Question about arg! macro syntax, conflict with rustfmt

[sjmik]

This is kind of two questions in one.

If I try to use the arg! macro like

arg!(-s --"some-flag")

rustfmt with default settings will turn it into

arg!(-s - -"some-flag")

If another piece is added, rustfmt leaves it alone

arg!(-s --"some-flag" <FILE>) // Works
arg!(-s --"some-flag" "") // Works

Do you think this is an issue with rustfmt or something with the macro?
I seriously do not envy anyone writing macros like these... 😅
For anyone who understands how it works, can you explain why this is the case?

Is it just a limitation of how macros work, or something else?

[epage]

Formatting the inside of macros is difficult because there can be valid rust code that people want formatted, a DSL people don't want formatted, or even both. I don't envy rustfmt in having to deal with it.