haskell_trial Install GHCup Need GHCup to use "Haskell for Visual Studio Code". https://marketplace.visualstudio.com/items?itemName=haskell.haskell For information on how to install GHCup, Please refer to the official sites. https://www.haskell.org/ghcup/install/ Projects helloworld This project tried the following: Executable Library Tests doctest hspec