I did not say it was impossible to write Haskell with bugs. I simply stated that you are not guaranteed that a particular implementation of a design pattern adh

I did not say it was impossible to write Haskell with bugs. I simply stated that you are not guaranteed that a particular implementation of a design pattern adheres to the patterns semantics, therefore introducing a bug. With good usage of Haskell's type system, you can wholly avoid such bugs, and a great example of this, as I stated, is the associativity laws within the pipes library. Semantics! :)