From 2e02f73bf71aa7c93c3519cb8723745533dd25d8 Mon Sep 17 00:00:00 2001
From: Hugo Hamon <hugo.hamon@sensiolabs.com>
Date: Sat, 23 Apr 2016 16:01:10 +0200
Subject: [PATCH] [ExpressionParser] forbids true, false, null and none
 keywords for variables names.

---
 lib/Twig/ExpressionParser.php            | 7 ++++---
 test/Twig/Tests/ExpressionParserTest.php | 5 +++++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/Twig/ExpressionParser.php b/lib/Twig/ExpressionParser.php
index 7b2d58f27..ec85a4dbc 100644
--- a/lib/Twig/ExpressionParser.php
+++ b/lib/Twig/ExpressionParser.php
@@ -539,10 +539,11 @@ class Twig_ExpressionParser
         $targets = array();
         while (true) {
             $token = $this->parser->getStream()->expect(Twig_Token::NAME_TYPE, null, 'Only variables can be assigned to');
-            if (in_array($token->getValue(), array('true', 'false', 'none'))) {
-                throw new Twig_Error_Syntax(sprintf('You cannot assign a value to "%s".', $token->getValue()), $token->getLine(), $this->parser->getFilename());
+            $value = $token->getValue();
+            if (in_array(strtolower($value), array('true', 'false', 'none', 'null'))) {
+                throw new Twig_Error_Syntax(sprintf('You cannot assign a value to "%s"', $value), $token->getLine(), $this->parser->getFilename());
             }
-            $targets[] = new Twig_Node_Expression_AssignName($token->getValue(), $token->getLine());
+            $targets[] = new Twig_Node_Expression_AssignName($value, $token->getLine());
 
             if (!$this->parser->getStream()->nextIf(Twig_Token::PUNCTUATION_TYPE, ',')) {
                 break;
diff --git a/test/Twig/Tests/ExpressionParserTest.php b/test/Twig/Tests/ExpressionParserTest.php
index 33bf48be7..fdab7e7b0 100644
--- a/test/Twig/Tests/ExpressionParserTest.php
+++ b/test/Twig/Tests/ExpressionParserTest.php
@@ -27,8 +27,13 @@ class Twig_Tests_ExpressionParserTest extends PHPUnit_Framework_TestCase
     {
         return array(
             array('{% set false = "foo" %}'),
+            array('{% set FALSE = "foo" %}'),
             array('{% set true = "foo" %}'),
+            array('{% set TRUE = "foo" %}'),
             array('{% set none = "foo" %}'),
+            array('{% set NONE = "foo" %}'),
+            array('{% set null = "foo" %}'),
+            array('{% set NULL = "foo" %}'),
             array('{% set 3 = "foo" %}'),
             array('{% set 1 + 2 = "foo" %}'),
             array('{% set "bar" = "foo" %}'),