From fa0cb7c8da1a71b388ba94fe876a87af6d39cad0 Mon Sep 17 00:00:00 2001
From: Permutator <permutatorem@gmail.com>
Date: Wed, 4 Jan 2017 15:46:48 -0800
Subject: [PATCH] Assert self.node_offset_box is None if fragment.node ==
 self.node_address

---
 components/layout/query.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/components/layout/query.rs b/components/layout/query.rs
index 21c1c37d0ae..39aeb1cef71 100644
--- a/components/layout/query.rs
+++ b/components/layout/query.rs
@@ -549,6 +549,10 @@ impl FragmentBorderBoxIterator for ParentOffsetBorderBoxIterator {
         if fragment.node == self.node_address {
             // Found the fragment in the flow tree that matches the
             // DOM node being looked for.
+
+            // If self.node_offset_box is Some, we were treating this as an inline node!
+            assert!(self.node_offset_box.is_none());
+
             self.has_processed_node = true;
             self.node_offset_box = Some(NodeOffsetBoxInfo {
                 offset: border_box.origin,