phpstan: False positive always-true with `in_array`

I expect no error from the code https://phpstan.org/r/179a9da2-e9e7-4d4b-b4af-b0e01c35a9db

In my project issue I get

Call to function in_array() with arguments 0, array<int, 0|1>&nonEmpty and true will always evaluate to true.

But even if the array is non-empty, the in_array check isn’t supposed to be always true.

About this issue

Original URL
State: closed
Created 3 years ago
Reactions: 1
Comments: 15 (13 by maintainers)

Commits related to this issue

Regression tests Closes https://github.com/phpstan/phpstan/issues/5759 Closes https://github.com/phpstan/phpstan/issues/5668 Closes https://github.com/phpstan/phpstan/issues/5496 Closes https://githu... — committed to phpstan/phpstan-src by ondrejmirtes 2 years ago

Most upvoted comments

The issue can be simplified to https://phpstan.org/r/02705e4a-3f03-4fa4-83c1-9e1ec86a76f5

leads to $a typed with array<int, 0|1> and thats obviously contains always 0.

array<int, 0|1> doesn’t always contain 0 to me.

[1, 1, 1, 1] or [] are both example which are compatible to the array<int, 0|1> definition to me.

+2

VincentLanglet on Aug 1, 2021

in_array() is a problematic function. Here’s where it’s implemented:

https://github.com/phpstan/phpstan-src/blob/master/src/Type/Php/InArrayFunctionTypeSpecifyingExtension.php
https://github.com/phpstan/phpstan-src/blob/e10a7aac373e8b6f21b430034fc693300c2bbb69/src/Rules/Comparison/ImpossibleCheckTypeHelper.php#L85-L135 (to filter out some situations that should not be reported as “always true” or “always false”

Ideally all of this should be handled in InArrayFunctionTypeSpecifyingExtension. It would also fix https://github.com/phpstan/phpstan-webmozart-assert/issues/142.

+1

ondrejmirtes on Jun 20, 2022

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