On 05/07/12 17:18, rickmurphy wrote:
Hi All:
I've been working through some details in these papers [1], [2] and
noticed a language pragma configuration that I hope you can confirm.
When using explicit foralls in a data constructor, it appears that GHC
7.4.2 requires Rank2Types in the Language pragma for what the papers
consider rank 1 types.
Here's an example:
data T = TC (forall a b. a -> b -> a)
Am I correct, or is there another extension? The ExplicitForAll does not
appear to support rank 1 types in data constructors.
There is the PolymorphicComponents extension precisely for this use case.
Twan
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