feat(languages/nix): statix & deadnix diagnostics

docs/release-notes/rl-0.5.adoc

@@ -35,3 +35,5 @@ https://github.com/notashelf[notashelf]:
 * Addeed nvim-navic integration for catppuccin theme
 
 * Fixed mismatching zig language description
+
+* Added support for `statix` and `deadnix` through <<opt-vim.languages.nix.extraDiagnostics.types>>

modules/languages/nix.nix

@@ -82,6 +82,32 @@ with builtins; let
       # Never need to use null-ls for nixpkgs-fmt
     };
   };
+
+  defaultDiagnostics = ["statix" "deadnix"];
+  diagnostics = {
+    statix = {
+      package = pkgs.statix;
+      nullConfig = pkg: ''
+        table.insert(
+          ls_sources,
+          null_ls.builtins.diagnostics.statix.with({
+            command = "${pkg}/bin/statix",
+          })
+        )
+      '';
+    };
+    deadnix = {
+      package = pkgs.deadnix;
+      nullConfig = pkg: ''
+        table.insert(
+          ls_sources,
+          null_ls.builtins.diagnostics.deadnix.with({
+            command = "${pkg}/bin/deadnix",
+          })
+        )
+      '';
+    };
+  };
 in {
   options.vim.languages.nix = {
     enable = mkEnableOption "Nix language support";
@@ -124,6 +150,19 @@ in {
         default = formats.${cfg.format.type}.package;
       };
     };
+
+    extraDiagnostics = {
+      enable = mkOption {
+        description = "Enable extra Nix diagnostics";
+        type = types.bool;
+        default = config.vim.languages.enableExtraDiagnostics;
+      };
+      types = lib.nvim.types.diagnostics {
+        langDesc = "Nix";
+        inherit diagnostics;
+        inherit defaultDiagnostics;
+      };
+    };
   };
 
   config = mkIf cfg.enable (mkMerge [
@@ -147,5 +186,14 @@ in {
       vim.lsp.null-ls.enable = true;
       vim.lsp.null-ls.sources.nix-format = formats.${cfg.format.type}.nullConfig;
     })
+
+    (mkIf cfg.extraDiagnostics.enable {
+      vim.lsp.null-ls.enable = true;
+      vim.lsp.null-ls.sources = lib.nvim.languages.diagnosticsToLua {
+        lang = "nix";
+        config = cfg.extraDiagnostics.types;
+        inherit diagnostics;
+      };
+    })
   ]);
 }