I'm getting sporadic crashes when deleting quick items. Unfortunately, there's no test application to demonstrate, but I'll try to explain. It involves a lot of loading/unloading of QML items with Loader
See qproperty.cpp file.
QBindingStoragePrivate::reallocate allocates memory for QBindingStorageData at least 8 QBindingStoragePrivate::Pair, but doesn't create actual Pair structs. So the memory is filled with zeroes.
And QBindingStoragePrivate::destroy contains a for loop until size.
I just wonder why it doesn't crash every single time. And why it doesn't crash on dereferencing p immediately. Anyway, it looks like a huge issue.
I can suggest checking p for NULL
or looping until d->used instead of d->size (if Pairs are guaranteed to be consequent in memory.