main.hs

newtype FooBar (names :: [(Symbol, id)]) a =
  FooBar { unFooBar :: a }

instance
  ( Show a
  ) => HasId (FooBar '[] a)
  where
  type UniqId (FooBar '[] a) = ()
  mkId (FooBar _) = ()

instance
  ( Show a
  , HasField' name a id
  , Show id
  , KnownSymbol name
  ) => HasId (FooBar '[ '(name, id)] a)
  where
  type UniqId (FooBar '[ '(name, id)] a) = id
  mkId (FooBar a) = getField @name a

instance
  ( Show a
  , HasField' name1 a id1
  , Show id1
  , KnownSymbol name1
  , HasField' name2 a id2
  , Show id2
  , KnownSymbol name2
  ) => HasId (FooBar '[ '(name1, id1), '(name2, id2)] a)
  where
  type UniqId (FooBar '[ '(name1, id1), '(name2, id2)] a) = (id1, id2)
  mkId (FooBar a) = (getField @name1 a, getField @name2 a)

instance
  ( Show a
  , HasField' name1 a id1
  , Show id1
  , KnownSymbol name1
  , HasField' name2 a id2
  , Show id2
  , KnownSymbol name2
  , HasField' name3 a id3
  , Show id3
  , KnownSymbol name3
  ) => HasId (FooBar '[ '(name1, id1), '(name2, id2), '(name3, id3)] a)
  where
  type UniqId (FooBar '[ '(name1, id1), '(name2, id2), '(name3, id3)] a) = (id1, id2, id3)
  mkId (FooBar a) = (getField @name1 a, getField @name2 a, getField @name3 a)