Re: [Haskell-cafe] Ensuring all values of an ADT are explicitly handled OR finding all occurrences of type X in my app

On 01/30/2017 09:47 PM, Saurabh Nanda wrote:

Hi,

If I have the following ADT

data BookingState = Confirmed | Cancelled

which had a very high chance of being expanded in the future to have more values. How do I ensure that every pattern match on BookingState matches each value explicitly. Basically prevent the '_' matcher ?

Don't write the "_" case? GHC will warn you about any pattern matches you've missed.