plugconf function is skipped when vimlparser failed to parse script

[tyru]

Problem

The plugconf function for https://github.com/t9md/vim-quickhl

" Plugin configuration like the code written in vimrc.
" This configuration is executed *before* a plugin is loaded.
function! s:on_load_pre()
  nmap <Space>m <Plug>(quickhl-manual-this)
  xmap <Space>m <Plug>(quickhl-manual-this)
  nmap <Space>M <Plug>(quickhl-manual-reset)
  xmap <Space>M <Plug>(quickhl-manual-reset)

  " the first color is unreadable on colorscheme seoul256
  let g:quickhl_manual_colors = [
  "\ "cterm=bold ctermfg=16 ctermbg=153 gui=bold guifg=#ffffff guibg=#0a7383",
  \ "cterm=bold ctermfg=7  ctermbg=1   gui=bold guibg=#a07040 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=2   gui=bold guibg=#4070a0 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=3   gui=bold guibg=#40a070 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=4   gui=bold guibg=#70a040 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=5   gui=bold guibg=#0070e0 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=6   gui=bold guibg=#007020 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=21  gui=bold guibg=#d4a00d guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=22  gui=bold guibg=#06287e guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=45  gui=bold guibg=#5b3674 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=16  gui=bold guibg=#4c8f2f guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=50  gui=bold guibg=#1060a0 guifg=#ffffff",
  \ "cterm=bold ctermfg=7  ctermbg=56  gui=bold guibg=#a0b0c0 guifg=black",
  \ ]
endfunction

The above function is skipped because current vimlparser doesn't support comment (\") in dictionary literal.
All functions in the file are ignored with no warnings/errors.

Expected

Volt should show the errors of vimlparser.