lib/options (mkSettingsOption): allow more types for settingsOption when no sub-options are explicitly declared

lib/options.nix

@@ -329,14 +329,22 @@ rec {
       options ? { },
       description,
       example ? null,
+      # If no sub-options are explicitly declared, settings do not need to be a submodule.
+      submoduleType ? options != { },
     }:
     lib.mkOption {
       type =
-        with types;
+        let
-        submodule {
+          anyLuaType = lib.nixvim.lua-types.anything;
-          freeformType = attrsOf lib.nixvim.lua-types.anything;
+        in
-          inherit options;
+        if submoduleType then
-        };
+          types.submodule {
+            freeformType = types.attrsOf anyLuaType;
+            inherit options;
+          }
+        else
+          assert options == { };
+          anyLuaType;
       default = { };
       inherit description;
       example =

plugins/lsp/language-servers/_mk-lsp.nix

@@ -179,6 +179,12 @@ in
       settings = lib.nixvim.mkSettingsOption {
         description = "The settings for this LSP.";
         options = settingsOptions;
+
+        # Some servers declare settings sub-options without using `settingsOptions`.
+        # This leads the `settings` option to not be typed as a submodule.
+        # Hence, we force all `plugins.lsp.<name>.settings` options to be types as submodules.
+        # FIXME This is not ideal, but `plugins.lsp` will be dropped entirely in a few months.
+        submoduleType = true;
       };
 
       extraOptions = mkOption {