Should ast::Position use `Symbol` instead of `str`?

[oli-obk]

rust/src/libfmt_macros/lib.rs

Line 74 in 258e3b3

ArgumentNamed(&'a str),

is compared against symbols in clippy, and I believe in rustc many uses could also be comparing against symbols. Is this something we should do @nnethercote ?

[nnethercote]

Possibly. The best way to decide is to simply try it and see how well it works. Sometimes switching to a symbol makes everything fall out nicely. Sometimes there are a bunch of follow-on changes required but it still ends up nice. Sometimes it ends up making the code more complicated and a string is better.

[nnethercote]

Hmm, libfmt_macros currently doesn't depend on any crates, and with this change it would depend on libsyntax_pos.

[oli-obk]

libfmt_macros also custom rolls its own Span type. Having a dependency on libsyntax_pos can possibly make a lot of things simpler, but I haven't checked in depth.

cc @estebank

[estebank]

I believe that should likely be appropriate. CC me on the PRs to take a look at them.