minimal config for bug repro

init.vim

call plug#begin(expand('<sfile>:p:h') . '/plugged')
Plug 'neovim/nvim-lspconfig'
Plug 'hrsh7th/cmp-nvim-lsp'
Plug 'hrsh7th/cmp-buffer'
Plug 'hrsh7th/nvim-cmp'
Plug 'nvim-lua/plenary.nvim'
Plug 'scalameta/nvim-metals'

" For vsnip user.
Plug 'hrsh7th/cmp-vsnip'
Plug 'hrsh7th/vim-vsnip'

" For luasnip user.
" Plug 'L3MON4D3/LuaSnip'
" Plug 'saadparwaiz1/cmp_luasnip'

" For ultisnips user.
" Plug 'SirVer/ultisnips'
" Plug 'quangnguyen30192/cmp-nvim-ultisnips'

call plug#end()

set completeopt=menu,menuone,noselect

lua <<EOF
  -- Setup nvim-cmp.
  local cmp = require'cmp'

  cmp.setup({
    snippet = {
      expand = function(args)
        -- For `vsnip` user.
        vim.fn["vsnip#anonymous"](args.body)

        -- For `luasnip` user.
        -- require('luasnip').lsp_expand(args.body)

        -- For `ultisnips` user.
        -- vim.fn["UltiSnips#Anon"](args.body)
      end,
    },
    mapping = {
      ['<C-d>'] = cmp.mapping.scroll_docs(-4),
      ['<C-f>'] = cmp.mapping.scroll_docs(4),
      ['<C-Space>'] = cmp.mapping.complete(),
      ['<C-e>'] = cmp.mapping.close(),
      ['<CR>'] = cmp.mapping.confirm({ select = true }),
    },
    sources = {
      { name = 'nvim_lsp' },

      -- For vsnip user.
      { name = 'vsnip' },

      -- For luasnip user.
      -- { name = 'luasnip' },

      -- For ultisnips user.
      -- { name = 'ultisnips' },

      { name = 'buffer' },
    }
  })

  -- Setup lsp.
  metals_config = require("metals").bare_config
  metals_config.init_options.statusBarProvider = "on"
  metals_config.settings = { showImplicitArguments = true }
  metals_config.on_attach = on_attach
  metals_config.capabilities = require('cmp_nvim_lsp').update_capabilities(vim.lsp.protocol.make_client_capabilities())
EOF
augroup lsp
	au!
	au FileType scala,sbt lua require("metals").initialize_or_attach({})
augroup end