diff --git a/src/Row.php b/src/Row.php
index 0dd2f46..63e79c3 100644
--- a/src/Row.php
+++ b/src/Row.php
@@ -430,6 +430,10 @@ class Row {
 	protected function updateSyntaxPHP():void
 	{
 		// The index for the tokens should exist
+		if ( ! array_key_exists($this->idx + 1, $this->parent->syntax->tokens))
+		{
+			return;
+		}
 		$tokens = $this->parent->syntax->tokens[$this->idx + 1];
 
 		// $inComment = ($this->idx > 0 && $this->parent->rows[$this->idx - 1]->hlOpenComment);