Test Trac #12081

3 files changed, 17 insertions, 0 deletions

diff --git a/testsuite/tests/dependent/should_fail/T12081.hs b/testsuite/tests/dependent/should_fail/T12081.hs
new file mode 100644
index 0000000000..f68de420cb
--- /dev/null
+++ b/testsuite/tests/dependent/should_fail/T12081.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE TypeInType #-}
+
+module T12081 where
+
+data Nat = Z | S Nat
+
+class C (n :: Nat) where
+  type T n :: Nat
+  f :: (a :: T n)
diff --git a/testsuite/tests/dependent/should_fail/T12081.stderr b/testsuite/tests/dependent/should_fail/T12081.stderr
new file mode 100644
index 0000000000..77d5a40353
--- /dev/null
+++ b/testsuite/tests/dependent/should_fail/T12081.stderr
@@ -0,0 +1,7 @@
+
+T12081.hs:9:14: error:
+    • Type constructor ‘T’ cannot be used here
+        (it is defined and used in the same recursive group)
+    • In the kind ‘T n’
+      In the type signature: f :: (a :: T n)
+      In the class declaration for ‘C’
diff --git a/testsuite/tests/dependent/should_fail/all.T b/testsuite/tests/dependent/should_fail/all.T
index f1ed340aeb..b9c82f131b 100644
--- a/testsuite/tests/dependent/should_fail/all.T
+++ b/testsuite/tests/dependent/should_fail/all.T
@@ -15,3 +15,4 @@ test('KindLevelsB', normal, compile_fail, [''])
 test('T11473', normal, compile_fail, [''])
 test('T11471', normal, compile_fail, [''])
 test('T12174', normal, compile_fail, [''])
+test('T12081', normal, compile_fail, [''])