Fix Cache error while using anonymous class

src/Symfony/Component/Validator/Mapping/Cache/Psr6Cache.php

@@ -70,6 +70,11 @@ class Psr6Cache implements CacheInterface
      */
     private function escapeClassName($class)
     {
+        if (false !== strpos($class, '@')) {
+            // anonymous class: replace all PSR6-reserved characters
+            return str_replace(["\0", '\\', '/', '@', ':', '{', '}', '(', ')'], '.', $class);
+        }
+
         return str_replace('\\', '.', $class);
     }
 }

src/Symfony/Component/Validator/Tests/Mapping/Cache/Psr6CacheTest.php

@@ -23,4 +23,12 @@ class Psr6CacheTest extends AbstractCacheTest
         $this->cache->write($metadata);
         $this->assertFalse($this->cache->has('Foo_Bar'));
     }
+
+    public function testNameWithInvalidChars()
+    {
+        $metadata = new ClassMetadata('class@anonymous/path/file');
+
+        $this->cache->write($metadata);
+        $this->assertTrue($this->cache->has('class@anonymous/path/file'));
+    }
 }