Dear Cafe! I've encountered quite strange behaviour in GHC (v8.0.2) and I would like to ask you to give me a hint. Suppose we have the following functions: ---- foo :: (Show a) => Int -> a -> [String] foo n = replicate n . show bar :: Int -> (Show a) => a -> [String] bar n = replicate n . show baz :: Int -> a -> (Show a) => [String] baz n = replicate n . show ---- This won't compile, and that is ok. But if we add `RankNTypes` extension, this will compile and (:t) will give us the same signature for all three functions. There are two things I cannot get: 1) Why do this even compile? I saw constraints being defined either in the beginning of a signature or right after `forall` expression. I thought that it was a rule (or convention), but it's not. Is this way of declaring constraints (in the middle of a signature) discouraged or can be considered as a bug? 2) Even if this was supposed to be so, why was the constraint in `baz` hoisted to the top? There are at least two ways to interpret that signature: ---- baz :: Int -> a -> forall a. (Show a) => [String] baz :: forall a. (Show a) => Int -> a -> [String] ---- Is there any reason why the second one was chosen?