1 files changed, 90 insertions, 0 deletions
diff --git a/nvim/lua/plugins/rust.lua b/nvim/lua/plugins/rust.lua
new file mode 100644
index 0000000..8813700
--- /dev/null
+++ b/nvim/lua/plugins/rust.lua
@@ -0,0 +1,90 @@
+-- rustaceanvim / rust-analyzer, matched to the VSCodium setup in ../../vscode/settings.json:
+-- clippy instead of cargo check, rustfmt on save, source.fixAll on save, hard tabs.
+--
+-- Drop at: ~/.config/nvim/lua/plugins/rust.lua, and delete the rustaceanvim block
+-- from lua/plugins/init.lua — two lazy.nvim specs for the same plugin will fight.
+
+local timeout_ms = 2000
+
+-- Equivalent of VS Code's "editor.codeActionsOnSave": { "source.fixAll.rust-analyzer" }.
+--
+-- vim.lsp.buf.code_action{apply=true} is asynchronous, so from a BufWritePre autocmd
+-- the buffer is usually written before the edit arrives. buf_request_sync blocks,
+-- which is what makes this actually run before the write.
+--
+-- Same caveat as in VS Code: this applies rust-analyzer's own fixes only. Lints that
+-- come from cargo check or clippy are not included — those still need `cargo fix` or
+-- `cargo clippy --fix` on the command line.
+local function apply_fix_all(bufnr)
+	local client = vim.lsp.get_clients({ bufnr = bufnr, name = "rust-analyzer" })[1]
+	if not client then
+		return
+	end
+
+	local params = vim.lsp.util.make_range_params(0, client.offset_encoding)
+	params.context = { only = { "source.fixAll" }, diagnostics = {} }
+
+	local responses = vim.lsp.buf_request_sync(bufnr, "textDocument/codeAction", params, timeout_ms)
+	if not responses then
+		return
+	end
+
+	for _, response in pairs(responses) do
+		for _, action in ipairs(response.result or {}) do
+			-- A server may return the action unresolved, carrying only `data`;
+			-- the edit then has to be fetched with a second request.
+			if not action.edit and action.data then
+				local resolved =
+					client:request_sync("codeAction/resolve", action, timeout_ms, bufnr)
+				action = (resolved and resolved.result) or action
+			end
+			if action.edit then
+				vim.lsp.util.apply_workspace_edit(action.edit, client.offset_encoding)
+			end
+		end
+	end
+end
+
+vim.api.nvim_create_autocmd("BufWritePre", {
+	group = vim.api.nvim_create_augroup("rust_on_save", { clear = true }),
+	pattern = "*.rs",
+	callback = function(args)
+		apply_fix_all(args.buf)
+		-- VS Code's "editor.formatOnSave" for [rust]: rustfmt, driven by rust-analyzer.
+		vim.lsp.buf.format({
+			bufnr = args.buf,
+			timeout_ms = timeout_ms,
+			filter = function(client)
+				return client.name == "rust-analyzer"
+			end,
+		})
+	end,
+})
+
+return {
+	{
+		"mrcjkb/rustaceanvim",
+		version = "^6",
+		-- No `ft = { "rust" }` here. It is dead weight next to lazy = false, and
+		-- rustaceanvim's own docs advise against lazy-loading it by filetype:
+		-- it installs the FileType handler that starts the LSP itself.
+		lazy = false,
+		config = function()
+			vim.g.rustaceanvim = {
+				server = {
+					on_attach = function(client, bufnr)
+						require("nvchad.configs.lspconfig").on_attach(client, bufnr)
+					end,
+					default_settings = {
+						["rust-analyzer"] = {
+							cargo = { allFeatures = true },
+							checkOnSave = true,
+							-- Matches "rust-analyzer.check.command": "clippy".
+							check = { command = "clippy" },
+						},
+					},
+				},
+			}
+		end,
+	},
+}