🐛 Fix case string - custom annotation

Author: Vincent Langlet

Symfony3Custom/Sniffs/Commenting/DocCommentGroupSameTypeSniff.php

@@ -87,7 +87,8 @@ public function process(PHP_CodeSniffer_File $phpcsFile, $stackPtr)
                 $previousLine = max($previousStringLine, $previousTagLine);
 
                 $currentIsCustom = ! in_array($currentType, $this->tags);
-                $previousIsCustom = ! in_array($previousType, $this->tags);
+                $previousIsCustom = ($previousType !== '')
+                    && ! in_array($previousType, $this->tags);
 
                 if (($previousType === $currentType)
                     || ($currentIsCustom && $previousIsCustom)