I'm not sure if this is a bug or a feature request, but in order to support auto-completion for argparse (see #628) in other language servers (the default vscode one, Microsoft I think?) I like to create a marker class defining the acceptable properties and then manually annotate the type signature of the parse_args method with the class, so it's used when auto-completing. Pylance, however, ignores my manual annotation and continues to assume the type is the return type from parse_args (which is Namespace).

Note: I don't expect Pylance to special-case code for argparse. I simply want it to use my Args class as the type for all inference decisions, even if I make a mistake and my Args class gets out of sync with how I've actually configured my argparse parser.

This is a minimal reproduction:

import argparse

class Args:
    command: bool = None

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--command', action='store_true')
    args: Args = parser.parse_args()

The inferred type is Namespace, but it would be nice if it said Args (however, the default language server also shows Namespace despite the annotation, so this is less important than auto-complete support):

This is the auto-complete output from the Pylance language server. There is no suggestion for command.

This is the auto-complete output from the default language server, which includes command as a suggestion: