<?php declare(strict_types = 1);

enum X: string {
	case A = 'a';
	case B = 'b';
	case C = 'c';

	/** @return ($this is self::A ? int : null) */
	public function get(): ?int {
		return ($this === self::A) ? null : 123;
	}

	public function doSomething(): void {
		if ($this !== self::A) {
			\PHPStan\dumpType($this); // $this(X~X::A)
			\PHPStan\dumpType($this->get()); // int|null
		}
	}

	public static function doSomethingFor(X $x): void {
		if ($x !== self::A) {
			\PHPStan\dumpType($x); // X~X::A
			\PHPStan\dumpType($x->get()); // int
		}
	}
}