Generic return type resolved from callable return type wrong

[rarila]

Bug report

As seen it the example code, a closure with return type of ''array<non-empty-string, string>'' is for some reason resolved as ''array<string, string>''.

Code snippet that reproduces the problem

https://phpstan.org/r/ef1c1257-f1a5-4a74-903d-7afaf6b91e9a

Expected output

Expected: ''array<non-empty-string, string>''
Got: ''array<string, string>''.

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

No response

[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 👍

[github-actions]

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