4 files changed, 36 insertions, 20 deletions
diff --git a/runtime/lua/vim/lsp/protocol.lua b/runtime/lua/vim/lsp/protocol.lua
index 2773f59b45..70862320c5 100644
--- a/runtime/lua/vim/lsp/protocol.lua
+++ b/runtime/lua/vim/lsp/protocol.lua
@@ -632,15 +632,18 @@ function protocol.make_client_capabilities()
 
         codeActionLiteralSupport = {
           codeActionKind = {
-            valueSet = {};
+            valueSet = vim.tbl_values(protocol.CodeActionKind);
           };
         };
       };
       completion = {
         dynamicRegistration = false;
         completionItem = {
+          -- Until we can actually expand snippet, move cursor and allow for true snippet experience,
+          -- this should be disabled out of the box.
+          -- However, users can turn this back on if they have a snippet plugin.
+          snippetSupport = false;
 
-          snippetSupport = true;
           commitCharactersSupport = false;
           preselectSupport = false;
           deprecatedSupport = false;
@@ -940,11 +943,9 @@ function protocol.resolve_capabilities(server_capabilities)
 
   if server_capabilities.codeActionProvider == nil then
     general_properties.code_action = false
-  elseif type(server_capabilities.codeActionProvider) == 'boolean' then
+  elseif type(server_capabilities.codeActionProvider) == 'boolean'
+    or type(server_capabilities.codeActionProvider) == 'table' then
     general_properties.code_action = server_capabilities.codeActionProvider
-  elseif type(server_capabilities.codeActionProvider) == 'table' then
-    -- TODO(ashkan) support CodeActionKind
-    general_properties.code_action = false
   else
     error("The server sent invalid codeActionProvider")
   end
diff --git a/runtime/lua/vim/lsp/rpc.lua b/runtime/lua/vim/lsp/rpc.lua
index 749a51fecc..17c411f952 100644
--- a/runtime/lua/vim/lsp/rpc.lua
+++ b/runtime/lua/vim/lsp/rpc.lua
@@ -42,13 +42,28 @@ local function is_dir(filename)
 end
 
 local NIL = vim.NIL
+
+--@private
+local recursive_convert_NIL
+recursive_convert_NIL = function(v, tbl_processed)
+  if v == NIL then
+    return nil
+  elseif not tbl_processed[v] and type(v) == 'table' then
+    tbl_processed[v] = true
+    return vim.tbl_map(function(x)
+      return recursive_convert_NIL(x, tbl_processed)
+    end, v)
+  end
+
+  return v
+end
+
 --@private
 --- Returns its argument, but converts `vim.NIL` to Lua `nil`.
 --@param v (any) Argument
 --@returns (any)
 local function convert_NIL(v)
-  if v == NIL then return nil end
-  return v
+  return recursive_convert_NIL(v, {})
 end
 
 --@private
diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index 775932c7fd..9ed19b938d 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -214,13 +214,16 @@ end
 function M.apply_text_document_edit(text_document_edit)
   local text_document = text_document_edit.textDocument
   local bufnr = vim.uri_to_bufnr(text_document.uri)
-  if text_document.version then
-    -- `VersionedTextDocumentIdentifier`s version may be null https://microsoft.github.io/language-server-protocol/specification#versionedTextDocumentIdentifier
-    if text_document.version ~= vim.NIL and M.buf_versions[bufnr] ~= nil and M.buf_versions[bufnr] > text_document.version then
-      print("Buffer ", text_document.uri, " newer than edits.")
-      return
-    end
+
+  -- `VersionedTextDocumentIdentifier`s version may be null
+  --  https://microsoft.github.io/language-server-protocol/specification#versionedTextDocumentIdentifier
+  if text_document.version
+      and M.buf_versions[bufnr]
+      and M.buf_versions[bufnr] > text_document.version then
+    print("Buffer ", text_document.uri, " newer than edits.")
+    return
   end
+
   M.apply_text_edits(text_document_edit.edits, bufnr)
 end
 
@@ -492,10 +495,7 @@ function M.convert_signature_help_to_markdown_lines(signature_help)
   --=== 0`. Whenever possible implementors should make an active decision about
   --the active signature and shouldn't rely on a default value.
   local contents = {}
-  local active_signature = signature_help.activeSignature
-  if active_signature == vim.NIL or active_signature == nil then
-    active_signature = 0
-  end
+  local active_signature = signature_help.activeSignature or 0
   -- If the activeSignature is not inside the valid range, then clip it.
   if active_signature >= #signature_help.signatures then
     active_signature = 0
@@ -535,7 +535,7 @@ function M.convert_signature_help_to_markdown_lines(signature_help)
       }
       --]=]
       -- TODO highlight parameter
-      if parameter.documentation and parameter.documentation ~= vim.NIL then
+      if parameter.documentation then
         M.convert_input_to_markdown_lines(parameter.documentation, contents)
       end
     end
diff --git a/runtime/lua/vim/treesitter/highlighter.lua b/runtime/lua/vim/treesitter/highlighter.lua
index decde08019..6714bb6354 100644
--- a/runtime/lua/vim/treesitter/highlighter.lua
+++ b/runtime/lua/vim/treesitter/highlighter.lua
@@ -157,7 +157,7 @@ local function on_line_impl(self, buf, line)
       a.nvim_buf_set_extmark(buf, ns, start_row, start_col,
                              { end_line = end_row, end_col = end_col,
                                hl_group = hl,
-                               ephemeral = true
+                               ephemeral = true,
                               })
     end
     if start_row > line then