title: Declaration of DoctrineORMEntityManager ::initializeProxy() must be compatible with ProxyManager\Proxy\LazyLoadingInterface::initializeProxy(): bool
body: <p>When I type this command 
  <code>php app/console assetic:dump --env=prod --no-debug</code> or this one <code>php app/console cache:clear --env=prod</code></p>
  
  <p>I got the following error :</p>
  
  <pre><code>PHP Fatal error:  Declaration of DoctrineORMEntityManager_0000000035a1d9b70000558a7db0d6e7da5c7b8013722216782206eefb5b6fe5::initializeProxy() must be compatible with ProxyManager\Proxy\LazyLoadingInterface::initializeProxy(): bool in /var/www/myproject/app/cache/prod/appProdProjectContainer.php on line 4459
  </code></pre>
  
  <p>FYI</p>
  
  <pre><code>php --version
  PHP 7.2.28 (cli) (built: Feb 18 2020 11:07:04) ( NTS )
  Copyright (c) 1997-2018 The PHP Group
  Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
  </code></pre>
  
  <p>It used to worked when I used php 5.</p>