Add pattern TypeRep (#19691), exported by Type.Reflection.

2 files changed, 34 insertions, 0 deletions

diff --git a/testsuite/tests/lib/base/T19691.hs b/testsuite/tests/lib/base/T19691.hs
new file mode 100644
index 0000000000..0525b8b499
--- /dev/null
+++ b/testsuite/tests/lib/base/T19691.hs
@@ -0,0 +1,33 @@
+{-# Language DerivingStrategies       #-}
+{-# Language TypeApplications         #-}
+{-# Language GADTs                    #-}
+{-# Language StandaloneKindSignatures #-}
+{-# Language TypeFamilies             #-}
+
+import Data.Kind
+import Type.Reflection
+
+type Dict :: Constraint -> Type
+data Dict cls where
+ Dict :: cls => Dict cls
+
+deriving stock
+  instance Show (Dict cls)
+
+type WitnessList :: forall k. k -> Type
+data WitnessList as where
+  WitnessList :: Typeable a => WitnessList (f a)
+
+deriving stock
+  instance Show (WitnessList as)
+
+toDict :: TypeRep a -> Dict (Typeable a)
+toDict TypeRep = Dict
+
+witness :: TypeRep as -> Maybe (WitnessList as)
+witness (App _ TypeRep) = Just WitnessList
+
+main :: IO ()
+main = do
+  print (toDict  (TypeRep @[Int]))
+  print (witness (TypeRep @[Int]))
diff --git a/testsuite/tests/lib/base/all.T b/testsuite/tests/lib/base/all.T
index 6bf890c148..170bfe4d85 100644
--- a/testsuite/tests/lib/base/all.T
+++ b/testsuite/tests/lib/base/all.T
@@ -3,3 +3,4 @@ test('T16586', normal, compile_and_run, ['-O2'])
 # Event-manager not supported on Windows
 test('T16916', when(opsys('mingw32'), skip), compile_and_run, ['-O2 -threaded -with-rtsopts="-I0" -rtsopts'])
 test('T17310', normal, compile, [''])
+test('T19691', normal, compile, [''])
\ No newline at end of file