[bot]: remove unreferenced code

lib/generators.nix

@@ -19,8 +19,6 @@ let
   libStr = lib.strings;
   libAttr = lib.attrsets;
 
-  flipMapAttrs = flip libAttr.mapAttrs;
-
   inherit (lib) isFunction;
 in
 

lib/lists.nix

@@ -64,7 +64,6 @@ rec {
   */
   foldl = op: nul: list:
     let
-      len = length list;
       foldl' = n:
         if n == -1
         then nul

lib/modules.nix

@@ -670,7 +670,6 @@ rec {
     { config, options, ... }:
     let
       fromOpt = getAttrFromPath from options;
-      toOpt = getAttrFromPath to options;
       toOf = attrByPath to
         (abort "Renaming error: option `${showOption to}' does not exist.");
     in

lib/tests/misc.nix

@@ -380,10 +380,6 @@ runTests {
 
           resRem7 = res6.replace (a: removeAttrs a ["a"]);
 
-          resReplace6 = let x = defaultOverridableDelayableArgs id { a = 7; mergeAttrBy = { a = builtins.add; }; };
-                            x2 = x.merge { a = 20; }; # now we have 27
-                        in (x2.replace) { a = 10; }; # and override the value by 10
-
           # fixed tests (delayed args): (when using them add some comments, please)
           resFixed1 =
                 let x = defaultOverridableDelayableArgs id ( x: { a = 7; c = x.fixed.b; });

lib/types.nix

@@ -309,7 +309,6 @@ rec {
               }
           else
             def;
-        listOnly = listOf elemType;
         attrOnly = attrsOf elemType;
       in mkOptionType rec {
         name = "loaOf";