False only boolean type gets lost through a method with a template

[mitelg]

Bug report

Hello there 👋

We have a method that gets all kind of values, and in it an event is dispatched. The return value is the same as the given parameter. It works totally fine, but with one exception, if the passed value is type of array|false. The return type is then array|bool which is not correct. See the prepared example

Code snippet that reproduces the problem

https://phpstan.org/r/a057351b-dec7-449b-b8fb-86e921e2cac6

Expected output

No issue should appear

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We are using PHPStan on a heavy legacy code base and with its help, the code gets more stable every day, thanks for that!

[ondrejmirtes]

This is a hard problem. PHPStan chooses to generalize scalar values so when you pass 1, you get int etc. If you specify scalar bounds, the literal type is preserved: @template TValue of bool

[ondrejmirtes]

Leaving this open as it should also work if you use of array|bool, but it currently doesn't. https://phpstan.org/r/ec06b040-0a8f-4ff3-a3e9-07998024a0ab

[ZebulanStanphill]

For reference, TypeScript handles this properly:

https://www.typescriptlang.org/play?#code/MYGwhgzhAEASCmIQHsDqyBOIAm0DeAsAFDTQRgCeCSyAFAJQBc0ASvMJtgDwQAuGASwB2AcwA00IQFcAtgCN4GAHwAfAGZgQEePmKlSHIX2i94xgLwmAFgIgA6EfF4AVM7wZ79GJ1IxDrtnZqAiCmGACiAG7wQu4A5ORUiChxEqZ89J4AvsSewaGKUTG8XM5KtPDRsQByYDLwzHyCohKRmlIN0M5MXbok+gD0A9DYyNCVxZ6k3ry+-m0gHdm5-Y4ubgzMbBwY3E3C4pKyCsrqmtp9+tCGxhohvjqWALJgvFZ2GGBCozIM0EqWAAMdgArNAAPwmDAdaDMDRaeBTaACNTQWh3RbeaDmHFQjr0S5XaAzObQeHaJE5frTHx+fBqZDIZgARgATABmKmkKlU4g3XjQKwAd2xkngIuoKHQWGwHiIxCG0HCGAwmHGAA8AA7sUy4XhjBTE+CazC6wWKeB2YgotHCoIhMJFWK0OJycBWVJ4+AEnGWcnewk3ZAgS0oEQuqzwChxTJELJAA

[Seldaek]

Just another example as I found this issue when trying to report the same :)

https://phpstan.org/r/6dec0406-f803-4e29-8d21-fd5f631efb94

Found via composer/composer#10429 (comment) (for my future reference if this gets fixed..)

[ondrejmirtes]

Last night I came up with the idea that we mostly shouldn't generalize the generic type variables, except when they're in object generics, like Foo<int>.

Here's the resulting PR: phpstan/phpstan-src#2818

We can't do this for objects, because I want new Collection([1, 2, 3]) to become Collection<int>. This could be improved in the future thanks to this suggestion: #6732 (comment) (but it's pretty complex to implement so for now it has to wait).

The new behaviour now only applies to bleeding edge (https://phpstan.org/blog/what-is-bleeding-edge) so definitely enable it to get the taste of the future 👍

[mitelg]

tried it out today and can confirm this is working! 🎉

thank you very much

[github-actions]

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