Conflict with nvim-lspconfig v2.1.0

### Neovim version (nvim -v) v0.11.0 ### Operating system/version NixOS 25.05 ### Output of :checkhealth haskell-tools ```console haskell-tools: require("haskell-tools.health").check() Checking for Lua dependencies ~ - ✅ OK [nvim-telescope/telescope.nvim](https://github.com/nvim-telescope/telescope.nvim) installed. Checking external dependencies ~ - ✅ OK haskell-language-server: found nix (Nix) 2.28.2 - ✅ OK hoogle: found Hoogle 5.0.18.4, https://hoogle.haskell.org/ - ✅ OK fast-tags: found fast-tags, version 2.0.2 - ✅ OK curl: found curl 8.12.1 (x86_64-pc-linux-gnu) libcurl/8.12.1 OpenSSL/3.4.1 zlib/1.3.1 brotli/1.1.0 zstd/1.5.7 libidn2/2.3.8 libpsl/0.21.5 libssh2/1.11.1 nghttp2/1.65.0 - ⚠️ WARNING haskell-debug-adapter: not found. Install [haskell-debug-adapter](https://github.com/phoityne/haskell-debug-adapter) for extended capabilities. Optional, for `dap` support. - ⚠️ WARNING ghci-dap: not found. Install [ghci-dap](https://github.com/phoityne/ghci-dap) for extended capabilities. Optional, for `dap` support. Checking config ~ - ✅ OK No errors found in config. Checking for conflicting plugins ~ - ✅ OK No conflicting plugins detected. ``` ### How to reproduce the issue 1) Open a Haskell file. 2) Hit `<leader>f` to format. 3) Run `:LspInfo` ### Expected behaviour Formatted via `fourmolu` respecting the project's `fourmolu.yaml`. This was the behaviour before v5.0.0. Expected no errors from `:LspInfo`. ### Actual behaviour Formatted via some default, presumably `ormolu`. `:LspInfo` produces: ``` ============================================================================== vim.lsp: require("vim.lsp.health").check() - LSP log level : WARN - Log path: /home/burtannia/.local/state/nvim/lsp.log - Log size: 87974 KB vim.lsp: Active Clients ~ - ❌ ERROR Failed to run healthcheck for "vim.lsp" plugin. Exception: Vim:E729: Using a Funcref as a String ``` I believe this is down to `haskell-tools` since running `hls` via `lspconfig` with an identical config works fine: ``` lspconfig.hls.setup({ on_attach = on_attach, cmd = { "nix", "run", ".#hls", "--", "--lsp" }, settings = { haskell = { formattingProvider = "fourmolu", }, }, }) ``` ### Log files ```console ``` ### The minimal config used to reproduce this issue. ```Lua local on_attach = function(_, bufnr) bufmap("<leader>f", function() vim.lsp.buf.format({ async = true }) end) end vim.g.haskell_tools = { hls = { on_attach = on_attach, cmd = { "nix", "run", ".#hls", "--", "--lsp" }, settings = { haskell = { formattingProvider = "fourmolu", }, }, }, } ```