Broken types in identifiers bound by :print

GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
Prelude> :print show
show = (_t1::Show a => a -> String)
Prelude> :t _t1

<interactive>:1:1: error:
    No instance for (Show a) arising from a use of ‘it’

Furthermore:

Prelude> _t1 "foo"

<interactive>:3:5: error:ghc: panic! (the 'impossible' happened)
  (GHC version 8.0.1 for x86_64-unknown-linux):
	No skolem info: a_a1hz

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Prelude> 

Enabling -fprint-explicit-foralls, I think, reveals the issue:

Prelude> :set -fprint-explicit-foralls 
Prelude> :print id
id = (_t2::a1 -> a1)
Prelude> :t id
id :: forall {a}. a -> a
Prelude> :t _t2
_t2 :: a1 -> a1

Similar behavior albeit with a different panic message happens on 7.8.4 and 7.10.3 as verified by bennofs over IRC:

GHCi, version 7.10.3: http://www.haskell.org/ghc/  :? for help
Prelude> :print print
print = (_t1::Show a => a -> IO ())
Prelude> _t1
ghc: panic! (the 'impossible' happened)
  (GHC version 7.10.3 for x86_64-unknown-linux):
	tcTyVarDetails a_apc

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

1. 6.3 doesn't exhibit this issue:

GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help
Prelude> :print id
id = (_t1::forall a. a -> a)

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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