anchor.diff:  let read_interactive_query stream : query =
     try
       match Util.read_line stream with
  -    | None -> exit 0
  +    | None -> raise (ExitREPL 0)
       | Some line ->
         match Util.json_of_string line with
         | None -> { qid = "?"; qq = ProtocolViolation "Json parsing failed." }
  
positive.code: module DsEnv = FStar.ToSyntax.Env
  module TcEnv = FStar.TypeChecker.Env
  module CTable = FStar.Interactive.CompletionTable
  
  // A custom version of the function that's in FStar.Universal.fs just for the
  // sake of the interactive mode
  
negative.code:           { qid = q.qid; qq = MissingCurrentModule }
          | _ -> q
  
  let rec go st : int =
    let rec loop st : int =
      let query = validate_query st (read_interactive_query st.repl_stdin) in
      let (status, response), state_opt = run_query st query.qq in
      write_response query.qid status response;
      match state_opt with
      | Inl st' -> loop st'
      | Inr exitcode -> raise (ExitREPL exitcode) in
  
    if Options.trace_error () then
      loop st
    else
      try loop st with ExitREPL n -> n
  
  let interactive_error_handler = // No printing here — collect everything for future use
    let issues : ref<list<issue>> = Util.mk_ref [] in
  