Almost all Haskell code written these days uses at least a handful, if not a barrel-full, of extensions, and ScopedTypeVariables is one of the most common ones.

Almost all Haskell code written these days uses at least a handful, if not a barrel-full, of extensions, and ScopedTypeVariables is one of the most common ones. Of course, you’re completely free to do whatever you’d like with your own code, but you’ll probably find it hard to avoid extensions — at the least many of them will be used by some libraries you’re depending on.