Derived DataKinds Typeable instance collision leads to SafeHaskell violation

The derived Typeable instances for a kind (with DataKinds) is equal to the instance of a type with the same name:

λ> data T = T
λ> typeRep (Proxy :: Proxy T) == typeRep (Proxy :: Proxy 'T)
True

This can be used to violate SafeHaskell easily:

{-# LANGUAGE AutoDeriveTypeable, DataKinds, TypeFamilies, RankNTypes #-}

module Unsafe where

import Data.Typeable

data T = T

data family F p

newtype instance F (Proxy  T) = ID (forall a. a -> a)
newtype instance F (Proxy 'T) = UC (forall a b. a -> b)

uc :: a -> b
uc = case cast (ID id) of Just (UC f) -> f

$ ghc -XSafe Unsafe.hs -e "uc 'a' :: Int"
97

Trac metadata

Trac field	Value
Version	7.8.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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