Improved Enum support with regard to comparisons

[Seldaek]

Feature request

I am in the process of converting existing code to use enums in Monolog, and I noticed that PHPStan wasn't being as helpful as it could be.

See https://phpstan.org/r/920189df-c1f3-4b59-a816-02b8369fb16f for some expected errors which are missing.

See also https://3v4l.org/I2MUn#v8.1.5 for actual output.

The TL;DR is that when you have code like if ($foo < $bar) and then you convert it to enums and suddenly $foo and $bar are enum cases instead of int values, your code breaks but PHPStan does not tell you that this will now always return false.

[ondrejmirtes]

Wow, check how easy this was :) phpstan/phpstan-src@f7d80d6

As for the other situations, one of them is covered by strict-rules (or enabling https://phpstan.org/config-reference#checkalwaystruestrictcomparison): https://phpstan.org/r/01b303cf-85b5-48fb-a3b7-06b814595682

The loose comparison == is a hands-off thing for PHPStan because it's really messy for different types (I don't want to code the famous "loose comparisons" table from https://www.php.net/manual/en/types.comparisons.php).

[ondrejmirtes]

We should probably do the same thing for all objects, only some of them can be compared with < etc. like DateTimes or GMP.

[Seldaek]

Wow, check how easy this was :) phpstan/phpstan-src@f7d80d6

Cool, thanks!

As for the other situations, one of them is covered by strict-rules (or enabling https://phpstan.org/config-reference#checkalwaystruestrictcomparison): https://phpstan.org/r/01b303cf-85b5-48fb-a3b7-06b814595682

Ahh I didn't realize, will make sure to add strict rules on monolog repo 👍🏻

The loose comparison == is a hands-off thing for PHPStan because it's really messy for different types (I don't want to code the famous "loose comparisons" table from https://www.php.net/manual/en/types.comparisons.php).

I'd argue it should be doable for specific cases where the types are known and the same on left/right, but up to you. I added it mostly for completeness.

[github-actions]

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