From 5f1f5a8c2a00145eb4bfbb5979efa14934ef90cf Mon Sep 17 00:00:00 2001
From: Volodymyr Chernetskyi <19735328+chernetskyi@users.noreply.github.com>
Date: Fri, 4 Sep 2026 18:25:14 +0200
Subject: fix(treesitter): conceal_lines is not applied to injected trees

Problem:
TSHighlighter._on_conceal_line() parses with the range { row, row }. A
Range2 has an exclusive end, so that is the empty range, and no injected
region ever intercepts it.

The root tree is parsed regardless, because its region is empty, so only
injections are affected: conceal_lines metadata coming from an injected
language's highlights query is dropped. on_range_impl() then records the
row in _conceal_checked, so the miss persists until the buffer changes.

For a markdown code block nested in a markdown code block, the inner
fence delimiters stay visible and nvim_win_text_height() reports 5 rows
where 3 are displayed.

Solution:
Pass the one-row range, as the on_range_impl() call below already does.

AI-assisted
---
 runtime/lua/vim/treesitter/highlighter.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'runtime/lua/vim')

diff --git a/runtime/lua/vim/treesitter/highlighter.lua b/runtime/lua/vim/treesitter/highlighter.lua
index b5ddd28aa2..f7e22eb5ff 100644
--- a/runtime/lua/vim/treesitter/highlighter.lua
+++ b/runtime/lua/vim/treesitter/highlighter.lua
@@ -549,7 +549,7 @@ function TSHighlighter._on_conceal_line(_, _, buf, row)
 
   -- Do not affect potentially populated highlight state.
   local highlight_states = self._highlight_states
-  self.tree:parse({ row, row })
+  self.tree:parse({ row, row + 1 })
   self:prepare_highlight_states(row, row)
   on_range_impl(self, buf, row, 0, row + 1, 0, false, true)
   self._highlight_states = highlight_states
-- 
cgit