<?php declare(strict_types = 1);

function foo(int $value, ?string $suffix): int {
	match ($suffix) {
            'k', 'K' => $pow = 1,
            'm', 'M' => $pow = 2,
            'g', 'G' => $pow = 3,
            default => $pow = 0
	};
	return $value * (1024 ** $pow); // False positive error: Variable $pow might not be defined.
}

$pow = match ($suffix) {
    'k', 'K' => 1,
    'm', 'M' => 2,
    'g', 'G' => 3,
    default => 0
};