Error message for accidentally using -> instead of =>

Consider the following typo:

sort :: Ord s -> [s] -> [s]
sort xs = Data.List.sort xs

GHC's error message in 7.10 is

    Expected a type, but ‘Ord s’ has kind ‘GHC.Prim.Constraint’
    In the type signature for ‘Main.sort’:
      Main.sort :: Ord s -> [s] -> [s]

I would suggest that mentioning kinds and GHC.Prim.Constraint is a bit unfriendly in a vanilla session (with ConstraintKinds etc switched off).

For comparison, the 6.12 error message was

    Class `Ord' used as a type
    In the type signature for `sort': sort :: Ord a -> [a] -> [a]

Trac metadata

Trac field	Value
Version	7.10.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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