Serialise nested unfoldings across module boundaries

As Roman reported in #4428, nested let-bindings weren't
being recorded with their unfoldings.  Needless to say,
fixing this had more knock-on effects than I expected.

5 files changed, 108 insertions, 95 deletions

diff --git a/compiler/iface/BinIface.hs b/compiler/iface/BinIface.hs
index f7a9aa297a..7c84778d0c 100644
--- a/compiler/iface/BinIface.hs
+++ b/compiler/iface/BinIface.hs
@@ -1209,15 +1209,19 @@ instance Binary IfaceUnfolding where
 	put_ bh b
 	put_ bh c
 	put_ bh d
-    put_ bh (IfWrapper a n) = do
+    put_ bh (IfLclWrapper a n) = do
 	putByte bh 2
 	put_ bh a
 	put_ bh n
-    put_ bh (IfDFunUnfold as) = do
+    put_ bh (IfExtWrapper a n) = do
 	putByte bh 3
+	put_ bh a
+	put_ bh n
+    put_ bh (IfDFunUnfold as) = do
+	putByte bh 4
 	put_ bh as
     put_ bh (IfCompulsory e) = do
-	putByte bh 4
+	putByte bh 5
 	put_ bh e
     get bh = do
 	h <- getByte bh
@@ -1232,8 +1236,11 @@ instance Binary IfaceUnfolding where
 		  return (IfInlineRule a b c d)
 	  2 -> do a <- get bh
 		  n <- get bh
-		  return (IfWrapper a n)
-	  3 -> do as <- get bh
+		  return (IfLclWrapper a n)
+	  3 -> do a <- get bh
+		  n <- get bh
+		  return (IfExtWrapper a n)
+	  4 -> do as <- get bh
 		  return (IfDFunUnfold as)
 	  _ -> do e <- get bh
 		  return (IfCompulsory e)
diff --git a/compiler/iface/IfaceSyn.lhs b/compiler/iface/IfaceSyn.lhs
index 3d40b3858e..f86f4b9558 100644
--- a/compiler/iface/IfaceSyn.lhs
+++ b/compiler/iface/IfaceSyn.lhs
@@ -137,9 +137,9 @@ data IfaceConDecl
 						-- or 1-1 corresp with arg tys
 
 data IfaceInst 
-  = IfaceInst { ifInstCls  :: Name,     		-- See comments with
+  = IfaceInst { ifInstCls  :: IfExtName,     		-- See comments with
 		ifInstTys  :: [Maybe IfaceTyCon],	-- the defn of Instance
-		ifDFun     :: Name,     		-- The dfun
+		ifDFun     :: IfExtName,     		-- The dfun
 		ifOFlag    :: OverlapFlag,		-- Overlap flag
 		ifInstOrph :: Maybe OccName }		-- See Note [Orphans]
 	-- There's always a separate IfaceDecl for the DFun, which gives 
@@ -150,7 +150,7 @@ data IfaceInst
 	-- and if the head does not change it won't be used if it wasn't before
 
 data IfaceFamInst
-  = IfaceFamInst { ifFamInstFam   :: Name                -- Family tycon
+  = IfaceFamInst { ifFamInstFam   :: IfExtName                -- Family tycon
 		 , ifFamInstTys   :: [Maybe IfaceTyCon]  -- Rough match types
 		 , ifFamInstTyCon :: IfaceTyCon		 -- Instance decl
 		 }
@@ -160,7 +160,7 @@ data IfaceRule
 	ifRuleName   :: RuleName,
 	ifActivation :: Activation,
 	ifRuleBndrs  :: [IfaceBndr],	-- Tyvars and term vars
-	ifRuleHead   :: Name,   	-- Head of lhs
+	ifRuleHead   :: IfExtName,   	-- Head of lhs
 	ifRuleArgs   :: [IfaceExpr],	-- Args of LHS
 	ifRuleRhs    :: IfaceExpr,
 	ifRuleAuto   :: Bool,
@@ -222,20 +222,21 @@ data IfaceUnfolding
 		 Bool		-- OK to inline even if context is boring
                  IfaceExpr 
 
-  | IfWrapper    Arity Name	  -- NB: we need a Name (not just OccName) because the worker
-				  --     can simplify to a function in another module.
+  | IfExtWrapper Arity IfExtName  -- NB: sometimes we need a IfExtName (not just IfLclName) 
+  | IfLclWrapper Arity IfLclName  --     because the worker can simplify to a function in 
+    		       		  --     another module.
 
   | IfDFunUnfold [IfaceExpr]
 
