On 09/06/2015 23:26, Johan Tibell wrote:
Thanks for putting this together.
The proposal says:
"As a consequence, in current Haskell, you can not use Monad-polymorphic code safely, because although it claims to work for all Monads, it might just crash on you. This kind of implicit non-totality baked into the class is terrible."
Is this actually a problem in practice? Is there any code we can point to that suffers because of the current state of affairs? Could it be included in the proposal?
Here's a concrete example: https://mail.haskell.org/pipermail/libraries/2015-March/025166.html I needed to change some code that used a monad with an explicit fail to use one without, and I couldn't get the compiler to tell me if it was using partial pattern matches or not. If it had been then the refactoring would have caused a nasty behaviour change. Ganesh