Description

When setting accept_word inside suggestion.keymap via lazy.nvim's opts (or LazyVim's default opts merge), the key mapping is never created. However, if I use the config function to directly call require("copilot").setup({...}) with the exact same configuration, the mapping works perfectly. Other keymaps like accept, next, prev are correctly registered under the same opts table. The underlying function require("copilot.suggestion").accept_word() works fine when called directly.

Steps to Reproduce

Method A (fails): Using opts

{
  "zbirenbaum/copilot.lua",
  cmd = "Copilot",
  event = "InsertEnter",
  opts = {
    suggestion = {
      enabled = true,
      auto_trigger = true,
      keymap = {
        accept_word = "<M-w>",   -- also tried single char "w", ";"
        accept = false,
        next = "<M-]>",
        prev = "<M-[>",
      },
    },
  },
}

After this configuration, press <M-w> while a suggestion is visible → nothing happens. :verbose imap <M-w> shows No mapping found.

Method B (works): Using config function

{
  "zbirenbaum/copilot.lua",
  cmd = "Copilot",
  event = "InsertEnter",
  config = function()
    require("copilot").setup({
      suggestion = {
        enabled = true,
        auto_trigger = true,
        keymap = {
          accept_word = "<M-w>",
          accept = false,
          next = "<M-]>",
          prev = "<M-[>",
        },
      },
    })
  end,
}

After this configuration, pressing <M-w> while a suggestion is visible correctly accepts the first word. :verbose imap <M-w> shows the mapping.

Expected Behavior

Both opts and config approaches should produce the same result: the accept_word keymap should be registered.

Actual Behavior

Only the config approach works. The opts approach fails to register the accept_word mapping, while other keymaps (accept, next, prev) work fine in both approaches.

Additional Observations

• Calling require("copilot.suggestion").accept_word() directly (e.g., via :lua) works correctly – the function itself is not broken.
• The issue is specifically about keymap registration when using opts. It seems the accept_word entry in the keymap table is silently ignored during the setup process when configuration comes from merged opts.
• Using a single character ("w", ";") instead of a modifier combination ("<M-w>") also fails in the opts approach.

Environment

• Neovim version: 0.11.0+
• Plugin manager: lazy.nvim (also tested with LazyVim distribution)
• copilot.lua version: latest (commit d521d39 as of testing)
• OS: Linux / macOS

Possible Cause

The difference between opts and config suggests that lazy.nvim's opts merging process may alter the keymap table in a way that causes accept_word to be dropped or not recognized by copilot.lua's internal setup. Alternatively, copilot.lua's handling of keymap may have a condition that only applies when the table comes from certain sources.

Workaround

Use config function to call require("copilot").setup(...) directly – this is the reliable way to configure accept_word.