From 5835c2344f8570df573f8ba68929f8fa95422a58 Mon Sep 17 00:00:00 2001
From: Fabien Potencier <fabien@potencier.org>
Date: Mon, 3 Jun 2019 11:44:35 +0200
Subject: [PATCH] allowed string operators as variables names in assignments

---
 CHANGELOG                                      |  2 +-
 src/ExpressionParser.php                       |  8 +++++++-
 .../string_operator_as_var_assignment.test     | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 test/Twig/Tests/Fixtures/expressions/string_operator_as_var_assignment.test

diff --git a/CHANGELOG b/CHANGELOG
index ef867b6411..cbe48fa0c7 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,6 @@
 * 1.42.1 (2019-XX-XX)
 
- * n/a
+ * allowed string operators as variables names in assignments
 
 * 1.42.0 (2019-05-31)
 
diff --git a/src/ExpressionParser.php b/src/ExpressionParser.php
index d19cb58a5c..9066ade169 100644
--- a/src/ExpressionParser.php
+++ b/src/ExpressionParser.php
@@ -649,7 +649,13 @@ public function parseAssignmentExpression()
         $stream = $this->parser->getStream();
         $targets = [];
         while (true) {
-            $token = $stream->expect(Token::NAME_TYPE, null, 'Only variables can be assigned to');
+            $token = $this->parser->getCurrentToken();
+            if ($stream->test(Token::OPERATOR_TYPE) && preg_match(Lexer::REGEX_NAME, $token->getValue())) {
+                // in this context, string operators are variable names
+                $this->parser->getStream()->next();
+            } else {
+                $stream->expect(Token::NAME_TYPE, null, 'Only variables can be assigned to');
+            }
             $value = $token->getValue();
             if (\in_array(strtolower($value), ['true', 'false', 'none', 'null'])) {
                 throw new SyntaxError(sprintf('You cannot assign a value to "%s".', $value), $token->getLine(), $stream->getSourceContext());
diff --git a/test/Twig/Tests/Fixtures/expressions/string_operator_as_var_assignment.test b/test/Twig/Tests/Fixtures/expressions/string_operator_as_var_assignment.test
new file mode 100644
index 0000000000..478d4eb5e5
--- /dev/null
+++ b/test/Twig/Tests/Fixtures/expressions/string_operator_as_var_assignment.test
@@ -0,0 +1,18 @@
+--TEST--
+Twig supports the string operators as variable names in assignments
+--TEMPLATE--
+{% for matches in [1, 2] %}
+    {{- matches }}
+{% endfor %}
+
+{% set matches = [1, 2] %}
+
+OK
+--DATA--
+return []
+--EXPECT--
+1
+2
+
+
+OK