feat(lsp): apply additionalTextEdits on completion accept

lua/lsp/completion/popup.lua

@@ -22,42 +22,23 @@ local function fence(ft, text)
     return string.format("```%s\n%s\n```", ft, text)
 end
 
----@param item lsp.CompletionItem
----@return string
-local function signature_of(item)
-    return item.detail or vim.tbl_get(item, "labelDetails", "description") or ""
-end
-
 ---@param item lsp.CompletionItem
 ---@param ft string
 ---@return string? content
 ---@return integer? width
 local function build_content(item, ft)
-    local signature = signature_of(item)
+    local signature = item.detail
+        or vim.tbl_get(item, "labelDetails", "description")
     local doc = item.documentation
     if type(doc) == "table" then
         doc = doc.value
     end
-    doc = doc or ""
-
-    local code_parts = {}
-    if item.additionalTextEdits then
-        for _, edit in ipairs(item.additionalTextEdits) do
-            local text = (edit.newText or ""):gsub("%s+$", "")
-            if text ~= "" then
-                table.insert(code_parts, fence(ft, text))
-            end
-        end
-    end
-    if signature ~= "" then
-        table.insert(code_parts, fence(ft, signature))
-    end
 
     local sections = {}
-    if #code_parts > 0 then
-        table.insert(sections, table.concat(code_parts, "\n\n"))
+    if signature then
+        table.insert(sections, fence(ft, signature))
     end
-    if doc ~= "" then
+    if doc then
         table.insert(sections, doc)
     end
     if #sections == 0 then
@@ -78,6 +59,7 @@ end
 ---@field private winid integer?
 ---@field private bufnr integer?
 ---@field private pending ow.lsp.completion.PendingResolve?
+---@field private resolved { word: string, item: lsp.CompletionItem }?
 local Popup = {}
 Popup.__index = Popup
 
@@ -87,9 +69,23 @@ function Popup.new()
         winid = nil,
         bufnr = nil,
         pending = nil,
+        resolved = nil,
     }, Popup)
 end
 
+--- Most recently resolved completion item for the given selection `word`,
+--- or `nil` if we don't have one cached. Servers like rust-analyzer fill in
+--- `additionalTextEdits` only in the resolve response, so on accept we want
+--- the resolved version rather than the original one in `user_data`.
+---@param word string
+---@return lsp.CompletionItem?
+function Popup:resolved_for(word)
+    if self.resolved and self.resolved.word == word then
+        return self.resolved.item
+    end
+    return nil
+end
+
 ---@return boolean
 function Popup:is_visible()
     return self.winid ~= nil and vim.api.nvim_win_is_valid(self.winid)
@@ -127,6 +123,7 @@ end
 ---@param buf integer
 function Popup:dispatch_resolve(client, item, ft, pum, word, buf)
     self:cancel_pending()
+    self.resolved = nil
     local _, request_id = client:request(
         vim.lsp.protocol.Methods.completionItem_resolve,
         item,
@@ -139,6 +136,7 @@ function Popup:dispatch_resolve(client, item, ft, pum, word, buf)
             if (vim.tbl_get(cur, "completed", "word") or "") ~= word then
                 return
             end
+            self.resolved = { word = word, item = result }
             self:show(result, ft, pum)
         end,
         buf