From 8ce1aac477a33ab1fe2a0b590ff278518dc0e473 Mon Sep 17 00:00:00 2001
From: Olivia Kinnear <git@superatomic.dev>
Date: Sun, 23 Aug 2026 06:13:41 -0500
Subject: [PATCH] feat(pos): mutable vim.Pos, vim.Range fields #41318

Allow plugins to set the human-readable fields.
---
 runtime/lua/vim/pos.lua            | 22 ++++++++++++++++
 runtime/lua/vim/range.lua          | 42 +++++++++++++++++++++++++-----
 test/functional/lua/pos_spec.lua   | 11 ++++++++
 test/functional/lua/range_spec.lua | 13 +++++++++
 4 files changed, 81 insertions(+), 7 deletions(-)

diff --git a/runtime/lua/vim/pos.lua b/runtime/lua/vim/pos.lua
index 80ce0b6f9e..bb2e2a0597 100644
--- a/runtime/lua/vim/pos.lua
+++ b/runtime/lua/vim/pos.lua
@@ -55,6 +55,28 @@ function M.__index(pos, key)
   return M[key]
 end
 
+---@private
+---@param pos vim.Pos
+---@param key any
+---@param value any
+function M.__newindex(pos, key, value)
+  if key == 'row' then
+    validate('row', value, 'number')
+    pos[1] = value
+  elseif key == 'col' then
+    validate('col', value, 'number')
+    pos[2] = value
+  elseif key == 'buf' then
+    validate('buf', value, 'number')
+    if value == 0 then
+      value = api.nvim_get_current_buf()
+    end
+    pos[3] = value
+  else
+    rawset(pos, key, value)
+  end
+end
+
 ---@package
 ---@param buf integer
 ---@param row integer
diff --git a/runtime/lua/vim/range.lua b/runtime/lua/vim/range.lua
index e8dd7d8bb9..aafc8da65f 100644
--- a/runtime/lua/vim/range.lua
+++ b/runtime/lua/vim/range.lua
@@ -50,24 +50,52 @@ local util = require('vim.pos._util')
 local M = {}
 
 ---@private
----@param pos vim.Range
+---@param range vim.Range
 ---@param key any
-function M.__index(pos, key)
+function M.__index(range, key)
   if key == 'start_row' then
-    return pos[1]
+    return range[1]
   elseif key == 'start_col' then
-    return pos[2]
+    return range[2]
   elseif key == 'end_row' then
-    return pos[3]
+    return range[3]
   elseif key == 'end_col' then
-    return pos[4]
+    return range[4]
   elseif key == 'buf' then
-    return pos[5]
+    return range[5]
   end
 
   return M[key]
 end
 
+---@private
+---@param range vim.Range
+---@param key any
+---@param value any
+function M.__newindex(range, key, value)
+  if key == 'start_row' then
+    validate('start_row', value, 'number')
+    range[1] = value
+  elseif key == 'start_col' then
+    validate('start_col', value, 'number')
+    range[2] = value
+  elseif key == 'end_row' then
+    validate('end_row', value, 'number')
+    range[3] = value
+  elseif key == 'end_col' then
+    validate('end_col', value, 'number')
+    range[4] = value
+  elseif key == 'buf' then
+    validate('buf', value, 'number')
+    if value == 0 then
+      value = api.nvim_get_current_buf()
+    end
+    range[5] = value
+  else
+    rawset(range, key, value)
+  end
+end
+
 ---@package
 ---@overload fun(start: vim.Pos, end_: vim.Pos): vim.Range
 ---@overload fun(buf: integer, start_row: integer, start_col: integer, end_row: integer, end_col: integer): vim.Range
diff --git a/test/functional/lua/pos_spec.lua b/test/functional/lua/pos_spec.lua
index a252702023..fef9d86a52 100644
--- a/test/functional/lua/pos_spec.lua
+++ b/test/functional/lua/pos_spec.lua
@@ -41,6 +41,17 @@ describe('vim.pos', function()
     eq({ 1, 3, buf }, pos_default)
   end)
 
+  it('is modifiable', function()
+    local pos, buf = exec_lua(function()
+      local pos = vim.pos(-1, 5, 5)
+      pos.buf = 0
+      pos.row = 4
+      pos.col = 2
+      return pos, vim.api.nvim_get_current_buf()
+    end)
+    eq({ 4, 2, buf }, pos)
+  end)
+
   it('comparisons by overloaded operators', function()
     local buf = exec_lua(function()
       return vim.api.nvim_create_buf(false, true)
diff --git a/test/functional/lua/range_spec.lua b/test/functional/lua/range_spec.lua
index 5c83702ec3..c1e9f1708c 100644
--- a/test/functional/lua/range_spec.lua
+++ b/test/functional/lua/range_spec.lua
@@ -56,6 +56,19 @@ describe('vim.range', function()
     eq(success, false)
   end)
 
+  it('is modifiable', function()
+    local range, buf = exec_lua(function()
+      local range = vim.range(-1, 5, 5, 5, 5)
+      range.buf = 0
+      range.start_row = 4
+      range.start_col = 2
+      range.end_row = 6
+      range.end_col = 8
+      return range, vim.api.nvim_get_current_buf()
+    end)
+    eq({ 4, 2, 6, 8, buf }, range)
+  end)
+
   it('converts between vim.Range and lsp.Range', function()
     local buf = exec_lua(function()
       return vim.api.nvim_get_current_buf()