Cargo expand fails to format code with documentation comments

[Robbepop]

I encountered a problem with documentation comments in Rust code that cause cargo expand to have unformatted blobs of code in its output.

In the picture above you can clearly see the entirely unformatted section of code next to some properly fomatted sections of code.
The whole things got fixed by manually converting some /// doc comments into normal comments // basically removing them.

I don't yet know whether this also happens with other attributes, however, note that the code does contain other attributes should as #[inline] or certain derives which got expanded properly.

Also note that cargo expand in fact seems to use rustfmt since cargo expand --ugly produces very different output that does not contain these entirely unformatted sections of code. However, code with cargo expand --ugly tends to look more ... ugly in general so it is also not a serious work around for me for now.

You can reproduce the problem with:

const _: () = {
    /// Breaks cargo-expand's formatting
    struct A;
};

This issue seems to be similar to #71.

[dtolnay]

I would be shocked if this were a cargo-expand issue. Could you report to rustfmt instead, with a minimized repro? Cargo-expand does not control what parts of the file rustfmt would run on.

[Robbepop]

@dtolnay The following minimal code snippet can be reproduced with cargo-expand tool but not with rustfmt tool.

const _: () = {
    /// Breaks cargo-expand's formatting
    struct A;
};

What do you think this could be the reason for this? I opened an issue for the rustfmt tool and the problem is that this code snippet really only works for reproducability with cargo-expand but not rustfmt.

Why cannot we handle this similar to #72 ?