Exceptions, again... The docs for Control.Exception say (for Dynamic exceptions): "When using dynamic exceptions it is advisable to define a new datatype to use for your exception type, to avoid possible clashes with dynamic exceptions used in other libraries." So I went with that and created a datatype for my exceptions:

data MyException = MkExc Int String

... but now it seems I have to install this as an instance of Typeable, and I don't see how to do that.

instance Typeable MyException where typeOf ? = ?

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