Example of generated code:

    if (!PyBytes_Check(args[15])) {
        _PyArg_BadArgument("replace", 16, "bytes", args[15]);
        goto exit;
    }

Error message:

TypeError: replace() argument 16 must be bytes, not tuple

It is the 'lnotab' parameter which is a keywoard-only parameter. I expect the parameter name in the error message.

Note: I got this error while implementing bpo-37032.

With the attached PR, the error message is now:

>>> def f(): pass
... 
>>> code = f.__code__
>>> code.replace(co_lnotab=4)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: replace() argument 'co_lnotab' must be bytes, not int

This is a bug. I intentionally committed the simpler code, but forgot to fix it later.

> This is a bug. I intentionally committed the simpler code, but forgot to fix it later.

I suggest to also apply the fix to 3.8 in that case.

New changeset 4901fe274bc82b95dc89bcb3de8802a3dfedab32 by Serhiy Storchaka (Rémi Lapeyre) in branch 'master':
bpo-37034: Display argument name on errors with keyword arguments with Argument Clinic. (GH-13593)
https://github.com/python/cpython/commit/4901fe274bc82b95dc89bcb3de8802a3dfedab32

New changeset 96631dcb11c2786f470d4586bf23ecca14361506 by Serhiy Storchaka in branch '3.8':
[3.8] bpo-37034: Display argument name on errors with keyword arguments with Argument Clinic. (GH-13593). (GH-15599)
https://github.com/python/cpython/commit/96631dcb11c2786f470d4586bf23ecca14361506

Thank you Rémi!

Thanks, that's a great enhancement!