Assertion failure in QCoreApplication::sendEvent if a child object of a parent object moved to different thread is destroyed in the parent destructor

• Define a QObject-derived parent class with a child object of QObject-derived class
• When the child object is created, set its parent to be the parent object
• In the parent class destructor explicitly destroy the child object (or let the compiler do it if the object is embedded into the parent)
• Create an instance of the parent class
• Create a new thread
• Move the parent class instance to the thread with QObject::moveToThread
• Start the thread and wait for it to finish
• Destroy the parent class instance

Expected:

• The parent and child objects will be destroyed cleanly

Actual:

• The child object destruction fails with assertion
  ASSERT failure in QCoreApplication::sendEvent: "Cannot send events to objects owned by a different thread. Current thread xxxxxxx. Receiver '' (of type 'ttt') was created in thread yyyyyyy", file kernel/qcoreapplication.cpp, line 405

Notes:

• If the child is held by a pointer variable, which is not deleted in the parent class destructor there is no assertion failure
• The problem does not exist in Qt 4.7.2 (-0ubuntu6.2), which makes this seem like a regression or at least a change in behavior.
• See also the attached test program.