LSP diagnostics without severity levels render as confusing inline blocks resembling block cursor. Themes missing fallback diagnostic.

[k4lizen]

I use the theme ayu_mirage. As of ~recent, when an inline warning pops up it highlights the first character that the warning refers to. This is pretty cool!

But!

It is hard for me to visually tell where the cursor is amongst the warnings. The cursor block is a bit darker, and also that line is highlighted which does help, but really, the contrast between the warning highlights and the cursor highlight should be much better. The problem is exacerbated when using multiple cursors and having to keep track of them all - it can get really unwieldy.

This problem is also apparent on lots of other themes. Here are two themes where I think this particular problem is handled nicely.
monokai_pro_spectrum
The warning highlights have low opacity.

gruvbox
A little squigly is used instead of the whole charater being highlighted. This is pretty good also.

[a3lem]

Same in everforest-light and pretty much every light theme. I'm constantly losing my cursor.

[a3lem]

@k4lizen, seeing as you're also seeing this with Python, are you using the Ruff language server by any chance?

I just noticed that if I disable it and use basedpyright/pylsp instead, these cursor-like blocks go away. Very odd

[a3lem]

Okay, this is interesting: the offending Ruff diagnostics do not have a severity level

[a3lem]

This seems to be related to https://docs.astral.sh/ruff/editors/settings/#showsyntaxerrors.

2 workarounds

1. Add the following to the Ruff lsp config section:

config = { settings = { showSyntaxErrors = false} }

2. Add a fallback diagnostic level to your theme

"diagnostic" = { underline = { color = "blue", style = "curl" } }

[k4lizen]

@a3lem
yup I am using ruff. Thanks for the workarounds, the second workaround works great. Just checking but is there a way to modify a theme I'm using or do I have to use inherits = "ayu_mirage" in a new theme?

[a3lem]

Happy to hear! You can do either. While experimenting I just edited the builtin theme files in-place. On my install, they're located under $HOME/.config/helix/runtime/themes/ (aka $HELIX_RUNTIME/themes/). They're owned by Helix though, and are subject to be overwritten (or create merge conflicts if you're building locally). To play it safe, I've created a new theme in $HOME/.config/helix/themes that inherits from the builtin theme.

Example:

inherits = "everforest_light"

diagnostic = { underline = { color = "blue", style = "curl" } }

Btw, now that we've identified the cause of this issue, would you mind maybe updating the title, so that others (including maintainers) will be more likely to find it? A suggestion: LSP diagnostics without severity levels render as confusing inline blocks resembling block cursor. Themes missing fallback diagnostic.