Nullable mixed array does not match string array when unpacking function result

[ndench]

Bug report

This seems like a crazy edge case. I have a function that takes a nullable mixed array. When I call this function and pass in a list that's built using the unpacked result of a function, I get an error:

function foo expects array<int, mixed>|null, array<int, string> given.

Code snippet that reproduces the problem

Here is the error:
https://phpstan.org/r/d2c5bf08-d6bf-4888-ab7c-9a1db035688b

The error disappears when the function parameter is not nullable.
https://phpstan.org/r/db2aa007-c7e2-484d-9ddc-3e336f2ac91d

The error also disappears when we do not unpack the result of another function.
https://phpstan.org/r/4fe5bcde-068f-4767-996e-46eba8af5f00

Expected output

I expect this to produce no errors.

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[phpstan-bot]

@ndench After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-19: Parameter #1 $foos of function foo expects array<int, mixed>|null, array<int, string> given.
+No errors

[ondrejmirtes]

Fixed: phpstan/phpstan-src@9f12f0f

[github-actions]

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