type holes related ghc panic

sample.hs:9:13:
    Couldn't match expected type ‘t’ with actual type ‘()’
      ‘t’ is untouchable
        inside the constraints ()
        bound by the inferred type of foo :: Meta -> t1
        at sample.hs:(6,1)-(9,17)ghc: panic! (the 'impossible' happened)
  (GHC version 7.10.0.0 for x86_64-unknown-linux):
        No skolem info: t_avJ[sk]

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


sample.hs:
module Blah where

newtype Meta = Meta ()

foo (Meta ws1) =
    let copy :: _
        copy w from = copy w 1
    in copy ws1 1

Trac metadata

Trac field	Value
Version	7.10.1-rc2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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