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Incorrect warning when assign an unsigned integer member #114388

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@serhiy-storchaka

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@serhiy-storchaka

Assigning a negative value to an unsigned integer member can emit a RuntimeWarning.

$ ./python -Wa
>>> import _testcapi
>>> ts = _testcapi._test_structmembersType_NewAPI()
>>> ts.T_UBYTE = -42
<stdin>:1: RuntimeWarning: Truncation of value to unsigned char
>>> ts.T_USHORT = -42
<stdin>:1: RuntimeWarning: Truncation of value to unsigned short
>>> ts.T_UINT = -42
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field
<stdin>:1: RuntimeWarning: Truncation of value to unsigned int
>>> ts.T_ULONG = -42
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field

(And for T_ULONGLONG it raises an OverflowError, but this is perhaps another issue).

The first issue is that it emits two warnings for T_UINT. It is also weird that warnings are different.

The second issue is that if the value is not an int subclass, it emits a warning also for positive values for T_UINT and T_ULONG:

>>> class Index:
...     def __init__(self, value):
...         self.value = value
...     def __index__(self):
...         return self.value
... 
>>> ts.T_UBYTE = Index(42)
>>> ts.T_USHORT = Index(42)
>>> ts.T_UINT = Index(42)
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field
>>> ts.T_ULONG = Index(42)
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field

(No warning is emitted for assigning a negative index to T_ULONGLONG, but this is perhaps another issue).

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    3.11only security fixes3.12only security fixes3.13bugs and security fixesinterpreter-core(Objects, Python, Grammar, and Parser dirs)

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