Loosen the rules for instance declarations (Part 3)
authorRoss Paterson <ross@soi.city.ac.uk>
Mon, 13 Feb 2006 16:10:44 +0000 (16:10 +0000)
committerRoss Paterson <ross@soi.city.ac.uk>
Mon, 13 Feb 2006 16:10:44 +0000 (16:10 +0000)
commit8e512635b618e1daa97022265f268ad4eafda6b4
tree495a9fdef7b2d33f17764a1d71433b08a28605bc
parente68a5b608d7ac55f133481d9e428119850668e7a
Loosen the rules for instance declarations (Part 3)

Relax the restrictions on derived instances in the same way, so we
can write

data MinHeap h a = H a (h a) deriving (Show)
ghc/compiler/typecheck/TcDeriv.lhs
ghc/compiler/typecheck/TcMType.lhs
ghc/compiler/typecheck/TcSimplify.lhs
ghc/docs/users_guide/glasgow_exts.xml