From e982b9131e9c92d70dd5994910c1eb8ca644f2f2 Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter1138@openttd.org>
Date: Wed, 30 Jan 2019 09:20:07 +0000
Subject: [PATCH] Fix #7142: Missing map bounds check when building long roads.

---
 src/road_cmd.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/road_cmd.cpp b/src/road_cmd.cpp
index 175e776e5e..d9825c9bfa 100644
--- a/src/road_cmd.cpp
+++ b/src/road_cmd.cpp
@@ -809,7 +809,9 @@ do_clear:;
  */
 static bool CanConnectToRoad(TileIndex tile, RoadType rt, DiagDirection dir)
 {
-	RoadBits bits = GetAnyRoadBits(tile + TileOffsByDiagDir(dir), rt, false);
+	tile += TileOffsByDiagDir(dir);
+	if (!IsValidTile(tile)) return false;
+	RoadBits bits = GetAnyRoadBits(tile, rt, false);
 	return (bits & DiagDirToRoadBits(ReverseDiagDir(dir))) != 0;
 }