Fix the nil bug and add the request->handler to the queue

Author: scottming

apps/language_server/lib/language_server/experimental/provider/handlers/goto_definition.ex

@@ -5,6 +5,7 @@ defmodule ElixirLS.LanguageServer.Experimental.Provider.Handlers.GotoDefinition
   alias ElixirLS.LanguageServer.Experimental.Protocol.Types.Range, as: LSRange
   alias ElixirLS.LanguageServer.Experimental.SourceFile
   alias ElixirLS.LanguageServer.Experimental.SourceFile.Conversions
+  require Logger
 
   def handle(%GotoDefinition{} = request, _) do
     source_file = request.source_file
@@ -18,9 +19,10 @@ defmodule ElixirLS.LanguageServer.Experimental.Provider.Handlers.GotoDefinition
       {:reply, Responses.GotoDefinition.new(request.id, definition)}
     else
       nil ->
-        {:reply, nil}
+        {:reply, Responses.GotoDefinition.new(request.id, nil)}
 
       {:error, reason} ->
+        Logger.error("GotoDefinition failed: #{inspect(reason)}")
         {:error, Responses.GotoDefinition.error(request.id, :request_failed, reason)}
     end
   end

apps/language_server/lib/language_server/experimental/provider/queue.ex

@@ -15,7 +15,8 @@ defmodule ElixirLS.LanguageServer.Experimental.Provider.Queue do
     @requests_to_handler %{
       Requests.FindReferences => Handlers.FindReferences,
       Requests.Formatting => Handlers.Formatting,
-      Requests.CodeAction => Handlers.CodeAction
+      Requests.CodeAction => Handlers.CodeAction,
+      Requests.GotoDefinition => Handlers.GotoDefinition
     }
 
     def new do