1 files changed, 20 insertions, 0 deletions
diff --git a/testsuite/tests/simplCore/should_compile/T17722A.hs b/testsuite/tests/simplCore/should_compile/T17722A.hs
new file mode 100644
index 0000000000..1f63582beb
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T17722A.hs
@@ -0,0 +1,20 @@
+module T17722A (Validation(..)) where
+
+data Validation e a
+  = Failure e
+  | Success a
+
+instance Functor (Validation e) where
+   fmap _ (Failure e) = Failure e
+   fmap f (Success a) = Success (f a)
+
+(<.>) :: Semigroup e => Validation e (t -> a) -> Validation e t -> Validation e a
+Failure e1 <.> b = Failure $ case b of
+  Failure e2 -> e1 <> e2
+  Success _  -> e1
+Success _  <.> Failure e  = Failure  e
+Success f  <.> Success x  = Success (f x)
+
+instance Semigroup e => Applicative (Validation e) where
+  pure = Success
+  (<*>) = (<.>)