Feature Requestgood first issue
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描述
Phantom types are very useful for tagging things on type level, but at the moment this code will not compile
-- @Employment.hs
{-# LANGUAGE TemplateHaskell #-}
module Employment where
import Database.Persist.TH
import Prelude
data Employment a = Employed | Unemployed | Retired
deriving (Show, Read, Eq)
derivePersistField "Employment a"