Example for how the same array is re-validated multiple times instead of validating it once/keeping track of its types.

ArrayOf.php

<?php

class MyClass
{
    public function doSomething(Foo[] $array) { // First check here.
        if ($this->hasSomeElement($array)) {
            $this->doSomethingBranch1($array);
        } else {
            $this->doSomethingBranch2($array);
        }
    }
    
    private function hasSomeElement(Foo[] $array) { // Second validation here (unnecessary)
        foreach ($array as $v) {
            if ($v->isTrue()) {
                return true;
            }
        }
        
        return false;
    }
    
    private function doSomethingBranch1(Foo[] $array) { // Third validation here (unnecessary)
        // ...
    }
    
    private function doSomethingBranch2(Foo[] $array) { // Another validation here (unnecessary)
        // ...
    }
}