Node method to get span for the whole node

[stoically]

This should probably span all children nodes as well? Like in the case of e.g. <><div /></> the fragment span should be 0 to 12? Is that what you'd expect from such method, @zetanumbers?

If possible add a field containing the span to node types.

[zetanumbers]

I will link to this issue this inside of my code. Thank you.

[zetanumbers]

Btw I saw for example NodeName straightforward implementing span method. You should consider implementing the syn::spanned::Spanned trait instead.

[stoically]

Btw I saw for example NodeName straightforward implementing span method. You should consider implementing the syn::spanned::Spanned trait instead.

Thanks for the hint. While reading https://docs.rs/syn/latest/syn/spanned/trait.Spanned.html, I realized that Spanned is automatically implemented if ToTokens is implemented, which is already the case for NodeName. So I can just drop the manual span implementation.

[stoically]

It seems to implement a span method for a whole node it'd need the https://docs.rs/proc-macro2/latest/proc_macro2/struct.Span.html#method.join method, which currently is still nightly only, since it depends on rust-lang/rust#54725.

Unless I'm missing a different way to construct a span from a start and end span.

[danheuck]

While this can't be implemented properly in stable until Span::join() is stabilized, it would be nice for diagnostic purposes to be able to get some span for every kind of node even if it doesn't actually cover the entire node. I think the worst case here is fragment, but even there we can default to the start of the opening tag which definitely beats using Span::call_site(). Happy to attempt a PR if you want.

[stoically]

@danheuck I like the idea and would be happy to review a PR for it. This could probably also help with #12, where the span would help with formatting custom errors.

[stoically]

Only thing I'm a bit unsure about is in which cases it actually makes sense to store an additional span, given that the Expressions already give access to spans.