Hum, there are two things and maybe we are not talking about the same thing.

* (A) Modifying macros defined in the Python C API (Include/ header files) doing cast on their arguments to use CAST macros
* (B) Modify C code doing casts to use CAST macros

I created this issue for (A). I propose to do (B), but this part is optional.

Mark, Ken: are you fine with (A)? Is your concern about (B)?

But modifying macros to remove the cast of their argument is out of the scope of this issue. As I wrote, it would add compiler warnings, something that I would like to avoid. See:
https://peps.python.org/pep-0670/#cast-pointer-arguments