Env var maps to undefined constant.

When I try to use a constant as an environment variable, as described in the blog item, 
I run into the following problem.

Env var "SOME_CONST" maps to undefined constant "App\\Util\\SomeClass::SOME_CONST".

The proposed solution works for me, however, I'm not sure if this is the best and conform Symfony standards.

Blog:
https://symfony.com/blog/new-in-symfony-3-4-advanced-environment-variables

Author: dsmink

src/Symfony/Component/DependencyInjection/EnvVarProcessor.php

@@ -110,11 +110,13 @@ public function getEnv($prefix, $name, \Closure $getEnv)
         }
 
         if ('const' === $prefix) {
+            $env = \str_replace("\\\\","\\", $env);
+            
             if (!defined($env)) {
                 throw new RuntimeException(sprintf('Env var "%s" maps to undefined constant "%s".', $name, $env));
             }
 
-            return constant($name);
+            return constant($env);
         }
 
         if ('base64' === $prefix) {