On 22/10/2012 19:15, Ashley Yakeley wrote:

On 22.10.2012 11:05, Johan Tibell wrote:

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I think it's OK if a compiler accepts a program incorrectly marked "Rank2Types" when it actually requires rank-n types?

It's an interesting question: does Rank2Types mean "I require at least rank-2 types" or "I only use rank-2 types"?

I think it means "I require at least rank-2 types".

To clarify, I think it's OK if a compiler accepts a program marked "Rank2Types" and incorrectly not marked "RankNTypes" when it actually requires rank-n types.

I don't think I understand why you would want an extension flag to mean "at least" rather than "at most". No other extension flag works that way. If you take that view to its logical conclusion, we would never need to specify any extension flags at all. Rank2Types is only useful if it really means rank-2 types, which it apparently doesn't, so I'm quite happy to deprecate it. We don't have to actually remove it for a long time, since the cost of maintaining one flag that is a synonym for another flag is small. Cheers, Simon