go.nvim/lua/go/lsp_diag.lua

-- hdlr alternatively, use lua vim.lsp.diagnostic.set_loclist({open_loclist = false})
-- true to open loclist
-- local diag_hdlr = function(err, method, result, client_id, bufnr, config)
-- New signature on_publish_diagnostics({_}, {result}, {ctx}, {config})
debug = debug or nil
local vfn = vim.fn

local function hdlr(result)
  if result and result.diagnostics then
    local item_list = {}
    local s = result.uri
    local fname = s
    for _, v in ipairs(result.diagnostics) do
      local _, j = string.find(s, 'file://')
      if j then
        fname = string.sub(s, j + 1)
      end
      table.insert(item_list, {
        filename = fname,
        lnum = v.range.start.line + 1,
        col = v.range.start.character + 1,
        text = v.message,
      })
    end
    local old_items = vfn.getqflist()
    for _, old_item in ipairs(old_items) do
      if vim.uri_from_bufnr(old_item.bufnr) ~= result.uri then
        table.insert(item_list, old_item)
      end
    end
    vfn.setqflist({}, ' ', { title = 'LSP', items = item_list })
  end
end

local diag_hdlr_0_6 = function(err, result, ctx, config)
  -- vim.lsp.diagnostic.clear(vfn.bufnr(), client.id, nil, nil)
  vim.lsp.diagnostic.on_publish_diagnostics(err, result, ctx, config)
  hdlr(result)
end

vim.lsp.handlers['textDocument/publishDiagnostics'] = vim.lsp.with(diag_hdlr_0_6, {
  -- Enable underline, use default values
  underline = _GO_NVIM_CFG.lsp_diag_underline,
  -- Enable virtual text, override spacing to 0
  virtual_text = _GO_NVIM_CFG.lsp_diag_virtual_text,
  -- Use a function to dynamically turn signs off
  -- and on, using buffer local variables
  signs = _GO_NVIM_CFG.lsp_diag_signs,
  -- Disable a feature
  update_in_insert = _GO_NVIM_CFG.lsp_diag_update_in_insert,
})