* Use cabal-doctest
- Haskell build tools run in slightly different environments (meaning different
package databases are available).
- The nixpkgs build for polysemy-plugin is failing due to a missing package
database, which causes the doctest to fail (more information here:
https://github.com/NixOS/nixpkgs/issues/71164).
- By using cabal-doctest we can expose the Haskell packages required to the
doctests no matter the build tool we're using.
* Use cabal-doctest in polysemy, build on GHC 8.8.1
- Use @googleson78 's changes to build polysemy on GHC 8.8.1, with slight
modifications. The source distribution is now found in "dist-newstyle/sdist",
so we've updated the command to point at that folder. Additionally, cabal
v2-install doesn't support installing .tar.gz files in the same way v1-install
did, so updated the command to use "cabal v1-install".
- Modified polysemy to use "cabal-doctest" and so overcome issues with the
doctest tests (see issue #258, PR #265).
Turns out haddocks have been broken forever, but because of haskell/cabal#5977 we never noticed. This PR fixes CI so it breaks (see 6f915b6), and then fixes it by changing the GHC versions under which we're allowed to use loopbreaker. Fixes#160
The travis cache appears to be broken (probably due to the nightly stack?), but it just means CI takes like half an hour now. Since I already build on stack, I'm pretty sure it's fine --- also this will give a sanity check against accidentally breaking cabal build plans.
This improves CI times from ~30 minutes down to ~2.
This PR removes some things in the travis CI that I cargo culted and
didn't understand but am reasonably sure don't do anything except slow
down CI times.
