diff --git a/includes/menu.inc b/includes/menu.inc
index 2cd620770b2ab45c044f52a016add9af7000fb65..bba9391ffe0e2257141ebf36898905c594968de3 100644
--- a/includes/menu.inc
+++ b/includes/menu.inc
@@ -1220,17 +1220,16 @@ function menu_get_active_help() {
   $arg = drupal_help_arg(arg(NULL));
   $empty_arg = drupal_help_arg();
 
-  foreach (module_list() as $name) {
-    if (module_hook($name, 'help')) {
-      // Lookup help for this path.
-      if ($help = module_invoke($name, 'help', $router_path, $arg)) {
-        $output .= $help . "\n";
-      }
-      // Add "more help" link on admin pages if the module provides a
-      // standalone help page.
-      if ($arg[0] == "admin" && module_exists('help') && module_invoke($name, 'help', 'admin/help#' . $arg[2], $empty_arg) && $help) {
-        $output .= theme("more_help_link", url('admin/help/' . $arg[2]));
-      }
+  foreach (module_implements('help') as $module) {
+    $function = $module . '_help';
+    // Lookup help for this path.
+    if ($help = $function($router_path, $arg)) {
+      $output .= $help . "\n";
+    }
+    // Add "more help" link on admin pages if the module provides a
+    // standalone help page.
+    if ($arg[0] == "admin" && module_exists('help') && $function('admin/help#' . $arg[2], $empty_arg) && $help) {
+      $output .= theme("more_help_link", url('admin/help/' . $arg[2]));
     }
   }
   return $output;
diff --git a/modules/comment/comment.module b/modules/comment/comment.module
index 055e30f92ceecd100a1cb4eb0e908c42777fd4e2..c8573d7c021680c4b39dd367214fca5b57d4c9a5 100644
--- a/modules/comment/comment.module
+++ b/modules/comment/comment.module
@@ -1945,8 +1945,8 @@ function _comment_update_node_statistics($nid) {
  */
 function comment_invoke_comment(&$comment, $op) {
   $return = array();
-  foreach (module_implements('comment') as $name) {
-    $function = $name . '_comment';
+  foreach (module_implements('comment') as $module) {
+    $function = $module . '_comment';
     $result = $function($comment, $op);
     if (isset($result) && is_array($result)) {
       $return = array_merge($return, $result);
diff --git a/modules/filter/filter.module b/modules/filter/filter.module
index e2e2a20f120aa6f0aa21e95a2261bfbcfd4dfb97..f77f5399c987253dd6347984ecebd471f6d754c3 100644
--- a/modules/filter/filter.module
+++ b/modules/filter/filter.module
@@ -326,8 +326,9 @@ function filter_formats($index = NULL) {
 function filter_list_all() {
   $filters = array();
 
-  foreach (module_list() as $module) {
-    $list = module_invoke($module, 'filter', 'list');
+  foreach (module_implements('filter') as $module) {
+    $function = $module . '_filter';
+    $list = $function('list');
     if (isset($list) && is_array($list)) {
       foreach ($list as $delta => $name) {
         $filters[$module . '/' . $delta] = (object)array('module' => $module, 'delta' => $delta, 'name' => $name);
diff --git a/modules/node/node.module b/modules/node/node.module
index 8c8ecd48aea9e53ce886aa45c4db52fdca9c6ea5..b64dbdebf450ff0bfb558e3c7694216eae01646a 100644
--- a/modules/node/node.module
+++ b/modules/node/node.module
@@ -716,8 +716,8 @@ function node_invoke(&$node, $hook, $a2 = NULL, $a3 = NULL, $a4 = NULL) {
 function node_invoke_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
   $return = array();
   $hook = 'nodeapi_' . $op;
-  foreach (module_implements($hook) as $name) {
-    $function = $name . '_' . $hook;
+  foreach (module_implements($hook) as $module) {
+    $function = $module . '_' . $hook;
     $result = $function($node, $a3, $a4);
     if (isset($result) && is_array($result)) {
       $return = array_merge($return, $result);
diff --git a/modules/search/search.admin.inc b/modules/search/search.admin.inc
index f02ce7dfc677418aafb0abe5b8ffe64765bb1f53..c1a8eb0efdb8f830242e3c975ba17ae026ca2b85 100644
--- a/modules/search/search.admin.inc
+++ b/modules/search/search.admin.inc
@@ -37,12 +37,11 @@ function search_admin_settings() {
   // Collect some stats
   $remaining = 0;
   $total = 0;
-  foreach (module_list() as $module) {
-    if (module_hook($module, 'search')) {
-      $status = module_invoke($module, 'search', 'status');
-      $remaining += $status['remaining'];
-      $total += $status['total'];
-    }
+  foreach (module_implements('search') as $module) {
+    $function = $module . '_search';
+    $status = $function('status');
+    $remaining += $status['remaining'];
+    $total += $status['total'];
   }
   $count = format_plural($remaining, 'There is 1 item left to index.', 'There are @count items left to index.');
   $percentage = ((int)min(100, 100 * ($total - $remaining) / max(1, $total))) . '%';
diff --git a/modules/search/search.module b/modules/search/search.module
index 924795dd3c5eae986b559479e2f148e827348cb1..7972549821ace6f7a4dcd72d6a6f29159edf1a19 100644
--- a/modules/search/search.module
+++ b/modules/search/search.module
@@ -208,14 +208,14 @@ function search_menu() {
     'file path' => drupal_get_path('module', 'dblog'),
   );
 
