The exact Name is not in scope

[kozross]

I have the following code:

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ScopedTypeVariables #-}

module Lib where

import           Data.Vector.Unboxed.Deriving
import           Data.Coerce
import qualified Data.Vector.Unboxed           as VU

derivingUnbox "Coerce" [t| forall a b. (Coercible a b, VU.Unbox a) => a -> b |] [| coerce |] [| coerce |]

This gives me the following errors:

src/Lib.hs|12 col 1 error| The exact Name ‘b_a5we’ is not in scope 
Probable cause: you used a unique Template Haskell name (NameU),  perhaps via newName, but did not bind it 
If that's it, then -ddump-splices might be useful 
|12 | derivingUnbox "Coerce" [t| forall a b. (Coercible a b, VU.Unbox a) => a -> b |] [| coerce |] [| coerce |] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
src/Lib.hs|12 col 1 error| The exact Name ‘b_a5we’ is not in scope 
Probable cause: you used a unique Template Haskell name (NameU),  perhaps via newName, but did not bind it 
If that's it, then -ddump-splices might be useful |12 | derivingUnbox "Coerce" [t| forall a b. (Coercible a b, VU.Unbox a) => a -> b |] [| coerce |] [| coerce |] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Did I do something wrong?