From 752e8677bdba7338d3af93a0a226ba4697e669fc Mon Sep 17 00:00:00 2001
From: Hixie <github.com@spam.hixie.ch>
Date: Fri, 20 Nov 2015 16:08:12 -0800
Subject: [PATCH] Assert: don't push a PageRoute over a PopupRoute.

"Fixes" #389.
---
 packages/flutter/lib/src/widgets/routes.dart | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/flutter/lib/src/widgets/routes.dart b/packages/flutter/lib/src/widgets/routes.dart
index 78ba2bcc503..1046e7028e2 100644
--- a/packages/flutter/lib/src/widgets/routes.dart
+++ b/packages/flutter/lib/src/widgets/routes.dart
@@ -350,6 +350,10 @@ abstract class ModalRoute<T> extends TransitionRoute<T> {
 abstract class PopupRoute<T> extends ModalRoute<T> {
   PopupRoute({ Completer<T> completer }) : super(completer: completer);
   bool get opaque => false;
+  bool willPushNext(Route nextRoute) {
+    assert(nextRoute is! PageRoute);
+    return super.willPushNext(nextRoute);
+  }
 }
 
 /// A modal route that replaces the entire screen.