Bug report

ImplodeFunctionRule does not handle union types and therefore passing nullable array as second argument to the function does not show any error message but fails at runtime.

Using nullable array as 1st argument of implode/join function or passing other union type (then nullable array) works as expected but that's thanks to the \PHPStan\Rules\Functions\CallToFunctionParametersRule.

Code snippet that reproduces the problem

https://phpstan.org/r/65455304-be62-4b88-9ff9-6c98c4b0aff8