--- a/mercurial/commands.py	Wed Jul 11 21:23:18 2018 +0900
+++ b/mercurial/commands.py	Wed Jul 11 21:35:31 2018 +0900
@@ -2535,6 +2535,8 @@
     diff = opts.get('all') or opts.get('diff')
     if diff and opts.get('all_files'):
         raise error.Abort(_('--diff and --all-files are mutually exclusive'))
+    if opts.get('all_files') and not opts.get('rev'):
+        opts['rev'] = ['wdir()']
 
     reflags = re.M
     if opts.get('ignore_case'):