diff --git a/src/Composer/Downloader/FileDownloader.php b/src/Composer/Downloader/FileDownloader.php
index aeb655be4..4508eb294 100644
--- a/src/Composer/Downloader/FileDownloader.php
+++ b/src/Composer/Downloader/FileDownloader.php
@@ -75,7 +75,7 @@ abstract class FileDownloader implements DownloaderInterface
                 ),
             ));
 
-            copy($url, $filename, $ctx);
+            copy($url, $fileName, $ctx);
         } else {
             copy($url, $fileName);
         }