From 3d3545bbc17627a46ee85ce8e85bdd75523c3982 Mon Sep 17 00:00:00 2001
From: Shougo <Shougo.Matsu@gmail.com>
Date: Mon, 2 Jan 2017 00:07:49 +0900
Subject: [PATCH] vim-patch:7.4.1834 (#5854)

Problem:    Possible crash when conceal is active.
Solution:   Check for the screen to be valid when redrawing a line.

https://github.com/vim/vim/commit/908be438794619f10ef7fa25e24e5893b2ae0189
---
 src/nvim/screen.c  | 5 +++++
 src/nvim/version.c | 1 +
 2 files changed, 6 insertions(+)

diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 50517d2829..bf6e316c06 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -486,6 +486,11 @@ void update_single_line(win_T *wp, linenr_T lnum)
   int row;
   int j;
 
+  // Don't do anything if the screen structures are (not yet) valid.
+  if (!screen_valid(true)) {
+    return;
+  }
+
   if (lnum >= wp->w_topline && lnum < wp->w_botline
       && foldedCount(wp, lnum, &win_foldinfo) == 0) {
     row = 0;
diff --git a/src/nvim/version.c b/src/nvim/version.c
index be17b6775a..cfe71c5015 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -606,6 +606,7 @@ static int included_patches[] = {
   1837,
   1836,
   1835,
+  1834,
   1833,
   1832,
   1831,