We do similar (strict_types, declare parameter and return types, etc), but don't go as far as the Java-style collection classes except where absolutely necessary.

As a mostly-acceptable alternative, we just type hint as array and document the actual containing types in the phpdoc block and run phan for static analysis to catch any potential screwups.

    /**
     * Method for converting Foos into Bars
     *
     * @param Foo[] $foos
     * @return Bar[]
     */
    function convertFoosToBars(array $foos): array
    {
        // ...
    }

In theory this isn't perfect. In practice we haven't run into any issues yet.