Compiling executable using servant-0.12 takes a very long time

I have a pretty large server built on servant, somewhere around 100-120 routes. It was originally built on servant 4 and upgraded to servant 9. I recently made an attempt to upgrade to servant-0.12 and noticed it takes a very long time to compile (over 20 minutes). My server builds in under 10 minutes using servant-0.9 and servant-0.11, using stack with lts-9.17.

For some reason, servant-0.12 takes a long time at the very end of the build when compiling the server executable. This doesn't happen with stack repl, so presumably its the linking step.

I also noticed this occurs with servant-0.11 using a nightly stackage snapshot (resolver: nightly-2017-12-01), which is using ghc 8.2.2