From aa1f876de32789775dd563cc7e5fe426658af520 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <dmalyshau@mozilla.com>
Date: Tue, 23 Apr 2019 17:26:31 -0400
Subject: [PATCH] Assert on a mapping buffer being used

---
 wgpu-native/src/device.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/wgpu-native/src/device.rs b/wgpu-native/src/device.rs
index 8a0f8c38d4..522797ff4b 100644
--- a/wgpu-native/src/device.rs
+++ b/wgpu-native/src/device.rs
@@ -1144,7 +1144,9 @@ pub extern "C" fn wgpu_queue_submit(
 
                 // update submission IDs
                 for id in comb.trackers.buffers.used() {
-                    buffer_guard[id]
+                    let buffer = &buffer_guard[id];
+                    assert!(buffer.pending_map_operation.is_none());
+                    buffer
                         .life_guard
                         .submission_index
                         .store(submit_index, Ordering::Release);