Dim inactive regions (C/C++)

[nuid64]

It would be nice to have highlighted only code which will be compiled. Seen this feature in VSCode cland extension

[the-mikedavis]

I assume that clang implements this using diagnostic tags like rust-analyzer does. So this should have been implemented in #9780. You can try using the latest master branch along with a theme that defines diagnostic.unnecessary, for example the default theme after that PR was merged:

helix/theme.toml

Lines 83 to 84 in 64c1de1

	"diagnostic.unnecessary" = { modifiers = ["dim"] }
	"diagnostic.deprecated" = { modifiers = ["crossed_out"] }

[nuid64]

Oh, that's cool. For some reason this doesn't work with clangd. I can't see it sends any diagnostic tags in helix log

[pascalkuthe]

I think clangd does this using semantic highlighting which we don't support (duplicate of #5589).

Could be nice to add support for diagnostic tags upstream instead. For example RA supports semantic highlights yet uses diagnostic tags aswell.