From 74c687e395c946111652c7bef4780b0aa2391cbf Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Fri, 27 Nov 2020 15:26:57 +0100
Subject: [PATCH] fixes #16154; underlying system.add for seq is the real
 cause; will be addressed in a follow-up PR (#16161)

(cherry picked from commit c9a10bb9e47c5227b32f49f5876e965cc2308541)
---
 lib/pure/asyncdispatch.nim | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/pure/asyncdispatch.nim b/lib/pure/asyncdispatch.nim
index 90345676fe5d..e111f9e7dbdf 100644
--- a/lib/pure/asyncdispatch.nim
+++ b/lib/pure/asyncdispatch.nim
@@ -1199,9 +1199,10 @@ else:
     not p.selector.isEmpty() or p.timers.len != 0 or p.callbacks.len != 0
 
   proc prependSeq(dest: var seq[Callback]; src: sink seq[Callback]) =
-    let old = move dest
+    var old = move dest
     dest = src
-    dest.add old
+    for i in 0..high(old):
+      dest.add(move old[i])
 
   proc processBasicCallbacks(
     fd: AsyncFD, event: Event