preg_match in match expression - variable might be undefined

[uuf6429]

Bug report

match expressions in PHP can make up as a decent pattern matching engine. Unfortunately it seems to confuse phpstan a bit.

Here are three similar cases, for side-by side comparison:

• https://phpstan.org/r/21bf6895-eca2-4ffe-922e-79bc2f4cf8bc - simple if condition, works 👍
• https://phpstan.org/r/7875af98-f3bc-4489-8694-adb9d2f549fb - using switch statement, also works 👍
• https://phpstan.org/r/577b8c37-acaf-46b1-8413-6b1dcf19b150 - and match statement, doesn't work 👎

Might be related to #7705, not sure.

Code snippet that reproduces the problem

$subject = 'hello world';
$something = match (1) {
    preg_match('/(\d+)/', $subject, $match) => 'it is a number: ' . $match[1],
    preg_match('/(\w+)/', $subject, $match) => 'it is a word: ' . $match[1],
    default => 'it is...something',
};

Actual output

Variable $match might not be defined.

Expected output

phpstan warning was not expected

Did PHPStan help you today? Did it make you happy in any way?

Help - yes - it did catch quite a few non-trivial mistakes.
Happy, not so much - means I need to review my own stuff more often. 🙈 😅

[ondrejmirtes]

Fixed: phpstan/phpstan-src@2b74aa8

[github-actions]

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