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<?php enum TestEnum: string { case X = 'x'; } var_dump(\is_a(TestEnum::class, \StringBackedEnum::class, true)); var_dump(\is_a(TestEnum::class, \BackedEnum::class, true));
Output for 8.1.17 - 8.1.31, 8.2.4 - 8.2.27, 8.3.5 - 8.3.15, 8.4.1 - 8.4.2
bool(false) bool(true)

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