diff --git a/src/Psalm/ErrorBaseline.php b/src/Psalm/ErrorBaseline.php
index 227132769d2..9a22ec8295b 100644
--- a/src/Psalm/ErrorBaseline.php
+++ b/src/Psalm/ErrorBaseline.php
@@ -269,7 +269,7 @@ private static function writeToFile(
                     $codeNode = $baselineDoc->createElement('code');
                     $textContent = trim($selection);
                     if ($textContent !== htmlspecialchars($textContent)) {
-                        $codeNode->append($baselineDoc->createCDATASection($textContent));
+                        $codeNode->appendChild($baselineDoc->createCDATASection($textContent));
                     } else {
                         $codeNode->textContent = trim($textContent);
                     }