 --------------------------------
 data IfaceExpr
-  = IfaceLcl 	FastString
-  | IfaceExt    Name
+  = IfaceLcl 	IfLclName
+  | IfaceExt    IfExtName
   | IfaceType   IfaceType
   | IfaceTuple 	Boxity [IfaceExpr]		-- Saturated; type arguments omitted
   | IfaceLam 	IfaceBndr IfaceExpr
   | IfaceApp 	IfaceExpr IfaceExpr
-  | IfaceCase	IfaceExpr FastString IfaceType [IfaceAlt]
+  | IfaceCase	IfaceExpr IfLclName IfaceType [IfaceAlt]
   | IfaceLet	IfaceBinding  IfaceExpr
   | IfaceNote	IfaceNote IfaceExpr
   | IfaceCast   IfaceExpr IfaceCoercion
@@ -246,13 +247,13 @@ data IfaceExpr
 data IfaceNote = IfaceSCC CostCentre
                | IfaceCoreNote String
 
-type IfaceAlt = (IfaceConAlt, [FastString], IfaceExpr)
-	-- Note: FastString, not IfaceBndr (and same with the case binder)
+type IfaceAlt = (IfaceConAlt, [IfLclName], IfaceExpr)
+	-- Note: IfLclName, not IfaceBndr (and same with the case binder)
 	-- We reconstruct the kind/type of the thing from the context
 	-- thus saving bulk in interface files
 
 data IfaceConAlt = IfaceDefault
- 		 | IfaceDataAlt Name
+ 		 | IfaceDataAlt IfExtName
 		 | IfaceTupleAlt Boxity
 		 | IfaceLitAlt Literal
 
@@ -263,7 +264,7 @@ data IfaceBinding
 -- IfaceLetBndr is like IfaceIdBndr, but has IdInfo too
 -- It's used for *non-top-level* let/rec binders
 -- See Note [IdInfo on nested let-bindings]
-data IfaceLetBndr = IfLetBndr FastString IfaceType IfaceIdInfo
+data IfaceLetBndr = IfLetBndr IfLclName IfaceType IfaceIdInfo
 \end{code}
 
 Note [Expose recursive functions]
@@ -280,10 +281,8 @@ that came up was a NOINLINE pragma on a let-binding inside an INLINE
 function.  The user (Duncan Coutts) really wanted the NOINLINE control
 to cross the separate compilation boundary.
 
-So a IfaceLetBndr keeps a trimmed-down list of IfaceIdInfo stuff.
-Currently we only actually retain InlinePragInfo, but in principle we could
-add strictness etc.
-
+In general we retain all info that is left by CoreTidy.tidyLetBndr, since
+that is what is seen by importing module with --make
 
 Note [Orphans]: the ifInstOrph and ifRuleOrph fields
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -640,11 +639,11 @@ pprIfaceExpr add_par (IfaceLet (IfaceRec pairs) body)
 
 pprIfaceExpr add_par (IfaceNote note body) = add_par (ppr note <+> pprParendIfaceExpr body)
 
-ppr_alt :: (IfaceConAlt, [FastString], IfaceExpr) -> SDoc
+ppr_alt :: (IfaceConAlt, [IfLclName], IfaceExpr) -> SDoc
 ppr_alt (con, bs, rhs) = sep [ppr_con_bs con bs, 
 			      arrow <+> pprIfaceExpr noParens rhs]
 
-ppr_con_bs :: IfaceConAlt -> [FastString] -> SDoc
+ppr_con_bs :: IfaceConAlt -> [IfLclName] -> SDoc
 ppr_con_bs (IfaceTupleAlt tup_con) bs = tupleParens tup_con (interpp'SP bs)
 ppr_con_bs con bs		      = ppr con <+> hsep (map ppr bs)
   
@@ -695,7 +694,9 @@ instance Outputable IfaceUnfolding where
   ppr (IfCoreUnfold s e)   = (if s then ptext (sLit "<stable>") else empty) <+> parens (ppr e)
   ppr (IfInlineRule a uok bok e) = sep [ptext (sLit "InlineRule") <+> ppr (a,uok,bok),
       		           	        pprParendIfaceExpr e]
-  ppr (IfWrapper a wkr)    = ptext (sLit "Worker:") <+> ppr wkr
+  ppr (IfLclWrapper a wkr) = ptext (sLit "Worker(lcl):") <+> ppr wkr
+                             <+> parens (ptext (sLit "arity") <+> int a)
+  ppr (IfExtWrapper a wkr) = ptext (sLit "Worker(ext0:") <+> ppr wkr
                              <+> parens (ptext (sLit "arity") <+> int a)
   ppr (IfDFunUnfold ns)    = ptext (sLit "DFun:")
                              <+> brackets (pprWithCommas pprParendIfaceExpr ns)
@@ -819,7 +820,8 @@ freeNamesIfUnfold :: IfaceUnfolding -> NameSet
 freeNamesIfUnfold (IfCoreUnfold _ e)     = freeNamesIfExpr e
 freeNamesIfUnfold (IfCompulsory e)       = freeNamesIfExpr e
 freeNamesIfUnfold (IfInlineRule _ _ _ e) = freeNamesIfExpr e
-freeNamesIfUnfold (IfWrapper _ v)        = unitNameSet v
+freeNamesIfUnfold (IfExtWrapper _ v)     = unitNameSet v
+freeNamesIfUnfold (IfLclWrapper {})      = emptyNameSet
 freeNamesIfUnfold (IfDFunUnfold vs)      = fnList freeNamesIfExpr vs
 
