https://phpstan.org/r/50a1171b-7243-4e7d-a9d4-9d0b21cc1d02

"Call to function array_key_exists() with non-empty-string and array will always evaluate to true."

I disabled the following error message using checkMissingIterableValueType: false:
"Function foo() has parameter $arr with no value type specified in iterable type array."
Adding a typehint for for the array makes the other error go away, but that's not the point here.