From 93552e2e314955bc6acc62b28296745a79857bfd Mon Sep 17 00:00:00 2001
From: flywind <43030857+xflywind@users.noreply.github.com>
Date: Mon, 23 Nov 2020 18:27:09 +0800
Subject: [PATCH] fix rope index (#16100)

* fix rope index

* add testcase

(cherry picked from commit ab2c082cb3e9e411571fa0936776762bc0c8fd94)
---
 lib/pure/ropes.nim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/pure/ropes.nim b/lib/pure/ropes.nim
index c2055cafca..e4e05ba47f 100644
--- a/lib/pure/ropes.nim
+++ b/lib/pure/ropes.nim
@@ -204,8 +204,8 @@ proc `[]`*(r: Rope, i: int): char {.rtl, extern: "nroCharAt".} =
       if x.left.length > j:
         x = x.left
       else:
+        dec(j, x.left.length)
         x = x.right
-        dec(j, x.len)
 
 iterator leaves*(r: Rope): string =
   ## iterates over any leaf string in the rope `r`.