Highlight deprecated symbols

[weskoerber]

I recently saw #1764 which highlights deprecated symbols in the completion list and I think this is an awesome feature.

Is it possible to extend that feature and highlight the deprecated symbols via diagnostics? For example, like rust_analyzer's deprecation highlights (note how foo() is hightlighted - er, struck-through - on line 6):

[Techatrix]

Showing an error when using a symbol that is a @compileError would require reliable semantic analysis (#552) to avoid emitting incorrect diagnostics. Using the build on save feature of ZLS or vscode-zig can provide these diagnostics.

#1764 does emit tokens with a "deprecated" modifier but it depends on the editor/client on whether they do anything with this information like highlighting the token as strike-through. I've checked VS Code, Sublime Text 4 and Helix but none of them highlighted a symbol as strike-through.

I was able to get symbols highlighted as strike-through in VS Code with the following setting:

"editor.semanticTokenColorCustomizations": {
  "rules": {
    "*.deprecated": {
      "strikethrough": true
    }
  }
},

Not really sure which editor you were using but I am curious to see if your editor is special in that regard or rust_analyzer uses a different approach to get ~~foo~~ as strike-through in rust.

[llogick]

Probably making use of tags?: DiagnosticTag[];, https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#diagnostic

[weskoerber]

Not really sure which editor you were using but I am curious to see if your editor is special in that regard or rust_analyzer uses a different approach to get foo as strike-through in rust.

I'm using neovim (master branch). Neovim's documentation on its diagnostic framework suggests it supports the Deprecated diagnostic tag:

                                                *hl-DiagnosticDeprecated*
DiagnosticDeprecated
    Used for deprecated or obsolete code.

Using the build on save feature of ZLS or vscode-zig can provide these diagnostics.

I was able to get symbols highlighted as strike-through in VS Code with the following setting:

Interesting, I'll test with enable_build_on_save turned on and report back.

Probably making use of tags?: DiagnosticTag[];, https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#diagnostic

That does appear to be the case (using the lsp-types crate). However, I'm not familiar with rust_analyzer from a developer's perspective. I'm just a user. That could be a red herring.

[weskoerber]

Unfortunately, setting enable_build_on_save didn't get deprecation warning diagnostics comparable to rust-analyzer.

If you were able to get it working in VS Code, perhaps this is editor specific?

[weskoerber]

Swinging back around on this... I was able to reproduce your results on Windows using VS Code. This is an editor specific issue. I'm gonna close this, but if I find a way to get it working in Neovim I'll update this issue.

[weskoerber]

So I eventually figured this out, and it was a pretty dumb reason: I wasn't passing the client capabilities to the LSP server. After passing the capabilities to the setup call in my neovim lua, it worked:

require('lspconfig').zls.setup({
  capabilities = client_capabilities,
})