Rustup: "error: " is printed twice

[camelid]

Problem
"error: " is printed twice:

$ rustup toolchain list --installed
error: error: Found argument '--installed' which wasn't expected, or isn't valid in this context

USAGE:
    rustup toolchain list [FLAGS]

For more information try --help

Steps

1. Run rustup toolchain list --installed. Or just run it with any flag that doesn't make sense: rustup --blah

Possible Solution(s)

Notes

Output of rustup --version: rustup 1.22.1 (b01adbbc3 2020-07-08)

[camelid]

I think I have a fix. Hmm, or not...

[kinnison]

I believe this is a dup of #2492 which was fixed in #2496.

[camelid]

Indeed, this is fixed on master.

[kinnison]

Rustup 1.23.0 is now out.