<?php

enum LocaleCode: string
{
    case Dutch = 'nl_NL';
}

#[ORM\Entity, ORM\Table]
class Locale
{
    #[ORM\Id]
    #[ORM\Column(name: 'code', type: Types::STRING, enumType: LocaleCode::class)]
    public LocaleCode $code;
}

#[ORM\Entity, ORM\Table]
class CategoryLocale
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column(name: 'id', type: Types::INTEGER)]
    public int $id;

    #[ORM\ManyToOne(targetEntity: \Entity\Locale::class, cascade: ['persist'])]
    #[ORM\JoinColumn(name: 'locale_code', referencedColumnName: 'code', nullable: false)]
    public Locale $locale;
}

global $entityManager;

// Create entity with BackedEnum as primary key.
$locale = new \Entity\Locale();
$locale->code = \Enum\LocaleCode::Dutch;

// Persist entity, clear manager.
$entityManager->persist($locale);
$entityManager->flush();
$entityManager->clear();

// Create entity with an association to the entity with BackedEnum key.
// Note that the use of a proxy class is required for the error to show.
$categoryLocale = new \Entity\CategoryLocale();
$categoryLocale->locale = $entityManager->getReference(\Entity\Locale::class, \Enum\LocaleCode::Dutch);

// Attempt to persist, throws an error.
$entityManager->persist($categoryLocale);
$entityManager->flush();