generator.nonIterable - Phpstan

Code example

php

<?php declare(strict_types = 1);

/** @return \Generator<int> */
function doFoo(): \Generator
{
	$value = 42;
	yield from $value;
}

Why is it reported?

The expression passed to yield from is not iterable. yield from requires an iterable argument such as an array, a Traversable, or another Generator. In the example above, $value is an int, which cannot be iterated.

How to fix it

Pass an iterable expression to yield from:

diff-php

 <?php declare(strict_types = 1);

 /** @return \Generator<int> */
 function doFoo(): \Generator
 {
-	$value = 42;
-	yield from $value;
+	$values = [42];
+	yield from $values;
 }