lib/modules: Fix meta duplication in shorthand syntax

lib/modules.nix

@@ -440,13 +440,14 @@ rec {
           config = addFreeformType (addMeta (m.config or {}));
         }
     else
+      # shorthand syntax
       lib.throwIfNot (isAttrs m) "module ${file} (${key}) does not look like a module."
       { _file = toString m._file or file;
         key = toString m.key or key;
         disabledModules = m.disabledModules or [];
         imports = m.require or [] ++ m.imports or [];
         options = {};
-        config = addFreeformType (addMeta (removeAttrs m ["_file" "key" "disabledModules" "require" "imports" "freeformType"]));
+        config = addFreeformType (removeAttrs m ["_file" "key" "disabledModules" "require" "imports" "freeformType"]);
       };
 
   applyModuleArgsIfFunction = key: f: args@{ config, options, lib, ... }: if isFunction f then

lib/tests/modules.sh

@@ -58,6 +58,9 @@ checkConfigError() {
     fi
 }
 
+# Shorthand meta attribute does not duplicate the config
+checkConfigOutput '^"one two"$' config.result ./shorthand-meta.nix
+
 # Check boolean option.
 checkConfigOutput '^false$' config.enable ./declare-enable.nix
 checkConfigError 'The option .* does not exist. Definition values:\n\s*- In .*: true' config.enable ./define-enable.nix

lib/tests/modules/shorthand-meta.nix

@@ -0,0 +1,19 @@
+{ lib, ... }:
+let
+  inherit (lib) types mkOption;
+in
+{
+  imports = [
+    ({ config, ... }: {
+      options = {
+        meta.foo = mkOption {
+          type = types.listOf types.str;
+        };
+        result = mkOption { default = lib.concatStringsSep " " config.meta.foo; };
+      };
+    })
+    {
+      meta.foo = [ "one" "two" ];
+    }
+  ];
+}