Support transformers-0.6

[andreasabel]

Support transformers-0.6

[RyanGlScott]

Thanks! I've uploaded free-5.1.8 to Hackage with a fix.

[RyanGlScott]

At the moment, this is waiting on a new release of mtl that supports transformers-0.6. Since it appears that a new mtl release may be happening soon, I'll wait to see how that shakes out. In the meantime, I have an experimental mtl-2.3 branch that will likely serve your needs in the interim.

[emilypi]

Just to bump this, mtl-2.3 has been released, and free looks good to go to bump the dep:

  -- GHC-7.8 bundles transformers-0.3,
  -- mtl-2.2.* requires transformers >=0.4
  -- mtl-2.3.* requires base >=4.12
  if impl(ghc >=7.10)
    build-depends:
      mtl               >= 2.2.2 && < 2.4

This builds fine on my machine