--- a/mercurial/commands.py	Mon Mar 20 11:38:37 2017 +0900
+++ b/mercurial/commands.py	Tue Mar 14 17:43:18 2017 -0700
@@ -5349,6 +5349,11 @@
     if rev and node:
         raise error.Abort(_("please specify just one revision"))
 
+    if ui.configbool('commands', 'update.requiredest', False):
+        if not node and not rev and not date:
+            raise error.Abort(_('you must specify a destination'),
+                              hint=_('for example: hg update ".::"'))
+
     if rev is None or rev == '':
         rev = node