List constructor names of a Haskell type?

conNameOf allows me to display the constructor name of a given piece of data, given that type is an instance of Generic.

What I'd like is something similar. For a given type, I want to get the full list of constructor names. For example:

data Nat = Z | S Nat
  deriving (Generic)

-- constrNames (Proxy :: Proxy Nat) == ["Z", "S"]

Does something like constrNames exist? If not, how can I write it?