First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the Typer documentation, with the integrated search.
• I already searched in Google "How to X in Typer" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to Typer but to Click.

Commit to Help

• I commit to help with one of those options 👆

Example Code

Not working:
    myparam: str = typer.Argument(
        "",
        shell_complete=my_autocomplete,
    )

Working:
    myparam: str = typer.Option(
        "",
        shell_complete=my_autocomplete,
    ),

Description

I'm trying to enable shell complete on an Argument but it does not work. On the opposite with Options everything is working as expected

I think that the same problem was already in the previous versions of typer (so that it is NOT introduced by typer 0.4.0 & click 8... but i'm not totally sure about that)

Based on tests on click, shell_complete on arguments should work: https://github.com/pallets/click/blob/48cb86d85fc1abfcf1478ee660e42aaa5382fd64/examples/completion/completion.py#L25

in typer I can't find tests with arguments, I only found this with option https://github.com/tiangolo/typer/blob/a1520dcda685220a9a796288f5eaaebd00d68845/tests/assets/compat_click7_8.py#L20

Operating System

Linux

Operating System Details

Ubuntu 20.04

Typer Version

0.4.0

Python Version

Python 3.9.5

Additional Context

click 8.0.1