[Haskell-cafe] Question on kind inference

Vladimir Reshetnikov v.reshetnikov at gmail.com
Sun May 31 03:17:17 EDT 2009


Consider this Haskell code:

class A a where
  foo :: a b

class B a

class (A a, B a) => C a

GHC compiles it without errors, but Hugs rejects it: "Illegal type in
class constraint".
What is the correct behavior, and which part of the haskell 98 report
explains this?


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