`array_count_values` returned value is not taking care of the key-type

[niconoe-]

Bug report

Hello !

When calling array_count_values, PHPStan's dumped type for the returned value is array<int<…>>, ignoring the definition of the type of the keys for such array.

When working with a list of integers or a list of strings (or Stringable objects), it should return respectively array<int, int<…>> or array<string, int<…>>, as the values of the given array as argument become (after cast into array-key pseudotype) the keys of the returned array by array_count_values.
When working with a list of mixed integers and string (or Stringable objects), it could be left as is, or explicitly be array<array-key, int<…>>.

Thanks a lot!

Code snippet that reproduces the problem

https://phpstan.org/r/fc787ecb-635e-4655-bb3e-309e47db44f4

Expected output

Expected errors displayed by the Playground:

11 Dumped type: array<string, int<1, max>>

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[staabm]

Sounds like a good first issue to contribute.

Have a look at other existing *ReturnTypeExtensions and give it a go