made it clear that Twig_Loader_String must not be used by end users

doc/api.rst

@@ -166,21 +166,6 @@ Namespaced templates can be accessed via the special
 
     $twig->render('@admin/index.html', array());
 
-``Twig_Loader_String``
-......................
-
-``Twig_Loader_String`` loads templates from strings. It's a dummy loader as
-the template reference is the template source code::
-
-    $loader = new Twig_Loader_String();
-    $twig = new Twig_Environment($loader);
-
-    echo $twig->render('Hello {{ name }}!', array('name' => 'Fabien'));
-
-This loader should only be used for unit testing as it has severe limitations:
-several tags, like ``extends`` or ``include`` do not make sense to use as the
-reference to the template is the template source code itself.
-
 ``Twig_Loader_Array``
 .....................
 
@@ -268,26 +253,6 @@ All loaders implement the ``Twig_LoaderInterface``::
         function isFresh($name, $time);
     }
 
-As an example, here is how the built-in ``Twig_Loader_String`` reads::
-
-    class Twig_Loader_String implements Twig_LoaderInterface
-    {
-        public function getSource($name)
-        {
-          return $name;
-        }
-
-        public function getCacheKey($name)
-        {
-          return $name;
-        }
-
-        public function isFresh($name, $time)
-        {
-          return false;
-        }
-    }
-
 The ``isFresh()`` method must return ``true`` if the current cached template
 is still fresh, given the last modification time, or ``false`` otherwise.
 

doc/intro.rst

@@ -50,12 +50,14 @@ This section gives you a brief introduction to the PHP API for Twig.
 
     require_once '/path/to/vendor/autoload.php';
 
-    $loader = new Twig_Loader_String();
+    $loader = new Twig_Loader_Array(
+        'index' => 'Hello {{ name }}!',
+    );
     $twig = new Twig_Environment($loader);
 
-    echo $twig->render('Hello {{ name }}!', array('name' => 'Fabien'));
+    echo $twig->render('index', array('name' => 'Fabien'));
 
-Twig uses a loader (``Twig_Loader_String``) to locate templates, and an
+Twig uses a loader (``Twig_Loader_Array``) to locate templates, and an
 environment (``Twig_Environment``) to store the configuration.
 
 The ``render()`` method loads the template passed as a first argument and

lib/Twig/Loader/Array.php

@@ -17,6 +17,8 @@
  * source code of the template). If you don't want to see your cache grows out of
  * control, you need to take care of clearing the old cache file by yourself.
  *
+ * This loader should only be used for unit testing.
+ *
  * @author Fabien Potencier <fabien@symfony.com>
  */
 class Twig_Loader_Array implements Twig_LoaderInterface, Twig_ExistsLoaderInterface

lib/Twig/Loader/String.php

@@ -12,9 +12,7 @@
 /**
  * Loads a template from a string.
  *
- * This loader should only be used for unit testing as it has many limitations
- * (for instance, the include or extends tag does not make any sense for a string
- * loader).
+ * This loader should NEVER be used. It only exists for Twig internal purposes.
  *
  * When using this loader with a cache mechanism, you should know that a new cache
  * key is generated each time a template content "changes" (the cache key being the