Preventing use of false as an array key

[M1ke]

https://psalm.dev/r/b5c9862354

In the given example we are wanting to search for an instance of a string in a list and unset it. However due to PHP's type coercion we accidentally unset the first element in our list instead because array_search returns false, and unsetting false coerces to 0.

As far as I see Psalm isn't flagging anything here.

I believe Psalm should be able to flag if a potential boolean value is used as an array key as some form of error - bool false is never an appropriate array-key - if somebody wishes to use potential false as an array key they should type cast it (e.g. 'false' would be a legitimate array key, as would 0)

[orklah]

Seems like a case where the ignoreInternalFunctionFalseReturn config should make a difference, but it doesn't