T17820d.hs:6:38: error:
    • Stage error: ‘foo’ is bound at stage 2 but used at stage 1
    • In the untyped splice: $(const [| 0 |] foo)
      In the Template Haskell quotation
        [d| data D = MkD {foo :: Int}
            blargh = $(const [| 0 |] foo) |]