Python 3 has support for type annotations. Normally when we call a function with too few arguments then it returns a TypeError message with required arguments name but it gives no information about the type of the variables when there are type annotations for the function. I have added a little patch to return type annotations for the parameters and return type when there are type errors. This doesn't affect the existing code but improves on the code that has type annotations. My C skills are low and there is a lot of room for improvement. Feedback welcome. The code is available at https://github.com/tirkarthi/cpython/tree/error-message-annotations . Gist : https://gist.github.com/tirkarthi/8e6e01fde74398cac7a4eb7246169956 Sorry for the double post if you have received any since my previous post was rejected as I have not subscribed to the group. A sample run is as below : # foo_signature.py from typing import List, Dict import sys def get_profile_a(user_id: int, likes: Dict[str, int]) -> Dict[str, int]: return {'user_id': user_id, 'likes': len(likes)} def get_profile_b(user_id, likes): return {'user_id': user_id, 'likes': len(likes.keys())} if len(sys.argv) > 1: get_profile_a() else: get_profile_b() # Without type hinting cpython git:(error-message-annotations) ./python foo_signature.py Traceback (most recent call last): File "../backups/foo_signature.py", line 13, in <module> get_profile_b() TypeError: get_profile_b() missing 2 required positional arguments: 'user_id' and 'likes' # With type hinting patch cpython git:(error-message-annotations) ./python foo_signature.py 1 Traceback (most recent call last): File "../backups/foo_signature.py", line 11, in <module> get_profile_a() TypeError: get_profile_a() missing 2 required positional arguments: 'user_id' and 'likes' annotation: (user_id: <class 'int'>, likes: typing.Dict[str, int], return: typing.Dict[str, int])