On Sat, Feb 13, 2016, at 01:04, Oliver Charles wrote:
Just a clarification - the presence of that parameter does not say "I use call stack" but rather "I need *a* call stack". This subtle difference means that you do need to know about this due to how stacks work in GHC. If you use error and then don't also add that constraint yourself to your function, youll only see part of the stack. Hence it more than just UX noise - I have a decision to make, and building a call stack gas a cost.
Also, is this RC2? I thought this was now changed to use constraint kinds and type alias the implicit parameter behind a nicer API.
Yes, RC2 still infers implicit parameter constraints as opposed to HasCallStack constraints. This is a bug, and it should be a simple fix. Eric