-  foreach (module_implements('search') as $name) {
-    $items['search/' . $name . '/%menu_tail'] = array(
+  foreach (module_implements('search') as $module) {
+    $items['search/' . $module . '/%menu_tail'] = array(
       'title callback' => 'module_invoke',
-      'title arguments' => array($name, 'search', 'name', TRUE),
+      'title arguments' => array($module, 'search', 'name', TRUE),
       'page callback' => 'search_view',
-      'page arguments' => array($name),
+      'page arguments' => array($module),
       'access callback' => '_search_menu',
-      'access arguments' => array($name),
+      'access arguments' => array($module),
       'type' => MENU_LOCAL_TASK,
       'parent' => 'search',
     );
@@ -277,8 +277,9 @@ function search_cron() {
   register_shutdown_function('search_update_totals');
 
   // Update word index
-  foreach (module_list() as $module) {
-    module_invoke($module, 'update_index');
+  foreach (module_implements('update_index') as $module) {
+    $function = $module . '_update_index';
+    $function();
   }
 }
 
diff --git a/modules/user/user.module b/modules/user/user.module
index 224d44d419eb785ef82079794c582311daa6c70a..f1a8593b7985355e8d011a38930424e0a46d0c6e 100644
--- a/modules/user/user.module
+++ b/modules/user/user.module
@@ -23,11 +23,9 @@
  * be passed by reference.
  */
 function user_module_invoke($type, &$array, &$user, $category = NULL) {
-  foreach (module_list() as $module) {
+  foreach (module_implements('user_' . $type) as $module) {
     $function = $module . '_user_' . $type;
-    if (function_exists($function)) {
-      $function($array, $user, $category);
-    }
+    $function($array, $user, $category);
   }
 }
 
@@ -1952,8 +1950,9 @@ function user_filters() {
   }
 
   $options = array();
-  foreach (module_list() as $module) {
-    if ($permissions = module_invoke($module, 'perm')) {
+  foreach (module_implements('perm') as $module) {
+    $function = $module . '_perm';
+    if ($permissions = $function('perm')) {
       asort($permissions);
       foreach ($permissions as $permission => $description) {
         $options[t('@module module', array('@module' => $module))][$permission] = t($permission);
@@ -2437,8 +2436,9 @@ function user_register_validate($form, &$form_state) {
  */
 function _user_forms(&$edit, $account, $category, $hook = 'form') {
   $groups = array();
-  foreach (module_list() as $module) {
-    if ($data = module_invoke($module, 'user_' . $hook, $edit, $account, $category)) {
+  foreach (module_implements('user_' . $hook) as $module) {
+    $function = $module . '_user_' . $hook;
+    if ($data = $function($edit, $account, $category)) {
       $groups = array_merge_recursive($data, $groups);
     }
   }