bug symfony#34163 [DI] fix regexp for anonymous services with no clas…

…s set (nicolas-grekas)

This PR was merged into the 4.4 branch.

Discussion
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[DI] fix regexp for anonymous services with no class set

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Follows symfony#33782

Commits
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a302d20 [DI] fix regexp for anonymous services with no class set

src/Symfony/Component/DependencyInjection/Loader/FileLoader.php

@@ -26,7 +26,7 @@
  */
 abstract class FileLoader extends BaseFileLoader
 {
-    public const ANONYMOUS_ID_REGEXP = '/^\.\d+_[^~]++~[._a-zA-Z\d]{7}$/';
+    public const ANONYMOUS_ID_REGEXP = '/^\.\d+_[^~]*+~[._a-zA-Z\d]{7}$/';
 
     protected $container;
     protected $isLoadingInstanceof = false;