I've put together a [https://github.com/deech/Trac12506 reduced example]
#12506: Compile time regression in GHC 8. -------------------------------------+------------------------------------- Reporter: deech | Owner: bgamari Type: bug | Status: new Priority: high | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by tdammers): Replying to [comment:16 deech]: that has the same issues. It's much easier to work with. In putting this together I noticed there is a vast difference in compilation time and memory between GHC 8.02 and GHC 8.22; the former takes 45 seconds and uses 1.4GB RAM to compile, the latter, 10 seconds and 200 MB so that is a great improvement.
However while compilation speed is much improved between 8.0.2 and 8.2.2
that still only brings it up to par with GHC 7.10 which is GHC version against which I reported the issue in the first place so the problem still exists.
Hopefully this reduced example helps clarify the underlying issue.
Great, that makes things so much easier! Thanks a lot, I'll look into it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12506#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler