Yeah, exception resolution is pretty weird in Haskell due to laziness. In some sense, you end up thinking of exceptions as being buried in values in the languag

Yeah, exception resolution is pretty weird in Haskell due to laziness. In some sense, you end up thinking of exceptions as being buried in values in the language instead of exposed by computation—this is your null-value landmine problem exactly http://research.microsoft.com/en-us/um/people/simonpj/papers/imprecise-exn.htm http://research.microsoft.com/en-us/um/people/simonpj/papers... This is also why the Control.Exception module exposes `evaluate`, which embeds a value in an IO computation and thus resolves this problem... If you remember to use it. http://hackage.haskell.org/package/base-4.7.0.0/docs/Control-Exception.html#g:8 http://hackage.haskell.org/package/base-4.7.0.0/docs/Control... Fortunately, in idiomatic Haskell exceptions are considered to be an expert feature (basically I see them in concurrent IO or resource management code only) and partial functions—usually introduced by incomplete pattern matching like `None.get` does—are veboten. It's not perfect, but -Wall will help with that.