Unset on a list should report an error

[ondrejmirtes]

Feature request

https://phpstan.org/r/31b7e82b-cbdf-4241-903a-11c2c92bebaf

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

No response

[mad-briller]

if the last element in the list is unset that would still preserve the list type is, is it worth taking that into account?

[ondrejmirtes]

I don't think it remains a list. It also depends what happens when you append a new value after the unset using $a[] = 1.

[mad-briller]

wow you are correct, you never stop learning weird aspects of php:

https://3v4l.org/leF25

[ondrejmirtes]

Implemented phpstan/phpstan-src@aeadbe2

[staabm]

should we get the same error in this situation?

https://phpstan.org/r/d7ff4b4a-3972-4b58-ac4d-75baa331b03a

[staabm]

ohh I got it now. the actual errors happens when we write the "no longer list" back into a variable/property which expects a list.

the unset() itself is not the error. in my example it works by removing the list type from the variable involved
https://phpstan.org/r/a0182412-9c37-4195-9a96-4d280fa965e1

[ondrejmirtes]

Yes 😊 btw you can get the error now with by-ref parameter: https://phpstan.org/r/af367901-7930-4a8b-9bcd-42156f7a2860

[github-actions]

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