panic when checking roles off ill-kinded data type.

Issue found while working on !9628 (merged)

If I modify an existing test T15743d to have an explicit type role annotations

{-# LANGUAGE PolyKinds, DataKinds, ExplicitForAll #-}
{-# LANGUAGE RoleAnnotations #-}

module T15743 where

import Data.Kind
import Data.Proxy

data SimilarKind :: forall (c :: k) (d :: k). Proxy c -> Proxy d -> Type

data T2 k (c :: k) (a :: Proxy c) (b :: Proxy d) (x :: SimilarKind a b)
type role T2 nominal nominal nominal nominal

GHC will panic.

The ./hadrian/build ... test --only=T15743d fails with

Actual stderr output differs from expected:
--- "/tmp/ghctest-u716vd18/test   spaces/testsuite/tests/dependent/should_fail/T15743d.run/T15743d.stderr.normalised"	2023-04-11 20:06:13.352475259 +0300
+++ "/tmp/ghctest-u716vd18/test   spaces/testsuite/tests/dependent/should_fail/T15743d.run/T15743d.comp.stderr.normalised"	2023-04-11 20:06:13.352475259 +0300
@@ -1,15 +1,15 @@
+ghc: panic! (the 'impossible' happened)
+  GHC version 9.7.20230411:
+	updateRole
+  T2
+  k_aiU[sk:1]
+  []
+  Call stack:
+      CallStack (from HasCallStack):
+        callStackDoc, called at compiler/GHC/Utils/Panic.hs:<line>:<column> in <package-id>:GHC.Utils.Panic
+        pprPanic, called at compiler/GHC/Tc/TyCl/Utils.hs:<line>:<column> in <package-id>:GHC.Tc.TyCl.Utils
+  CallStack (from HasCallStack):
+    panic, called at compiler/GHC/Utils/Error.hs:<line>:<column> in <package-id>:GHC.Utils.Error
 
-T15743d.hs:10:1:
-     The kind of ‘T2’ is ill-scoped
-        Inferred kind: T2 :: forall (d :: k).
-                             forall k (c :: k) (a :: Proxy c) (b :: Proxy d) ->
-                             SimilarKind a b -> *
-      NB: Specified variables (namely: (d :: k)) always come first
-      Perhaps try this order instead:
-        k
-        (d :: k)
-        (c :: k)
-        (a :: Proxy c)
-        (b :: Proxy d)
-        (x :: SimilarKind a b)
-     In the data type declaration for ‘T2’
+
+Please report this as a GHC bug:  https://www.haskell.org/ghc/reportabug
*** unexpected failure for T15743d(normal)

Performance Metrics (test environment: local):


None collected.


Unexpected results from:
TEST="T15743d"