjsengine/tst_qjsengine.cpp
+++ b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
@@ -279,6 +279,7 @@ private slots:
 
     void uiLanguage();
     void urlObject();
+    void thisInConstructor();
 
 public:
     Q_INVOKABLE QJSValue throwingCppMethod1();
@@ -5470,6 +5471,27 @@ void tst_QJSEngine::urlObject()
     QCOMPARE(result2, url);
 }
 
+void tst_QJSEngine::thisInConstructor()
+{
+    QJSEngine engine;
+    const QJSValue result = engine.evaluate(R"((function() {
+        let a = undefined;
+        class Bugtest {
+            constructor() {
+                (() => {
+                    if (true) {
+                        a = this;
+                    }
+                })();
+            }
+        };
+        new Bugtest();
+        return a;
+    })())");
+    QVERIFY(!result.isUndefined());
+    QVERIFY(result.isObject());
+}
+
 QTEST_MAIN(tst_QJSEngine)
 
 #include "tst_qjsengine.moc"