Deriving Read of an empty datatype crashes

Standalone deriving Read of an empty datatype crashes:

{-# LANGUAGE StandaloneDeriving #-}
data A
deriving instance Read A

ghc: panic! (the 'impossible' happened)
  (GHC version 7.7.20130515 for x86_64-unknown-linux):
	Prelude.foldr1: empty list

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

(Oddly, the "panic" message is given only by ghc, not ghci, but this is minor.)

While the Read instance seems to be of little use, it can be used for reading types such as Either Void Int.

Patch attached.

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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Deriving Read of an empty datatype crashes