bug#69625: 30.0.50; [PATCH] rust-ts-mode doesn't fontify some enum

[Yuan Fu <casouri@gmail.com>]

> On Mar 14, 2024, at 6:52 PM, Dmitry Gutov <dmitry@gutov.dev> wrote:
> 
> On 09/03/2024 05:50, Randy Taylor wrote:
>> VariantA gets highlighted as a type and not a function at level 3 because that
>> level doesn't support functions, but does support types. Maybe that could be
>> considered a bug in that it shouldn't be highlighted at all for level 3?
> 
> Probably.
> 
>> I'm not sure how worth it would be to do something about that though, or how
>> easy.
> 
> Same. I haven't looked into it.
> 
>> For VariantC, our (and tree-sitter's) best guess is that it's a variable.
>> We can't really know it's a type without guessing - like assuming a capitalized
>> identifier is a type, and I don't think that's something we can assume. People
>> can have capitalized functions and variables even if that goes against Rust's
>> usual style. Perhaps as a compromise we could introduce a variable (or something)
>> that lets the user specify that all capitalized identifiers should be treated as
>> types? Maybe it even makes sense to default it to that behaviour since I believe
>> most Rust code follows that style.
> 
> We do have some rules already that are based off whether an identifier is capitalized. I.e. some for use_as_clause, and another for highlighting an identifier with font-lock-constant-face if it's ALL_CAPS. So it might be logical to carry on with that approach.
> 
> If the style is consistent enough across the ecosystem, of course.
> 
> We could add a variable too, but that'd make the rules more complex so it would be helpful to understand first whether there are users who would benefit.

For some reason I couldn’t see Randy’s messages. So sorry if I missed anything. I suggest we go ahead with guessing and add the variable if enough people complain. Personally speaking I believe the vast majority of Rust community wouldn’t write Rust code with capitalized variable and non-capitalized types. The Rust community is very much inclined to the standard style, AFAICT.

Yuan