No sign is displayed in Vim8 when "diagnostic.enableHighlightLineNumber" is "true"

[yaegassy]

Result from CocInfo

## versions

vim version: VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Mar 23 2020 06:10:20)
node version: v12.13.1
coc.nvim version: 0.0.77
term: iTerm.app
platform: darwin

## Output channel: eslint

[Info  - 10:26:04] ESLint server running in node v12.13.1
[Info  - 10:26:05] ESLint library loaded from: /private/tmp/coc-issue-proj/node_modules/eslint/lib/api.js

Describe the bug

The default value for diagnostic.enableHighlightLineNumber is currently set to true.

No sign is displayed in Vim8 when "diagnostic.enableHighlightLineNumber" is "true".

Vim8 is experiencing this symptom.

No problem with Neovim.

Reproduce the bug

• Install eslint extension on coc.nvim beforehand. :CocInstall coc-eslint

• Install eslint in the typescript project and create eslintrc.json

  npm init -y
  npx eslint --init

• Create file mini.vimrc with：

  set runtimepath^=/tmp/coc.nvim
  filetype plugin indent on
  syntax on
  set hidden
  set laststatus=2
  
  let g:coc_config_home = expand('/tmp/coc-issue-proj')
  let g:coc_data_home = expand('/tmp/coc-issue-extension')

• Run :CocConfig to create coc-settings.json (minimal)

  {
  "diagnostic.enableHighlightLineNumber": true
  }

• Start vim with command: vim -Nu mini.vimrc index.ts

  // index.ts
  const foo = "";

• Operate vim.

• !!!PROBLEM!!!: The sign is not displayed.

• Run :CocConfig and set diagnostic.enableHighlightLineNumber to false.

• Run :CocRestart.

• OK: sign displayed

Screenshots (Demo)

[yaegassy]

Thank you for the fix!