defeffect functions return a different type than the one handle/1 expects

[rosacris]

Hi,

I've been trying to experiment with the library but I'm stuck with an issue that it can be easily spotted in the documentation:

# Create the computation. 
computation = MessageApp.greet "Fred" 
# Perform the computation. 
MessageInterpreter.Console.handle(computation)

The typespec of computation is MessageEffect.t, however the typespec of MessageInterpreter.Console.handle/1 is MessageEffect.Say.e

When I try to run a minimal example it fails exactly for this reason.