Type macros may follow a different naming convention

[dtolnay]

https://github.com/rust-lang-nursery/api-guidelines/issues/135#issuecomment-343698387 suggests a nice one:

I've been using PascalCase! for macros that expand into types. (e.g. Array![i32; 5; 4; 3] which expands into [[[i32; 3]; 4]; 5])

I did not consider type macros when adding a case convention for macros in C-CASE. I have also never used a type macro myself. Will need to survey the ecosystem and see whether PascalCase! for type macros would be a good recommendation.

[KodrAus]

This seems like an amendment we'd want to make now. In the intervening years I think PascalCase has emerged as a standard for type macros (like syn::Token!).

[KodrAus]

@rfcbot fcp merge

[KodrAus]

@rfcbot fcp merge

This proposes amending our naming conventions to recommend type macros use PascalCase naming instead of snake_case.

[rfcbot]

Team member @KodrAus has proposed to merge this. The next step is review by the rest of the tagged team members:

• [x] @Amanieu
• [x] @BurntSushi
• [x] @KodrAus
• [x] @dtolnay
• [ ] @m-ou-se
• [x] @sfackler
• [ ] @withoutboats

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[CodesInChaos]

Are there any type macros in the standard library already?

[PlasmaPower]

Yes, there's vec! and format_args!, both using snake case instead of pascal case.

Edit: oops, misunderstood the issue

[sfackler]

Both of those macros expand into values, not types.

[rfcbot]

:bell: This is now entering its final comment period, as per the review above. :bell:

psst @KodrAus, I wasn't able to add the final-comment-period label, please do so.

[rfcbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

The RFC will be merged soon.

psst @KodrAus, I wasn't able to add the finished-final-comment-period label, please do so.