PHP Traversable type hint

Question

I have a relatively simple function which uses a foreach

function foo($t) {
     $result;
     foreach($t as $val) {
         $result = dosomething($result, $val);
     }
     return $result;
}

I would like to type hint, and Traversable seems to be the exact type hint I need

 function foo(Traversable $t) {

However this gives a E_RECOVERABLE_ERROR when using an array (which is of course usable in a foreach): example

 Argument 1 passed to foo() must implement interface Traversable, array given

Is there a way to type hint or is this not possible?

Answer 1

PHP 7.1 introduces the iterable type declaration for this purpose, which accepts both arrays and instances of \Traversable.

In previous versions, you'll have to omit the type declaration.