diff --git a/src/Polysemy/Internal/Union.hs b/src/Polysemy/Internal/Union.hs
index 209c6ec8..f0696838 100644
--- a/src/Polysemy/Internal/Union.hs
+++ b/src/Polysemy/Internal/Union.hs
@@ -295,7 +295,11 @@ extract (Union (There _) _) = error "Unsafe use of UnsafeMkElemOf"
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 -- | An empty union contains nothing, so this function is uncallable.
 absurdU :: Union '[] m a -> b
-absurdU (Union _ _) = error "Unsafe use of UnsafeMkElemOf"
+#if __GLASGOW_HASKELL__ >= 902
+absurdU = \case
+#else
+absurdU _ = error "Unsafe use of UnsafeMkElemOf"
+#endif
 
 
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