Core, Unit and Z0T

Are Unit and Z0T considered equal?


In GHC/Base.hcr they are both defined:

-----
  %data GHCziBase.Unit =
    {GHCziBase.Unit};
  %data GHCziBase.Z0T =
    {GHCziBase.Z0T};
-----


In .../ghc/compiler/prelude/primops.txt at line 2669 we find:

-----
primop  FinalizeWeakOp "finalizeWeak#" GenPrimOp
   Weak# a -> State# RealWorld -> (# State# RealWorld, Int#,
              (State# RealWorld -> (# State# RealWorld, Unit #)) #)
   with
   usage            = { mangle FinalizeWeakOp [mkM, mkP]
                               (mkR . (inUB FinalizeWeakOp
                                            [id,id,inFun FinalizeWeakOp 
mkR mkM])) }
   has_side_effects = True
   out_of_line      = True
-----

Here Unit is used but in .../GHC/Weak.hcr at line 57 when using 
GHCziPrim.finalizzeWeakzh it is tried to unify with Z0T:

-----
  GHCziWeak.finalizze :: %forall v . GHCziWeak.Weak v ->
                                     GHCziIOBase.IO GHCziBase.Z0T =
    \ @ v
      (ds::GHCziWeak.Weak v)
      (eta::GHCziPrim.Statezh GHCziPrim.RealWorld) ->
        %case ds %of (wild::GHCziWeak.Weak v)
          {GHCziWeak.Weak (w::GHCziPrim.Weakzh v) ->
             %case (GHCziPrim.finalizzeWeakzh @ v w eta)
             %of (wild1::GHCziPrim.Z3H
                         (GHCziPrim.Statezh GHCziPrim.RealWorld)
                         GHCziPrim.Intzh
                         (GHCziPrim.Statezh GHCziPrim.RealWorld ->
                          GHCziPrim.Z2H
                          (GHCziPrim.Statezh GHCziPrim.RealWorld)
                          GHCziBase.Z0T))
-----


I have looked around a bit and tried to see if there is any 
documentation that says that Unit and Z0T are the same but I didn't find 
any.



Sincerely,
 Tobias