GHC’s support for compiling multiple units in a single invocation is essential for tooling to work well with real-world Haskell projects. Loading your whole project into a single GHCi session allows you to get feedback quickly on changes to any part of your project, without having to restart the REPL. Until now, not all of GHCi worked with multiple home units, and this was a source of confusion for many users.
We’re now happy to announce that in 9.14.1, GHCi will fully support multiple home units. This post contains a brief overview of the changes.