Dynamic DOM return type

Author: VincentLanglet

stubs/dom.stub

@@ -41,6 +41,27 @@ class DOMNode
 	 */
 	public function hasAttributes() {}
 
+	/**
+	 * @template TNode of DOMNode
+	 * @param TNode $node
+	 * @return __benevolent<TNode|false>
+	 */
+	public function insertBefore(DOMNode $node, ?DOMNode $child = null) {}
+
+	/**
+	 * @template TNode of DOMNode
+	 * @param TNode $node
+	 * @return __benevolent<TNode|false>
+	 */
+	public function removeChild(DOMNode $node) {}
+
+	/**
+	 * @template TNode of DOMNode
+	 * @param TNode $node
+	 * @return __benevolent<TNode|false>
+	 */
+	public function appendChild(DOMNode $node) {}
+
 }
 
 class DOMElement extends DOMNode

tests/PHPStan/Analyser/nsrt/bug-9200.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Bug9200;
+
+use function PHPStan\Testing\assertType;
+
+function test(\DOMElement $element, \DOMNode $node): void
+{
+	assertType('(DOMElement|false)', $node->appendChild($element));
+	assertType('(DOMNode|false)', $element->appendChild($node));
+	assertType('(DOMElement|false)', $node->removeChild($element));
+	assertType('(DOMNode|false)', $element->removeChild($node));
+	assertType('(DOMElement|false)', $node->insertBefore($element, $node));
+	assertType('(DOMNode|false)', $node->insertBefore($node, $element));
+	assertType('(DOMNode|false)', $element->insertBefore($node, $node));
+}