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(parent: 79a6f3f) | patch
-XImpredicativeTypes implies -XRankNTypes, and improve error msg in TcMType
authorsimonpj@microsoft.com <unknown>
Wed, 31 Dec 2008 15:25:17 +0000 (15:25 +0000)
committersimonpj@microsoft.com <unknown>
Wed, 31 Dec 2008 15:25:17 +0000 (15:25 +0000)
commit2d9c6a02b4bc2c2561d627eac4029ad8aa03c751
tree332630df5c74e83e789451bfae577b4705ecc0c3tree | snapshot
parent79a6f3fa318020567566f92740ba6b9eb542f73fcommit | diff
-XImpredicativeTypes implies -XRankNTypes, and improve error msg in TcMType

If you are going for impredicative types you almost certainly want RankN
too. The change to TcMType improves the error when you say
     T (forall a. blah)
where T is a type synonym.  This doesn't necessarily need impredicativity,
if you have LiberalTypeSynonyms.
compiler/main/DynFlags.hs diff | blob | history
compiler/typecheck/TcMType.lhs diff | blob | history
Glasgow Haskell Compiler with heterogeneous metaprogramming (generalized arrows and modal types)