Bug report

Using mixed as explicit type with function argument on PHP 7.4 is not reported as an error.

Configuration file has phpVersion option set to 70400.

Code snippet that reproduces the problem

https://phpstan.org/r/d86d4cdd-b7ee-4f2b-a5cb-1a0d4ced3bb5

Expected output

Parameter $mixed of anonymous function has invalid typehint type mixed.

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PHPStan has helped me today to add a lot more clarity and confidence to old PHP code that would otherwise be scary to make changes in 🙂

It always makes me feel happy to fix all of the errors that PHPStan reports, and to bring new files into our existing PHPStan coverage at the strictest level 🙂