completion snippets behave badly in the presence of combining diacritics

[expipiplus1]

Your environment

Which LSP client (editor/plugin) do you use? Neovim, astrovim (which I think is using luasnips and nvim-cmp)

The actual crash is in nvim-cmp, so it's quite possibly a bug there, but at least turning off plugin.ghcide-completions.config.snippetsOn seems to fix things, so opening this issue just in case anyone else searches combining diacritics snippets or something.

Sorry for the low quality report!

Which version of HLS do you use and how did you install it? haskell-language-server version: 2.9.0.0 (GHC: 9.8.2)

Steps to reproduce

• Set up astrovim and enable the haskell community pack (definitely a smaller repro)
• Open a haskell file
• wait for hls to init
• type â (a with a combining circumflex)
• observe something like:

Error executing vim.schedule lua callback: ...l/share/astrovim/lazy/nvim-cmp/lua/cmp/utils/snippet.lua:409: snippet parsing failed.
stack traceback:
        [C]: in function 'error'
        ...l/share/astrovim/lazy/nvim-cmp/lua/cmp/utils/snippet.lua:409: in function 'parse'
        .../e/.local/share/astrovim/lazy/nvim-cmp/lua/cmp/entry.lua:130: in function 'callback'
        ...cal/share/astrovim/lazy/nvim-cmp/lua/cmp/utils/cache.lua:38: in function 'get_word'
        .../e/.local/share/astrovim/lazy/nvim-cmp/lua/cmp/entry.lua:81: in function 'callback'
        ...cal/share/astrovim/lazy/nvim-cmp/lua/cmp/utils/cache.lua:38: in function 'get_offset'
        ...e/.local/share/astrovim/lazy/nvim-cmp/lua/cmp/source.lua:353: in function ''
        vim/_editor.lua: in function <vim/_editor.lua:0>

[michaelpj]

Certainly there's a client bug there, but if you can check the snippet that gets sent to the client and see if it has anything wrong with it, that would be helpful.

[expipiplus1]

Happy to look at that, but how might I do that?

[fendor]

Presumably, you want to interject the LSP message sent between the client and the server. I don't know how to do this in neovim, but in VSCode, you can set the option haskell.trace.server and set it to verbose. Then the usual Output pane contains the LSP messages, and you can see exactly what is sent by the server.