1 files changed, 20 insertions, 5 deletions
diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index e4fb54f0ff..91650f16e2 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -75,10 +75,13 @@
 #include <QtCore/qatomic.h>
 #include <QtCore/qmetaobject.h>
 #include <QtCore/qabstractitemmodel.h>
+#include <QtCore/qloggingcategory.h>
 
 #include <vector>
 QT_BEGIN_NAMESPACE
 
+Q_LOGGING_CATEGORY(lcBindingRemoval, "qt.qml.binding.removal", QtWarningMsg)
+
 // The code in this file does not violate strict aliasing, but GCC thinks it does
 // so turn off the warnings for us to have a clean build
 QT_WARNING_DISABLE_GCC("-Wstrict-aliasing")
@@ -458,10 +461,23 @@ void QObjectWrapper::setProperty(ExecutionEngine *engine, QObject *object, QQmlP
         }
     }
 
-    if (newBinding)
+    if (newBinding) {
         QQmlPropertyPrivate::setBinding(newBinding);
-    else
+    } else {
+        if (Q_UNLIKELY(lcBindingRemoval().isInfoEnabled())) {
+            if (auto binding = QQmlPropertyPrivate::binding(object, QQmlPropertyIndex(property->coreIndex()))) {
+                Q_ASSERT(!binding->isValueTypeProxy());
+                const auto qmlBinding = static_cast<const QQmlBinding*>(binding);
+                const auto stackFrame = engine->currentStackFrame();
+                qCInfo(lcBindingRemoval,
+                       "Overwriting binding on %s::%s at %s:%d that was initially bound at %s",
+                       object->metaObject()->className(), qPrintable(property->name(object)),
+                       qPrintable(stackFrame.source), stackFrame.line,
+                       qPrintable(qmlBinding->expressionIdentifier()));
+            }
+        }
         QQmlPropertyPrivate::removeBinding(object, QQmlPropertyIndex(property->coreIndex()));
+    }
 
     if (!newBinding && property->isVarProperty()) {
         // allow assignment of "special" values (null, undefined, function) to var properties
@@ -1044,7 +1060,6 @@ void QObjectWrapper::destroyObject(bool lastCall)
         }
     }
 
-    h->internalClass = 0;
     h->~Data();
 }
 
@@ -1797,7 +1812,7 @@ QV4::ReturnedValue CallArgument::toValue(QV4::ExecutionEngine *engine)
 ReturnedValue QObjectMethod::create(ExecutionContext *scope, QObject *object, int index)
 {
     Scope valueScope(scope);
-    Scoped<QObjectMethod> method(valueScope, scope->d()->engine->memoryManager->allocObject<QObjectMethod>(scope));
+    Scoped<QObjectMethod> method(valueScope, valueScope.engine->memoryManager->allocObject<QObjectMethod>(scope));
     method->d()->setObject(object);
 
     if (QQmlData *ddata = QQmlData::get(object))
@@ -1848,7 +1863,7 @@ QV4::ReturnedValue QObjectMethod::method_toString(QV4::ExecutionContext *ctx) co
         result = QLatin1String("null");
     }
 
-    return ctx->d()->engine->newString(result)->asReturnedValue();
+    return ctx->engine()->newString(result)->asReturnedValue();
 }
 
 QV4::ReturnedValue QObjectMethod::method_destroy(QV4::ExecutionContext *ctx, const Value *args, int argc) const