/// <summary>
        /// Turn a query model into code.
        /// </summary>
        /// <param name="queryModel"></param>
        private void VisitQueryModelNoCache(QueryModel queryModel)
        {
            // Cache the referenced query expressions and restore them at the end.

            var cachedReferencedQS = _codeContext.GetAndResetQuerySourceLookups();

            // Protect against all returns...

            try
            {
                //
                // If the query model is something that is trivial, then
                // perhaps there is a short-cut we can take?
                //

                if (queryModel.IsIdentityQuery() && queryModel.ResultOperators.Count == 1)
                {
                    var ro        = queryModel.ResultOperators[0];
                    var processor = _operators.FindScalarROProcessor(ro.GetType());
                    if (processor != null)
                    {
                        var result = processor.ProcessIdentityQuery(ro, queryModel, _codeEnv, _codeContext, MEFContainer);
                        if (result != null &&
                            result.Item1)
                        {
                            Debug.WriteLine("Identity Query being processed");
                            _codeEnv.SetResult(result.Item2);
                            return;
                        }
                    }
                }

                // Have we seen this query model before? If so, perhaps we can just short-circuit this?

                var cachedResult = _codeContext.GetReplacement(queryModel);
                if (cachedResult != null)
                {
                    var context = _codeEnv.FirstAllInScopeFromNow(FindDeclarableParameters.FindAll(cachedResult));
                    if (context != null)
                    {
                        _codeEnv.SetResult(cachedResult);
                        return;
                    }
                }

                // If we drop through here, then let the full machinery parse the thing
                base.VisitQueryModel(queryModel);
            }
            finally
            {
                _codeContext.RestoreQuerySourceLookups(cachedReferencedQS);
            }
        }