diff --git a/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php b/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
index 75502db0e9..95f44c86c7 100644
--- a/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
+++ b/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
@@ -146,7 +146,7 @@ class NumberToLocalizedStringTransformer implements DataTransformerInterface
             return;
         }
 
-        if ('NaN' === $value) {
+        if (\in_array($value, array('NaN', 'NAN', 'nan'), true)) {
             throw new TransformationFailedException('"NaN" is not a valid number');
         }
 
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
index d6a4662102..176d3a9a58 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
@@ -514,24 +514,24 @@ class NumberToLocalizedStringTransformerTest extends TestCase
 
     /**
      * @expectedException \Symfony\Component\Form\Exception\TransformationFailedException
+     * @dataProvider nanRepresentationProvider
      *
      * @see https://github.com/symfony/symfony/issues/3161
      */
-    public function testReverseTransformDisallowsNaN()
+    public function testReverseTransformDisallowsNaN($nan)
     {
         $transformer = new NumberToLocalizedStringTransformer();
 
-        $transformer->reverseTransform('NaN');
+        $transformer->reverseTransform($nan);
     }
 
-    /**
-     * @expectedException \Symfony\Component\Form\Exception\TransformationFailedException
-     */
-    public function testReverseTransformDisallowsNaN2()
+    public function nanRepresentationProvider()
     {
-        $transformer = new NumberToLocalizedStringTransformer();
-
-        $transformer->reverseTransform('nan');
+        return array(
+            array('nan'),
+            array('NaN'), // see https://github.com/symfony/symfony/issues/3161
+            array('NAN'),
+        );
     }
 
     /**
diff --git a/src/Symfony/Component/Validator/Context/ExecutionContextInterface.php b/src/Symfony/Component/Validator/Context/ExecutionContextInterface.php
index 544c82f6c0..e4f7df1757 100644
--- a/src/Symfony/Component/Validator/Context/ExecutionContextInterface.php
+++ b/src/Symfony/Component/Validator/Context/ExecutionContextInterface.php
@@ -112,7 +112,7 @@ interface ExecutionContextInterface
      * Returns the currently validated object.
      *
      * If the validator is currently validating a class constraint, the
-     * object of that class is returned. If it is a validating a property or
+     * object of that class is returned. If it is validating a property or
      * getter constraint, the object that the property/getter belongs to is
      * returned.
      *