private static Expression HandleGroup(
            EntityQueryModelVisitor entityQueryModelVisitor,
            GroupResultOperator groupResultOperator,
            QueryModel queryModel)
        {
            var keySelector
                = entityQueryModelVisitor
                  .ReplaceClauseReferences(
                      groupResultOperator.KeySelector,
                      queryModel.MainFromClause);

            var elementSelector
                = entityQueryModelVisitor
                  .ReplaceClauseReferences(
                      groupResultOperator.ElementSelector,
                      queryModel.MainFromClause);

            var expression
                = Expression.Call(
                      entityQueryModelVisitor.LinqOperatorProvider.GroupBy
                      .MakeGenericMethod(
                          entityQueryModelVisitor.Expression.Type.GetSequenceType(),
                          keySelector.Type,
                          elementSelector.Type),
                      entityQueryModelVisitor.Expression,
                      Expression.Lambda(keySelector, entityQueryModelVisitor.CurrentParameter),
                      Expression.Lambda(elementSelector, entityQueryModelVisitor.CurrentParameter));

            entityQueryModelVisitor.CurrentParameter
                = Expression.Parameter(expression.Type.GetSequenceType(), groupResultOperator.ItemName);

            entityQueryModelVisitor
            .AddOrUpdateMapping(groupResultOperator, entityQueryModelVisitor.CurrentParameter);

            return(expression);
        }
        private static Expression HandleGroup(
            EntityQueryModelVisitor entityQueryModelVisitor,
            GroupResultOperator groupResultOperator,
            QueryModel queryModel)
        {
            var keySelector
                = entityQueryModelVisitor
                    .ReplaceClauseReferences(
                        groupResultOperator.KeySelector,
                        queryModel.MainFromClause);

            var elementSelector
                = entityQueryModelVisitor
                    .ReplaceClauseReferences(
                        groupResultOperator.ElementSelector,
                        queryModel.MainFromClause);

            var expression
                = Expression.Call(
                    entityQueryModelVisitor.LinqOperatorProvider.GroupBy
                        .MakeGenericMethod(
                            entityQueryModelVisitor.Expression.Type.GetSequenceType(),
                            keySelector.Type,
                            elementSelector.Type),
                    entityQueryModelVisitor.Expression,
                    Expression.Lambda(keySelector, entityQueryModelVisitor.CurrentParameter),
                    Expression.Lambda(elementSelector, entityQueryModelVisitor.CurrentParameter));

            entityQueryModelVisitor.CurrentParameter
                = Expression.Parameter(expression.Type.GetSequenceType(), groupResultOperator.ItemName);

            entityQueryModelVisitor
                .AddOrUpdateMapping(groupResultOperator, entityQueryModelVisitor.CurrentParameter);

            return expression;
        }