Problem:
Accepting an item from another completion source raises an error when its
user_data.nvim table does not contain LSP metadata.

Solution:
Retrieve and guard the nested LSP metadata before accessing its fields.

Cover acceptance of a foreign completion item without LSP metadata.

AI-assisted

Problem:
An empty snippet insertText falls back to the label during selection, but
acceptance clears that label and expands an empty string.

Solution:
Require nonempty insertText before expanding a snippet without textEdit.

Extend the omnifunc acceptance fixture with an empty snippet insertion.

AI-assisted

Problem:
A completion list default edit range can replace the explicit range of an
InsertReplaceEdit, filtering out valid items or changing their replacement.

Solution:
Only synthesize a default text edit when the completion item has none.

Extend the existing itemDefaults test for explicit edits with both range variants.

AI-assisted

Problem:
Snippet completion words and previews prefer insertText even when textEdit
is present, although the actual expansion uses textEdit.newText.

Solution:
Use the text edit before the fallback insertion text in both selectors.

Extend the existing precedence test to check the snippet word and preview.

AI-assisted

Problem:
vim.lsp.completion.get() always asks every client that has completion
enabled in the buffer, so a mapping cannot ask just some of them.

Solution:
Add a "client_id" option that limits the request to the given client,
or clients if it is a list.

fix(lua): enable param-type-mismatch diagnostic

Problem:
After an LSP client restart, the completion reload callback can use an old
client ID:

    autoread: :checktime failed for buffer 17: Vim:Lua callback:
    ...ed-95df8c0/share/nvim/runtime/lua/vim/lsp/completion.lua:1315: invalid client ID

Solution:
Use the completion augroup for `BufUnload` cleanup.

Problem: Argument type mismatches are excluded from EmmyLua checks.

Solution: Correct runtime annotations and calls, document local checker
workarounds, and enable the diagnostic.

AI-assisted

Problem:
Converting completion items reads 'completeopt' through vim.opt,
'ignorecase' and 'smartcase' for every item.

Solution:
Read them once per response.

Enable EmmyLua's assign-type-mismatch diagnostic after correcting the
runtime annotations and assignments it flags.

Correct option, tuple, and return types, and use separate locals when a
value changes representation. Add guards and narrow casts where needed
so the runtime passes the stricter check. Regenerate the affected docs.

AI-assisted