Core Lint error with unsafeCoerce and phantom parameter

The following program fails -dcore-lint -O in master, as of 994bda56:

module M where

import Unsafe.Coerce
import Data.Kind

type Phantom :: Type -> Type
data Phantom a = MkPhantom

newtype Id a = MkId a
newtype First a = MkFirst (Id a)
data Second a = MkSecond (First a)
data Third a = MkThird !(Second a)

a :: Second (Phantom Int)
a = MkSecond (MkFirst (MkId MkPhantom))

uc :: Second (Phantom Int) -> Second (Phantom Bool)
uc = unsafeCoerce

b :: Third (Phantom Bool)
b = MkThird (uc a)

$ ./stage1/bin/ghc -dlint -O -dno-typeable-binds M
[1 of 1] Compiling M                ( M.hs, M.o ) [Source file changed]
*** Core Lint errors : in result of Simplifier ***
M.hs:21:1: warning:
    Role incompatibility: expected nominal, got representational
    in SelCo:Tc(0) (Sym co_azY)
    In the RHS of b :: Third (Phantom Bool)
    In a case alternative: (UnsafeRefl co_azY :: Second (Phantom Bool)
                                                 ~# Second (Phantom Int))
    Substitution: <InScope = {co_azY}
                   IdSubst   = []
                   TvSubst   = []
                   CvSubst   = [azY :-> co_azY]>

If Lint is not enabled, GHC shows an assertion failure

<no location info>: error:
    panic! (the 'impossible' happened)
  GHC version 9.7.20230506:
	ASSERT failed!
  Coercion = Sym Univ(nominal CorePrep
                      :: Second (Phantom Bool), Second (Phantom Int))
  LHS ty = Second (Phantom Int)
  RHS ty = Second (Phantom Bool)
  cs = Tc(0)
  coercion role = nominal
  Call stack:
      CallStack (from HasCallStack):
        assertPpr, called at compiler/GHC/Core/Coercion.hs:1152:5 in ghc-9.7-inplace:GHC.Core.Coercion
        mkSelCo_maybe, called at compiler/GHC/Core/Coercion.hs:1144:16 in ghc-9.7-inplace:GHC.Core.Coercion
        mkSelCo, called at compiler/GHC/Core/Type.hs:975:44 in ghc-9.7-inplace:GHC.Core.Type
  CallStack (from HasCallStack):
    panic, called at compiler/GHC/Utils/Error.hs:479:29 in ghc-9.7-inplace:GHC.Utils.Error

GHC 9.4 is fine, I haven't checked 9.6.

The use of unsafeCoerce should be fine: the program compiles correctly if it is replaced by coerce. The bug was originally found in the context of linear-base https://github.com/tweag/linear-base/issues/452, which is more complex and cannot use the coerce workaround.