Test GHC 8.2.1-rc3 with Stack. https://mail.haskell.org/pipermail/ghc-devs/2017-July/014364.html

stack.yaml

# https://mail.haskell.org/pipermail/ghc-devs/2017-July/014364.html
# https://downloads.haskell.org/~ghc/8.2.1-rc3/
# http://taylor.fausak.me/2017/05/17/testing-ghc-release-candidates-with-stack/
compiler: ghc-8.2.0.20170704
compiler-check: match-exact

resolver: ghc-8.2.0.20170704

setup-info:
  ghc:

    linux64:
      8.2.0.20170704:
        url: https://downloads.haskell.org/~ghc/8.2.1-rc3/ghc-8.2.0.20170704-x86_64-deb8-linux.tar.xz
        content-length: 138482820
        sha1: ac1598c21ea2936b091885a29a0f5725668aaed5

    macosx:
      8.2.0.20170704:
        url: https://downloads.haskell.org/~ghc/8.2.1-rc3/ghc-8.2.0.20170704-x86_64-apple-darwin.tar.xz
        content-length: 125197252
        sha1: 81e3093b559b9aaf8af2a89f182539849539cbe1

    windows64:
      8.2.0.20170704:
        url: https://downloads.haskell.org/~ghc/8.2.1-rc3/ghc-8.2.0.20170704-x86_64-unknown-mingw32.tar.xz
        content-length: 175463160
        sha1: 3648302c66769d4aa0c3a9f82be4538f402f234f

It's far more convenient to use nightly resolver: resolver: nightly-2017-07-19 and set allow-newer: true.

Be sure then to use (due to haskell/deepseq#34):

- location:
    git: https://github.com/haskell/deepseq.git
    commit: 0b22c9825ef79c1ee41d2f19e7c997f5cdc93494
  extra-dep: true