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diff --git a/utils/check-exact/Orphans.hs b/utils/check-exact/Orphans.hs
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+++ b/utils/check-exact/Orphans.hs
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+{-# OPTIONS_GHC -fno-warn-orphans #-}
+{-# LANGUAGE FlexibleInstances #-}
+
+module Orphans where
+
+-- import Data.Default
+import GHC hiding (EpaComment)
+
+-- ---------------------------------------------------------------------
+
+class Default a where
+  def :: a
+
+-- ---------------------------------------------------------------------
+-- Orphan Default instances. See https://gitlab.haskell.org/ghc/ghc/-/issues/20372
+
+instance Default [a] where
+  def = []
+
+instance Default NameAnn where
+  def = mempty
+
+instance Default AnnList where
+  def = mempty
+
+instance Default AnnListItem where
+  def = mempty
+
+instance Default AnnPragma where
+  def = AnnPragma def def def
+
+instance Semigroup EpAnnImportDecl where
+  (<>) = error "unimplemented"
+instance Default EpAnnImportDecl where
+  def = EpAnnImportDecl def  Nothing  Nothing  Nothing  Nothing  Nothing
+
+instance Default HsRuleAnn where
+  def = HsRuleAnn Nothing Nothing def
+
+instance Default AnnSig where
+  def = AnnSig def  def
+
+instance Default GrhsAnn where
+  def = GrhsAnn Nothing  def
+
+instance Default EpAnnUnboundVar where
+  def = EpAnnUnboundVar def  def
+
+instance (Default a, Default b) => Default (a, b) where
+  def = (def, def)
+
+instance Default NoEpAnns where
+  def = NoEpAnns
+
+instance Default AnnParen where
+  def = AnnParen AnnParens def  def
+
+instance Default AnnExplicitSum where
+  def = AnnExplicitSum def  def  def  def
+
+instance Default EpAnnHsCase where
+  def = EpAnnHsCase def def def
+
+instance Default AnnsIf where
+  def = AnnsIf def def def def def
+
+instance Default (Maybe a) where
+  def = Nothing
+
+instance Default AnnProjection where
+  def = AnnProjection def def
+
+instance Default AnnFieldLabel where
+  def = AnnFieldLabel Nothing
+
+instance Default EpaLocation where
+  def = EpaDelta (SameLine 0) []
+
+instance Default AddEpAnn where
+  def = AddEpAnn def def
+
+instance Default AnnKeywordId where
+  def = Annlarrowtail  {- gotta pick one -}
+
+instance Default AnnContext where
+  def = AnnContext Nothing [] []
+
+instance Default EpAnnSumPat where
+  def = EpAnnSumPat def  def  def
+
+instance Default AnnsModule where
+  def = AnnsModule [] mempty