2 files changed, 35 insertions, 0 deletions
diff --git a/testsuite/tests/backpack/should_run/T20133.bkp b/testsuite/tests/backpack/should_run/T20133.bkp
new file mode 100644
index 0000000000..304f857ae9
--- /dev/null
+++ b/testsuite/tests/backpack/should_run/T20133.bkp
@@ -0,0 +1,34 @@
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE DataKinds #-}
+
+unit number-unknown where
+  signature NumberUnknown where
+    import GHC.Types
+    data Rep a :: RuntimeRep
+    instance Concrete (Rep a)
+    data Number a :: TYPE (Rep a)
+    plus :: Number a -> Number a -> Number a
+    multiply :: Number a -> Number a -> Number a
+  module NumberStuff where
+    import NumberUnknown
+    funcA :: Number a -> Number a -> Number a
+    funcA x y = plus x (multiply x y)
+
+unit number-unboxed-int where
+  module NumberUnknown where
+    import GHC.Types
+    import GHC.Prim
+    type Rep a = IntRep
+    type Number a = Int#
+    plus :: Int# -> Int# -> Int#
+    plus = (+#)
+    multiply :: Int# -> Int# -> Int#
+    multiply = (*#)
+
+unit main1 where
+  dependency number-unknown[NumberUnknown=number-unboxed-int:NumberUnknown]
+  module Main where
+    import NumberStuff
+    import GHC.Types
+    main = print (I# (funcA 2# 3#))
diff --git a/testsuite/tests/backpack/should_run/all.T b/testsuite/tests/backpack/should_run/all.T
index c0cde0fdc1..d4deb4f4a8 100644
--- a/testsuite/tests/backpack/should_run/all.T
+++ b/testsuite/tests/backpack/should_run/all.T
@@ -10,3 +10,4 @@ test('bkprun09', normal, backpack_run, ['-O'])
 test('T13955', normal, backpack_run, [''])
 test('T15138', normal, backpack_run, [''])
 test('T15379', normal, backpack_run,[''])
+test('T20133', expect_broken(20133), backpack_run, [''])