Hi,

I've reviewed the latest patch.
I have a more general question: the patch sprinkles some Py_INIT_BOUNDS() calls in various places. What the macro does is set the pointer's bounds to "INIT", which basically means disable any checks (the pointer is allowed to access all memory). Is there a reason for that? MPX checks for out-of-bounds accesses, so setting pointer bounds to "INIT" seems to defeat the point.

(if MPX otherwise complains about out-of-bounds accesses in CPython, perhaps they are genuine bugs that deserve fixing, or perhaps the annotations in the patch are not good enough)