Example of vinyl subtyping.

mdedetrichModel.hs

{-# LANGUAGE DataKinds, FlexibleContexts, TypeOperators #-}
import Data.Vinyl

type Model = "model" ::: String

model :: Model
model = Field

type Car = PlainRec ["company":::String, Model, "year":::Int]

showModel :: (i <: PlainRec '[Model]) => i -> IO ()
showModel = putStrLn . rmodel . cast
  where rmodel :: PlainRec '[Model] -> String
        rmodel = rGet model

test :: IO ()
test = showModel car
  where car :: Car
        car = Field =: "Ford" <+> Field =: "Fusion" <+> Field =: 2013