A 10x Speedup in GHCi

Many of us at Supercede use GHCi directly when developing Haskell projects. It runs the local development server, and the automated test suite, and serves as a scratch pad for ad hoc expression evaluation and type inspection. We make heavy use of integrated tests with the yesod-test framework. One of our projects now has more than 500 tests. Running the tests in GHCi takes about 150 seconds. Not…