Fix lint error

[pokey]

I believe this is what was intended. I think the linter caught a genuine error here, because I believe 0 actually would refer to commit here. At least that's what the linter suggests would be equivalent. Guessing maybe the map gets sorted alphabetically, so then 0 would refer to commit?

Looks like there's no tests for this error message, though, as the tests passed whether I put {commit} or {source} here

[arxanas]

Thanks! Not sure why this wasn't caught in CI previously.

[pokey]

I think it may be caused by a recent rust upgrade; I wasn't getting it locally either and then I upgraded rust and started seeing it locally as well