diff --git a/includes/menu.inc b/includes/menu.inc
index 39f7dddade90d115d9f7b35f58b848cf41d7f9db..8c2255067fb7b86c24179b448799843adae90cd7 100644
--- a/includes/menu.inc
+++ b/includes/menu.inc
@@ -3166,12 +3166,15 @@ function _menu_router_build($callbacks) {
           if (!isset($item['page arguments']) && isset($parent['page arguments'])) {
             $item['page arguments'] = $parent['page arguments'];
           }
-          if (!isset($item['file']) && isset($parent['file'])) {
-            $item['file'] = $parent['file'];
-          }
           if (!isset($item['file path']) && isset($parent['file path'])) {
             $item['file path'] = $parent['file path'];
           }
+          if (!isset($item['file']) && isset($parent['file'])) {
+            $item['file'] = $parent['file'];
+            if (empty($item['file path']) && isset($item['module']) && isset($parent['module']) && $item['module'] != $parent['module']) {
+              $item['file path'] = drupal_get_path('module', $parent['module']);
+            }
+          }
         }
         // Same for delivery callbacks.
         if (!isset($item['delivery callback']) && isset($parent['delivery callback'])) {
diff --git a/modules/simpletest/tests/menu.test b/modules/simpletest/tests/menu.test
index d9563a86a196a3613e50b8e4ff2e078c76354244..0e6da766b1b1bb8b185aa991797a08da632ec8fa 100644
--- a/modules/simpletest/tests/menu.test
+++ b/modules/simpletest/tests/menu.test
@@ -51,6 +51,15 @@ class MenuRouterTestCase extends DrupalWebTestCase {
     $this->assertRaw('seven/style.css', t("The administrative theme's CSS appears on the page."));
   }
 
+  /**
+   * Test that 'page callback', 'file' and 'file path' keys are properly
+   * inherited from parent menu paths.
+   */
+  function testFileInheritance() {
+    $this->drupalGet('admin/config/development/file-inheritance');
+    $this->assertText('File inheritance test description', t('File inheritance works.'));
+  }
+
   /**
    * Test path containing "exotic" characters.
    */
diff --git a/modules/simpletest/tests/menu_test.module b/modules/simpletest/tests/menu_test.module
index 1e436ee59a9859b25620e33729768cd46c0a1b1d..ee8f2ea1b7cb42ac8e4f0b297ef1e3bead4724fd 100644
--- a/modules/simpletest/tests/menu_test.module
+++ b/modules/simpletest/tests/menu_test.module
@@ -173,6 +173,22 @@ function menu_test_menu() {
     'context' => MENU_CONTEXT_NONE,
   );
 
+  // File inheritance tests. This menu item should inherit the page callback
+  // system_admin_menu_block_page() and therefore render its children as links
+  // on the page.
+  $items['admin/config/development/file-inheritance'] = array(
+    'title' => 'File inheritance',
+    'description' => 'Test file inheritance',
+    'access arguments' => array('access content'),
+  );
+  $items['admin/config/development/file-inheritance/inherit'] = array(
+    'title' => 'Inherit',
+    'description' => 'File inheritance test description',
+    'page callback' => 'menu_test_callback',
+    'access arguments' => array('access content'),
+    'type' => MENU_LOCAL_TASK,
+  );
+
   return $items;
 }