Fair point. I realise I sound quite critical in my comments so perhaps I should add that I like the tool itself. The problems that I see are more in the usage a

Fair point. I realise I sound quite critical in my comments so perhaps I should add that I like the tool itself. The problems that I see are more in the usage as shown in the examples. I am not necessarily suggesting that in all circumstances, the most general types are the best. But I am yet to see this tool used in such a way as to permit the most general types, as would be appropriate for library functions.