[issue1621] Do not assume signed integer overflow behavior

[Xiang Zhang]

Xiang Zhang added the comment:

I agree. For multibytecode, how about switching the positions of the two checks? If npendings + ctx->pendingsize overflows, the result can be anything, larger, smaller than or equal to MAXDECPENDING. For ast, although a SystemError may be raised but the message seems not obvious to the reason.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue1621>
_______________________________________