ip1.hs

{-# LANGUAGE GADTs, ConstraintKinds, Rank2Types, ImplicitParams #-}

data Rec fields where
  Rec :: fields => Rec fields

infixr 1 ?
(?) :: Rec fields -> (fields => r) -> r
Rec ? e = e

record :: Rec (?a :: Int, ?b :: String)
record = Rec where ?a=42
                   ?b="hey"

access :: Int
access = record ? ?a

Extended idea a little bit: https://gitlab.com/snippets/1874588