Formatting attribute item with leading comma removes entire item

[ayazhafiz]

Running rustfmt (at least since a5cb5d2) on a code like

#[derive(, Eq)]
struct A {}

results in

#[derive()]
struct A {}

Is this intentional?

[calebcartwright]

Thanks for the report @ayazhafiz, but this is a duplicate of #4029/#3898. The issue has been fixed but not yet released (it will be in the next version of rustfmt)