[dllthomas]

Lots of typeclasses have associated "laws" that well-behaved instances are expected to abide by.

[laureny]

But these are not enforceable by the type system (at least in Haskell), kind of supporting my point that types alone are rarely sufficient :)

[dllthomas]

I don't think anyone believes that types are sufficient outside, at least outside of a dependently typed language (at which point you'll have more diversity of opinion).

[tel]

Types in Haskell won't buy you 100% of what you need, but they may buy you 50%.