Valgrind says
==27114== Invalid read of size 8
==27114== at 0x56293E0: QQmlContext::isValid() const (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x56DF243: QQmlDelegateModelPrivate::emitChanges() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x56E5361: QQmlDelegateModel::_q_modelReset() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x5707524: QQmlDelegateModel::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x5707AEE: QQmlDelegateModel::qt_metacall(QMetaObject::Call, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x63E29CC: QMetaObject::activate(QObject*, int, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x6359EFD: QAbstractItemModel::endResetModel() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x4031B2: MyModel::~MyModel() (main.cpp:17)
==27114== by 0x4043A6: QQmlPrivate::QQmlElement<MyModel>::~QQmlElement() (in /home/tsdgeos_work/test/test)
==27114== by 0x4043F7: QQmlPrivate::QQmlElement<MyModel>::~QQmlElement() (qqmlprivate.h:106)
==27114== by 0x63E136B: QObjectPrivate::deleteChildren() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x63EA0EB: QObject::~QObject() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x4FC74C5: QQmlPrivate::QQmlElement<QQuickItem>::~QQmlElement() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A169: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A1D8: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x402C17: main (main.cpp:36)
==27114== Address 0x1b6ac9f8 is 8 bytes inside a block of size 16 free'd
==27114== at 0x4C2C2BC: operator delete(void*) (vg_replace_malloc.c:503)
==27114== by 0x5629BF0: QQmlContextData::destroy() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x560D238: QQmlPrivate::qdeclarativeelement_destructor(QObject*) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x4FC74BD: QQmlPrivate::QQmlElement<QQuickItem>::~QQmlElement() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A169: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A1D8: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x402C17: main (main.cpp:36)
==27114==
==27114== Invalid read of size 8
==27114== at 0x56293E4: QQmlContext::isValid() const (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x56DF243: QQmlDelegateModelPrivate::emitChanges() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x56E5361: QQmlDelegateModel::_q_modelReset() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x5707524: QQmlDelegateModel::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x5707AEE: QQmlDelegateModel::qt_metacall(QMetaObject::Call, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x63E29CC: QMetaObject::activate(QObject*, int, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x6359EFD: QAbstractItemModel::endResetModel() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x4031B2: MyModel::~MyModel() (main.cpp:17)
==27114== by 0x4043A6: QQmlPrivate::QQmlElement<MyModel>::~QQmlElement() (in /home/tsdgeos_work/test/test)
==27114== by 0x4043F7: QQmlPrivate::QQmlElement<MyModel>::~QQmlElement() (qqmlprivate.h:106)
==27114== by 0x63E136B: QObjectPrivate::deleteChildren() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x63EA0EB: QObject::~QObject() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x4FC74C5: QQmlPrivate::QQmlElement<QQuickItem>::~QQmlElement() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A169: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A1D8: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x402C17: main (main.cpp:36)
==27114== Address 0x1bafa150 is 112 bytes inside a block of size 144 free'd
==27114== at 0x4C2C2BC: operator delete(void*) (vg_replace_malloc.c:503)
==27114== by 0x63EA11F: QObject::~QObject() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x5629D48: QQmlContext::~QQmlContext() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x5629BF0: QQmlContextData::destroy() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x560D238: QQmlPrivate::qdeclarativeelement_destructor(QObject*) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x4FC74BD: QQmlPrivate::QQmlElement<QQuickItem>::~QQmlElement() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A169: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A1D8: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x402C17: main (main.cpp:36)
==27114==
==27114== Invalid read of size 8
==27114== at 0x56293ED: QQmlContext::isValid() const (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x56DF243: QQmlDelegateModelPrivate::emitChanges() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x56E5361: QQmlDelegateModel::_q_modelReset() (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x5707524: QQmlDelegateModel::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x5707AEE: QQmlDelegateModel::qt_metacall(QMetaObject::Call, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x63E29CC: QMetaObject::activate(QObject*, int, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x6359EFD: QAbstractItemModel::endResetModel() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x4031B2: MyModel::~MyModel() (main.cpp:17)
==27114== by 0x4043A6: QQmlPrivate::QQmlElement<MyModel>::~QQmlElement() (in /home/tsdgeos_work/test/test)
==27114== by 0x4043F7: QQmlPrivate::QQmlElement<MyModel>::~QQmlElement() (qqmlprivate.h:106)
==27114== by 0x63E136B: QObjectPrivate::deleteChildren() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x63EA0EB: QObject::~QObject() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.3.0)
==27114== by 0x4FC74C5: QQmlPrivate::QQmlElement<QQuickItem>::~QQmlElement() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A169: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A1D8: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x402C17: main (main.cpp:36)
==27114== Address 0x1baf89d8 is 8 bytes inside a block of size 168 free'd
==27114== at 0x4C2C2BC: operator delete(void*) (vg_replace_malloc.c:503)
==27114== by 0x560D238: QQmlPrivate::qdeclarativeelement_destructor(QObject*) (in /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.3.0)
==27114== by 0x4FC74BD: QQmlPrivate::QQmlElement<QQuickItem>::~QQmlElement() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A169: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x505A1D8: QQuickView::~QQuickView() (in /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.3.0)
==27114== by 0x402C17: main (main.cpp:36)

on the attached code.

I understand emitting reset from the destructor is not very useful, but in the real world code we are just reusing the clean() function that is also called in other instances that is not the destructor so it is very handy that it does not crash (it didn't use to in Qt 5.2)

I'll attach main.cpp main.qml and test.pro