added regression test

Author: staabm

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1091,6 +1091,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Comparison/data/bug-8169.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7519.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8087.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-5785.php');
 	}
 
 	/**

tests/PHPStan/Analyser/data/bug-5785.php

@@ -0,0 +1,33 @@
+<?php declare(strict_types=1);
+
+namespace Bug5785;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+}
+
+class IterableHelper
+{
+	/**
+	 * @template T
+	 * @param iterable<T> $iterable
+	 * @param-out iterable<T> $iterable
+	 */
+	public static function act(iterable &$iterable): void
+	{
+	}
+}
+
+function doFoo() {
+	/** @var HelloWorld[] $a */
+	$a = [];
+
+	assertType('array<Bug5785\HelloWorld>', $a);
+	IterableHelper::act($a);
+	assertType('iterable<Bug5785\HelloWorld>', $a);
+
+}
+
+