patch 7.4.1853
Problem:    Crash when job and channel are in the same dict while using
            partials. (Luc Hermitte)
Solution:   Do not decrement the channel reference count too early.
diff --git a/src/channel.c b/src/channel.c
index f4dc323..94681ee 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -2566,7 +2566,6 @@
 	      clear_tv(&rettv);
 	      channel_need_redraw = TRUE;
 	  }
-	  --channel->ch_refcount;
 
 	  /* the callback is only called once */
 	  vim_free(channel->ch_close_cb);
@@ -2574,6 +2573,8 @@
 	  partial_unref(channel->ch_close_partial);
 	  channel->ch_close_partial = NULL;
 
+	  --channel->ch_refcount;
+
 	  if (channel_need_redraw)
 	  {
 	      channel_need_redraw = FALSE;