CPython has been created in 1990. In 1990, it made sense to use C macros. But nowadays, inlined functions can be used instead:
"Python versions greater than or equal to 3.6 use C89 with several select C99 features: (...) static inline functions"
https://www.python.org/dev/peps/pep-0007/#c-dialect
I propose to convert 4 macros to inlined functions:
* PyObject_INIT(), PyObject_INIT_VAR()
* _Py_NewReference(), _Py_ForgetReference()
Advantages:
* Functions use regular C syntax
* No more corner cases ("traps") of macros
* Function arguments have a type
Drawbacks:
* Require a specific type can introduce compiler warnings if the caller doesn't pass the proper type (PyObject* or PyVarObject*). _Py_NewReference() and _Py_ForgetReference() seem to be properly used, but not PyObject_INIT() and PyObject_INIT_VAR().
The two attached PRs implements these changes.