<?php

function yieldFromIteratorGeneratorThrows() {
    try {
        yield from new class(new ArrayIterator([1, -2])) extends IteratorIterator {
            public function key() {
                if ($k = parent::key()) {
                    throw new Exception;
                }
                return $k;
            }
        };
    } catch (Exception $e) {
        yield 2;
    }
}

foreach (yieldFromIteratorGeneratorThrows() as $k => $v) {
    var_dump($v);
}