Fixed some potential typing errors.

Author: hexydec

src/htmldoc.php

@@ -813,7 +813,7 @@ protected function htmlentities(string $html, string $charset) : string {
 		for ($i = 1; $i < 256; $i++) {
 			$str .= \chr($i);
 		}
-		$str = \mb_convert_encoding($str, \mb_internal_encoding(), $charset);
+		$str = (string) \mb_convert_encoding($str, \mb_internal_encoding(), $charset);
 
 		// build html entities conversion map
 		$replace = [];
@@ -825,7 +825,7 @@ protected function htmlentities(string $html, string $charset) : string {
 		}
 
 		// convert entities
-		$html = \mb_convert_encoding($html, 'HTML-ENTITIES');
+		$html = (string) \mb_convert_encoding($html, 'HTML-ENTITIES');
 		return \str_replace(\array_values($replace), \array_keys($replace), $html);
 	}
 }

src/tokens/tag.php

@@ -204,9 +204,9 @@ public function parse(tokenise $tokens) : void {
 	 * @return array An array of parent tag names
 	 */
 	protected function getParentTagNames() : array {
-		if (!$this->parenttags) {
+		if (empty($this->parenttags)) {
 			$this->parenttags = $this->parent ? $this->parent->getParentTagNames() : [];
-			if ($this->tagName) {
+			if ($this->tagName !== null) {
 				$this->parenttags[] = \mb_strtolower($this->tagName);
 			}
 		}
@@ -363,7 +363,7 @@ protected function getIndex() : ?int {
 	 * @return void
 	 */
 	public function before(array $nodes) : void {
-		if (($index = $this->getIndex()) !== null) {
+		if ($this->parent !== null && ($index = $this->getIndex()) !== null) {
 			$this->parent->append($nodes, $index);
 		}
 	}
@@ -375,7 +375,7 @@ public function before(array $nodes) : void {
 	 * @return void
 	 */
 	public function after(array $nodes) : void {
-		if (($index = $this->getIndex()) !== null) {
+		if ($this->parent !== null && ($index = $this->getIndex()) !== null) {
 			$this->parent->append($nodes, $index + 1);
 		}
 	}