Odditites regarding Any and typeclasses.

The typechecker seems to be unable to operate on contexts containing "naked" Any, for example:

x :: State [Any] ()
x = put []

    No instance for (MonadState [Any] (StateT [Any] Identity))
      arising from a use of ‘put’

A more minimal self-contained example would be:

{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances #-}
import GHC.Prim (Any)
class Class a b where method :: a -> b
instance Class a a where method = id
x :: Any -> Any
x = method

    No instance for (Class Any Any) arising from a use of ‘method’

It's quite obvious why this error happens (Any is not a datatype), however it also feels like it shouldn't happen. All of the above code seems to work in 7.8, which is back when Any was a datatype.

Trac metadata

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