2 files changed, 15 insertions, 13 deletions
diff --git a/runtime/lua/vim/lsp.lua b/runtime/lua/vim/lsp.lua
index 3d3c856fcb..f3ee484024 100644
--- a/runtime/lua/vim/lsp.lua
+++ b/runtime/lua/vim/lsp.lua
@@ -1531,9 +1531,14 @@ function lsp.start_client(config)
       pcall(config.on_attach, client, bufnr)
     end
 
-    if vim.tbl_get(client.server_capabilities, 'semanticTokensProvider', 'full') then
-      semantic_tokens.start(bufnr, client.id)
-    end
+    -- schedule the initialization of semantic tokens to give the above
+    -- on_attach and LspAttach callbacks the ability to schedule wrap the
+    -- opt-out (deleting the semanticTokensProvider from capabilities)
+    vim.schedule(function()
+      if vim.tbl_get(client.server_capabilities, 'semanticTokensProvider', 'full') then
+        semantic_tokens.start(bufnr, client.id)
+      end
+    end)
 
     client.attached_buffers[bufnr] = true
   end
diff --git a/runtime/lua/vim/lsp/semantic_tokens.lua b/runtime/lua/vim/lsp/semantic_tokens.lua
index 99cdc20f54..66e656abb6 100644
--- a/runtime/lua/vim/lsp/semantic_tokens.lua
+++ b/runtime/lua/vim/lsp/semantic_tokens.lua
@@ -313,18 +313,15 @@ function STHighlighter:process_response(response, client, version)
       return a.start < b.start
     end)
 
-    ---@private
-    local function _splice(list, start, remove_count, data)
-      local ret = vim.list_slice(list, 1, start)
-      vim.list_extend(ret, data)
-      vim.list_extend(ret, list, start + remove_count + 1)
-      return ret
-    end
-
-    tokens = state.current_result.tokens
+    tokens = {}
+    local old_tokens = state.current_result.tokens
+    local idx = 1
     for _, token_edit in ipairs(token_edits) do
-      tokens = _splice(tokens, token_edit.start, token_edit.deleteCount, token_edit.data)
+      vim.list_extend(tokens, old_tokens, idx, token_edit.start)
+      vim.list_extend(tokens, token_edit.data)
+      idx = token_edit.start + token_edit.deleteCount + 1
     end
+    vim.list_extend(tokens, old_tokens, idx)
   else
     tokens = response.data
   end