1 files changed, 19 insertions, 0 deletions
diff --git a/testsuite/tests/ado/T20540.hs b/testsuite/tests/ado/T20540.hs
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+++ b/testsuite/tests/ado/T20540.hs
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+{-# LANGUAGE ApplicativeDo, DerivingStrategies, GeneralizedNewtypeDeriving #-}
+
+module T20540 where
+
+import Data.Functor.Identity
+
+newtype F a = F (Identity a)
+  deriving newtype (Functor, Applicative, Show)
+
+x :: F Int
+x = do
+  return 3
+
+y :: F Int
+y = do
+  let a = 3
+  let b = 4
+  let c = 5
+  return $ a + b + c