// ...

use Symfony\Component\Security\Core\User\UserInterface;

class User implements UserInterface
{

    // ...
    
    // Ajouter ou modifier les fonctions requises :
    //*********************************************
    
    public function getUsername(): ?string
    {
        return $this->username;
    }
    
    public function eraseCredentials() {
    
    }
 
    public function getSalt() {
    
    }
 
    public function getRoles() {
        $roles = $this->roles;
        // guarantee every user at least has ROLE_USER
        $roles[] = 'ROLE_USER';

        return array_unique($roles);        
    }
    
}