False positives for unreachable detection of nested optional elements in an array

[zonuexe]

Bug report

The following code is detected in the latest PHPStan as “Unreachable statement - code above always terminates.”

Maybe MutatingScope::resolveType() needs to recursively inspect the parent element.

Code snippet that reproduces the problem

<?php declare(strict_types = 1);

/**
 * @param array{a?:array{b:bool}} $options
 */
function f(array $options): bool
{
    if (isset($options['a']['b'])) {
        return true;
    }
	
    return false;
}

var_dump(f([])); // returns false

https://phpstan.org/r/c877f393-c5d5-4b81-9655-709ba6b6a85b

Expected output

The last statement is reachable at run time, so no message should be printed.

https://3v4l.org/fjfml

[phpstan-bot]

@zonuexe After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-12: Unreachable statement - code above always terminates.
+ 6: Function f() should return bool but return statement is missing.
+19: Function g() should return bool but return statement is missing.

Full report

Line	Error
6	Function f() should return bool but return statement is missing.
19	Function g() should return bool but return statement is missing.

[ondrejmirtes]

Fixed: phpstan/phpstan-src@3b17acc

[zonuexe]

Great! Thank you!

[github-actions]

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