src/Pure/Tools/server_commands.scala

         Args(session, prefs = prefs, opts = opts, dirs = dirs, ancestor_session = ancestor_session,
           all_known = all_known, focus_session = focus_session, required_session = required_session,
           system_mode = system_mode, verbose = verbose)
       }
 
-    def command(progress: Progress, args: Args): (JSON.T, Build.Results, Sessions.Base_Info) =
+    def command(progress: Progress, args: Args)
+      : (JSON.Object.T, Build.Results, Sessions.Base_Info) =
     {
       val options = Options.init(prefs = args.prefs, opts = args.opts)
       val dirs = args.dirs.map(Path.explode(_))
 
       val base_info =