diff --git a/lua/render/compiler.lua b/lua/render/compiler.lua
index 78b2aec..7d2a1d4 100644
--- a/lua/render/compiler.lua
+++ b/lua/render/compiler.lua
@@ -114,14 +114,16 @@ function M.stop(bufnr)
     return
   end
   log.dbg('stopping process for buffer %d', bufnr)
-  proc.obj:kill('sigterm')
+  ---@type fun(self: table, signal: string|integer)
+  local kill = proc.obj.kill
+  kill(proc.obj, 'sigterm')
 
   local timer = vim.uv.new_timer()
   if timer then
     timer:start(5000, 0, function()
       timer:close()
       if active[bufnr] and active[bufnr].obj == proc.obj then
-        proc.obj:kill('sigkill')
+        kill(proc.obj, 'sigkill')
         active[bufnr] = nil
       end
     end)
diff --git a/lua/render/diagnostic.lua b/lua/render/diagnostic.lua
index 8e9658f..a526219 100644
--- a/lua/render/diagnostic.lua
+++ b/lua/render/diagnostic.lua
@@ -12,7 +12,7 @@ end
 
 ---@param bufnr integer
 ---@param name string
----@param error_parser fun(stderr: string, ctx: render.Context): vim.Diagnostic[]
+---@param error_parser fun(stderr: string, ctx: render.Context): render.Diagnostic[]
 ---@param stderr string
 ---@param ctx render.Context
 function M.set(bufnr, name, error_parser, stderr, ctx)
diff --git a/lua/render/init.lua b/lua/render/init.lua
index a04192b..73f3057 100644
--- a/lua/render/init.lua
+++ b/lua/render/init.lua
@@ -4,7 +4,7 @@
 ---@field cwd? string|fun(ctx: render.Context): string
 ---@field env? table<string, string>
 ---@field output? string|fun(ctx: render.Context): string
----@field error_parser? fun(stderr: string, ctx: render.Context): vim.Diagnostic[]
+---@field error_parser? fun(stderr: string, ctx: render.Context): render.Diagnostic[]
 ---@field clean? string[]|fun(ctx: render.Context): string[]
 
 ---@class render.Config
@@ -18,8 +18,17 @@
 ---@field root string
 ---@field ft string
 
+---@class render.Diagnostic
+---@field lnum integer
+---@field col integer
+---@field message string
+---@field severity? integer
+---@field end_lnum? integer
+---@field end_col? integer
+---@field source? string
+
 ---@class render.Process
----@field obj vim.SystemObj
+---@field obj table
 ---@field provider string
 ---@field output_file string