Am Samstag, den 12.05.2018, 16:41 -0400 schrieb Gershom B:
There is an important change in the cabal new- commands for 2.2 that the release docs should have highlighted more significantly.
Cabal new-* commands now produce a .ghc.environment file by default. These files [1] are picked up by ghc and ghci automatically (since 8.0.1), and allow them to operate directly with the same package environment used by the new-* commands. This lets you, for example, run `ghci` in a project where you are using `new-build` and get the proper dependencies in scope. Herbert has written an experimental tool to make it easier to create and manipulate these environments [2].
I already had issues with this. I ran some custom tool, which was a Haskell script, in a directory where I had run cabal new-build before. As a result, this tool didn’t work, because some module it needed couldn’t be found. It took me a while to find out what the problem was. In my opinion, it is questionable that these GHC environment files are generated by cabal new-build and then influence even Haskell scripts that have nothing to do with the project at hand. All the best, Wolfgang