[commit: ghc] wip/ttypeable: TcTypeable: Don't generate bindings for special primitive tycons (5812687)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/ttypeable
Link       : http://ghc.haskell.org/trac/ghc/changeset/5812687c24fe95ed524ab53f750e9af9189c6ad6/ghc

>---------------------------------------------------------------

commit 5812687c24fe95ed524ab53f750e9af9189c6ad6
Author: Ben Gamari <ben at smart-cactus.org>
Date:   Wed Mar 16 15:34:03 2016 +0100

    TcTypeable: Don't generate bindings for special primitive tycons


>---------------------------------------------------------------

5812687c24fe95ed524ab53f750e9af9189c6ad6
 compiler/typecheck/TcTypeable.hs | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/compiler/typecheck/TcTypeable.hs b/compiler/typecheck/TcTypeable.hs
index 3b380f7..b59489d 100644
--- a/compiler/typecheck/TcTypeable.hs
+++ b/compiler/typecheck/TcTypeable.hs
@@ -13,7 +13,8 @@ import IfaceEnv( newGlobalBinder )
 import TcEnv
 import TcRnMonad
 import PrelNames
-import TysPrim ( primTyCons )
+import TysPrim ( primTyCons, tYPETyConName, funTyConName )
+import TysWiredIn ( runtimeRepTyCon )
 import Id
 import Type
 import TyCon
@@ -21,6 +22,7 @@ import DataCon
 import Name( getOccName )
 import OccName
 import Module
+import NameSet
 import HsSyn
 import DynFlags
 import Bag
@@ -164,6 +166,17 @@ mkTypeableTyConBinds tycons
        ; gbl_env <- tcExtendGlobalValEnv tycon_rep_ids getGblEnv
        ; return (gbl_env `addTypecheckedBinds` tc_binds) }
 
+-- | The names of the 'TyCon's which we handle explicitly in "Data.Typeable.Internal"
+-- and should not generate bindings for in "GHC.Types".
+--
+-- See Note [Mutually recursive representations of primitive types]
+specialPrimTyCons :: NameSet
+specialPrimTyCons = mkNameSet
+    [ tYPETyConName
+    , tyConName runtimeRepTyCon
+    , funTyConName
+    ]
+
 -- | Generate bindings for the type representation of a wired-in TyCon defined
 -- by the virtual "GHC.Prim" module. This is where we inject the representation
 -- bindings for primitive types into "GHC.Types"
@@ -207,7 +220,9 @@ ghcPrimTypeableBinds stuff
   where
     all_prim_tys :: [TyCon]
     all_prim_tys = [ tc' | tc <- funTyCon : primTyCons
-                         , tc' <- tc : tyConATs tc ]
+                         , tc' <- tc : tyConATs tc
+                         , not $ tyConName tc' `elemNameSet` specialPrimTyCons
+                         ]
 
     mkBind :: TyCon -> LHsBinds Id
     mkBind = mk_typeable_binds stuff