Recent FPish FPish discussion focused on some hacks available in F# to write code that resembles using Haskell type classes. I particularly enjoyed the comments by Gustavo Leon and Loic Denuziere. To cut the long story short, before compiling to .NET F# expands methods delcared inline and does overload resolution. This was intended to support flexible operator overloading, but opens up the door for interesting hacks. Even code that generalizes over higher kinds and therefore cannot exist at .NET level [...]