From: Jack Cherng <jfcherng@gmail.com>
Date: Sat, 13 Jul 2019 00:56:28 +0800
Subject: [PATCH] Fix access array offset on value of type null

Reference: https://twitter.com/nikita_ppv/status/1148931277216800769

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

--- a/lib/Doctrine/Common/Annotations/DocParser.php
+++ b/lib/Doctrine/Common/Annotations/DocParser.php
@@ -964,7 +964,8 @@ private function Identifier()
 
         $className = $this->lexer->token['value'];
 
-        while ($this->lexer->lookahead['position'] === ($this->lexer->token['position'] + strlen($this->lexer->token['value']))
+        while (null !== $this->lexer->lookahead
+                && $this->lexer->lookahead['position'] === ($this->lexer->token['position'] + strlen($this->lexer->token['value']))
                 && $this->lexer->isNextToken(DocLexer::T_NAMESPACE_SEPARATOR)) {
 
             $this->match(DocLexer::T_NAMESPACE_SEPARATOR);