3 files changed, 29 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_fail/T12102b.hs b/testsuite/tests/typecheck/should_fail/T12102b.hs
new file mode 100644
index 0000000000..8478059c8f
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T12102b.hs
@@ -0,0 +1,21 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE TypeFamilies #-}
+module T12102b where
+
+import Data.Kind
+import GHC.TypeLits
+
+type family IsTypeLit a where
+  IsTypeLit Nat    = 'True
+  IsTypeLit Symbol = 'True
+  IsTypeLit a      = 'False
+
+data T :: forall a. (IsTypeLit a ~ 'True) => a -> Type where
+  MkNat    :: T 42
+  MkSymbol :: T "Don't panic!"
+
+deriving instance Show (T a)
diff --git a/testsuite/tests/typecheck/should_fail/T12102b.stderr b/testsuite/tests/typecheck/should_fail/T12102b.stderr
new file mode 100644
index 0000000000..d93b7fda9c
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T12102b.stderr
@@ -0,0 +1,7 @@
+
+T12102b.hs:21:25: error:
+    • Couldn't match expected kind ‘'True’
+                  with actual kind ‘IsTypeLit a0’
+      The type variable ‘a0’ is ambiguous
+    • In the first argument of ‘Show’, namely ‘(T a)’
+      In the stand-alone deriving instance for ‘Show (T a)’
diff --git a/testsuite/tests/typecheck/should_fail/all.T b/testsuite/tests/typecheck/should_fail/all.T
index d155ca0e8c..fec3a3ae67 100644
--- a/testsuite/tests/typecheck/should_fail/all.T
+++ b/testsuite/tests/typecheck/should_fail/all.T
@@ -411,6 +411,7 @@ test('T12083a', normal, compile_fail, [''])
 test('T12083b', normal, compile_fail, [''])
 test('T11974b', normal, compile_fail, [''])
 test('T12102', normal, compile, [''])
+test('T12102b', normal, compile_fail, [''])
 test('T12151', normal, compile_fail, [''])
 test('T7437', normal, compile_fail, [''])
 test('T12177', normal, compile_fail, [''])