We officially support GHC 8.6+ (and 8.8+ for hledger-web) now.
Hackage matrix builder shows all packages building successfully
with GHC 8.4+, somehow, so we'll adjust the base bound to
allow that but prevent any attempts to build with older GHCs,
Prior to this commit,
- hledger still builds with GHC 8.0
- hledger-ui does if you use the build plan specified by stack8.0.yaml,
but you are likely to hit problems if you let cabal pick one
(https://github.com/jtdaugherty/vty/issues/198 and others)
- hledger-web might, if you could find the right build plan
The hassles are enough and GHC 8.0 is old enough (first released in
2016) that I'm letting it go; 8.2 is the new minimum version for all
hledger packages.
This allows a bunch of cleanups to conditional imports, which I leave
for later.
Also, updated the tested-with minor versions.
in JournalReader.hs. If you still need this, feel free to work on
those errors. But hopefully not, because dropping base 4.8 should
permit some code cleanups.
fail is moving out of Monad and into it's own MonadFail class.
This will be enforced in GHC 8.8 (I think).
base-compat/base-compat-batteries 0.11.0 have adapted to this,
and are approaching stackage nightly
(https://github.com/commercialhaskell/stackage/issues/4802).
hledger is now ready to build with base-compat-batteries 0.11.0, once
all of our deps do (eg aeson). We are still compatible with the older
0.10.x and GHC 7.10.3 as well.
For now we are using both fails:
- new fail (from Control.Monad.Fail), used in our parsers, imported
via base-compat-batteries Control.Monad.Fail.Compat to work with
older GHC versions.
- old fail (from GHC.Base, exported by Prelude, Control.Monad,
Control.Monad.State.Strict, Prelude.Compat, ...), used in easytest's
Test, since I couldn't find their existing fail implementation to update.
To reduce (my) confusion, these are imported carefully, consistently,
and qualified everywhere as Fail.fail and Prelude.fail, with clashing
re-exports suppressed, like so:
import Prelude hiding (fail)
import qualified Prelude (fail)
import Control.Monad.State.Strict hiding (fail)
import "base-compat-batteries" Prelude.Compat hiding (fail)
import qualified "base-compat-batteries" Control.Monad.Fail.Compat as Fail
