Diagnostic formatter should highlight trivia in between consecutive highlight nodes

[ahoppen]

Currently, if a diagnostic has two nodes to highlight, it will highlight them individually, leaving the trivia in between them non-highlighted. The easiest way to see this is by running

swift-parser-cli print-diags -s 'for x = 1; x < 10; x++ {}'

Note that the space between x and = should also be highlighted.

[ahoppen]

Tracked in Apple’s issue tracker as rdar://115600611

[Matejkob]

I'm on it

[Matejkob]

I've implemented a solution to this issue and now I'd like to add unit tests to ensure that all edge cases are covered. Do we have a straightforward way to create Diagnostic.highlights efficiently in unit tests and attach them to a given syntax tree? I couldn't find anything like that in the codebase.

[ahoppen]

I don’t think there is. This comment that I posted just now might be relevant.

[Matejkob]

This comment that I posted just now might be relevant.

Pardon? 😅

[ahoppen]

Forgot to add the link: #2238 (comment)