False is broadened to bool when passed as argument

[Csardelacal]

Bug report

When a function receives false as a parameter to a call that is using a template, false is treated as bool. This is very prominent in optional functions that return a second value if the first one does not fulfill a condition.

Code snippet that reproduces the problem

https://phpstan.org/r/f005b006-ae63-4d4e-8b78-7e7e802f53a7

Expected output

I think this code should pass. I understand why PHPStan assumes that a parameter with a false value is a boolean, but since it is (in the example) never true, it could just as well be treated as false.

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

Yes. PHPStan is like the three reviewers I do not have. <3

[ondrejmirtes]

Duplicate of #7944

But you can solve your issue with a conditional type instead of generics: https://phpstan.org/writing-php-code/phpdoc-types#conditional-return-types

[github-actions]

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