[BUG] Wrong Warning

[YoSTEALTH]

Describe the bug

Both i and len are unsigned

Code to reproduce the behaviour:

cdef:
    unsigned int i
    __u16        len

if i < len-1:

warning: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Wsign-compare]
22194 |         __pyx_t_1 = (__pyx_cur_scope->__pyx_v_i < (__pyx_cur_scope->__pyx_v_self->__pyx_base.len - 1));

[da-woods]

I think this is just C rules (described in https://en.cppreference.com/w/c/language/conversion).

If the signed type can represent all values of the unsigned type, then the operand with the unsigned type is implicitly converted to the signed type.

I assume __u16 is a 16-bit unsigned int. The 1 is a signed int (either 32 or 64 bit depending on the platform) so I think that rule will apply and len - 1 will also be a signed int.

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Not completely sure though because I haven't read and understood all of that page. But I'm fairly sure this is mostly C and not Cython

[YoSTEALTH]

I can avoid the error by setting i to be __u16 as well. I just figure you guys should know about this.