Add non regression test (#5035)

Author: VincentLanglet

tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php

@@ -3900,6 +3900,14 @@ public function testBug6120(): void
 		$this->analyse([__DIR__ . '/data/bug-6120.php'], []);
 	}
 
+	public function testBug1501(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->analyse([__DIR__ . '/data/bug-1501.php'], []);
+	}
+
 	public function testBug11463(): void
 	{
 		$this->checkThisOnly = false;

tests/PHPStan/Rules/Methods/data/bug-1501.php

@@ -0,0 +1,32 @@
+<?php declare(strict_types = 1);
+
+namespace Bug1501;
+
+class HelloWorld
+{
+	public function sayHello(): void
+	{
+		$so = new SomeObject();
+		$this->modify($so->getForModify());
+	}
+
+	private function modify(array &$data): void
+	{
+		$data[] = 'abc';
+	}
+}
+
+class SomeObject
+{
+	private $someVar;
+
+	public function __construct()
+	{
+		$this->someVar = [];
+	}
+
+	public function &getForModify(): array
+	{
+		return $this->someVar;
+	}
+}