diff -r cf532a62e337 -r 0ebd94ac56d1 mercurial/hg.py
--- a/mercurial/hg.py	Fri Dec 15 17:52:38 2017 -0500
+++ b/mercurial/hg.py	Thu Dec 14 15:03:55 2017 -0800
@@ -916,8 +916,13 @@
     return _incoming(display, subreporecurse, ui, repo, source, opts)
 
 def _outgoing(ui, repo, dest, opts):
-    dest = ui.expandpath(dest or 'default-push', dest or 'default')
-    dest, branches = parseurl(dest, opts.get('branch'))
+    path = ui.paths.getpath(dest, default=('default-push', 'default'))
+    if not path:
+        raise error.Abort(_('default repository not configured!'),
+                hint=_("see 'hg help config.paths'"))
+    dest = path.pushloc or path.loc
+    branches = path.branch, opts.get('branch') or []
+
     ui.status(_('comparing with %s\n') % util.hidepassword(dest))
     revs, checkout = addbranchrevs(repo, repo, branches, opts.get('rev'))
     if revs: