> 1. type classes in Haskell are supposedly coherent, i.e. the compiler is supposed to force a single type class instance in the whole project, however GHC does

> 1. type classes in Haskell are supposedly coherent, i.e. the compiler is supposed to force a single type class instance in the whole project, however GHC does in fact not do that so you can end up with multiple instances of the same type in the same project Can you give an example?