Hi, (First time poster. Apologies in advance if I'm not following the appropriate protocol, or if this has been posted already)
I noticed an issue on Windows when debugging an issue in scipy <https://github.com/scipy/scipy/issues/4907>, but I think it might be a little more general. In some places in the generated code, it looks like intermediate integral variables are declared with type long, even when long is too small to hold necessary value. For example, with the code pasted below, the value n+1 is stored in a variable of type long (using Cython 0.22.1) before being supplied to F.__getitem__. This is especially pertinent on Windows (32 bit and 64 bit) and 32-bit linux, where longs are 32-bits, so you get an overflow for a program like the example below. The result is that it prints 1 instead of the expected value, 2**53+1 = 9007199254740993. But this same issue comes up basically whenever you do arithmetic on an array index in 64-bit Windows, for indices larger than 2**31-1, since sizeof(long) << sizeof(void*). ``` from libc.stdint cimport int64_t class F(object): def __getitem__(self, i): print(i) cdef int64_t n = 2**53 f = F() f[n+1] ```
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