":show modules" Panic

While working exercises in "Haskell Road to Logic, Maths", I got this message in response to a :show modules" command:

    Prelude> :show modules
    SetEq            ( SetEq.hs, interpreted )
    : panic! (the 'impossible' happened)
      (GHC version 6.6 for i386-unknown-mingw32):
            missing linkable
    
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Edited Mar 09, 2019 by Ian Lynagh -

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information