_Py_HashPointer in Python/pyhash.c takes a pointer argument that can be made const.  This will let compiler and static analyzers know that the pointer's target is not modified.  You can also change calls to _Py_HashPointer that are down-casting pointers.

For example, in meth_hash in Objects/methodobject.c, this call can have the void * changed to const void *.

    y = _Py_HashPointer((void*)(a->m_ml->ml_meth));