 freeNamesIfExpr :: IfaceExpr -> NameSet
diff --git a/compiler/iface/IfaceType.lhs b/compiler/iface/IfaceType.lhs
index 47772d7c46..c97e16eef2 100644
--- a/compiler/iface/IfaceType.lhs
+++ b/compiler/iface/IfaceType.lhs
@@ -7,7 +7,9 @@ This module defines interface types and binders
 
 \begin{code}
 module IfaceType (
-	IfaceType(..), IfaceKind, IfacePredType(..), IfaceTyCon(..),
+	IfExtName, IfLclName,
+
+        IfaceType(..), IfaceKind, IfacePredType(..), IfaceTyCon(..),
 	IfaceContext, IfaceBndr(..), IfaceTvBndr, IfaceIdBndr, IfaceCoercion,
 	ifaceTyConName,
 
@@ -41,19 +43,24 @@ import FastString
 %************************************************************************
 
 \begin{code}
+type IfLclName = FastString	-- A local name in iface syntax
+
+type IfExtName = Name	-- An External or WiredIn Name can appear in IfaceSyn
+     	       	 	-- (However Internal or System Names never should)
+
 data IfaceBndr 		-- Local (non-top-level) binders
   = IfaceIdBndr {-# UNPACK #-} !IfaceIdBndr
   | IfaceTvBndr {-# UNPACK #-} !IfaceTvBndr
 
-type IfaceIdBndr  = (FastString, IfaceType)
-type IfaceTvBndr  = (FastString, IfaceKind)
+type IfaceIdBndr  = (IfLclName, IfaceType)
+type IfaceTvBndr  = (IfLclName, IfaceKind)
 
 -------------------------------
 type IfaceKind     = IfaceType
 type IfaceCoercion = IfaceType
 
 data IfaceType
-  = IfaceTyVar    FastString			-- Type variable only, not tycon
+  = IfaceTyVar    IfLclName			-- Type variable only, not tycon
   | IfaceAppTy    IfaceType IfaceType
   | IfaceForAllTy IfaceTvBndr IfaceType
   | IfacePredTy   IfacePredType
@@ -62,14 +69,14 @@ data IfaceType
   | IfaceFunTy  IfaceType IfaceType
 
 data IfacePredType 	-- NewTypes are handled as ordinary TyConApps
-  = IfaceClassP Name [IfaceType]
+  = IfaceClassP IfExtName [IfaceType]
   | IfaceIParam (IPName OccName) IfaceType
   | IfaceEqPred IfaceType IfaceType
 
 type IfaceContext = [IfacePredType]
 
 data IfaceTyCon 	-- Abbreviations for common tycons with known names
-  = IfaceTc Name	-- The common case
+  = IfaceTc IfExtName	-- The common case
   | IfaceIntTc | IfaceBoolTc | IfaceCharTc
   | IfaceListTc | IfacePArrTc
   | IfaceTupTc Boxity Arity 
@@ -78,7 +85,7 @@ data IfaceTyCon 	-- Abbreviations for common tycons with known names
   | IfaceLiftedTypeKindTc | IfaceOpenTypeKindTc | IfaceUnliftedTypeKindTc
   | IfaceUbxTupleKindTc | IfaceArgTypeKindTc 
 
-ifaceTyConName :: IfaceTyCon -> Name
+ifaceTyConName :: IfaceTyCon -> IfExtName
 ifaceTyConName IfaceIntTc  	       = intTyConName
 ifaceTyConName IfaceBoolTc 	       = boolTyConName
 ifaceTyConName IfaceCharTc 	       = charTyConName
@@ -173,7 +180,7 @@ instance Outputable IfaceBndr where
 pprIfaceBndrs :: [IfaceBndr] -> SDoc
 pprIfaceBndrs bs = sep (map ppr bs)
 
-pprIfaceIdBndr :: (FastString, IfaceType) -> SDoc
+pprIfaceIdBndr :: (IfLclName, IfaceType) -> SDoc
 pprIfaceIdBndr (name, ty) = hsep [ppr name, dcolon, ppr ty]
 
 pprIfaceTvBndr :: IfaceTvBndr -> SDoc
@@ -284,11 +291,11 @@ pabrackets p = ptext (sLit "[:") <> p <> ptext (sLit ":]")
 
 \begin{code}
 ----------------
-toIfaceTvBndr :: TyVar -> (FastString, IfaceType)
+toIfaceTvBndr :: TyVar -> (IfLclName, IfaceType)
 toIfaceTvBndr tyvar   = (occNameFS (getOccName tyvar), toIfaceKind (tyVarKind tyvar))
-toIfaceIdBndr :: Id -> (FastString, IfaceType)
+toIfaceIdBndr :: Id -> (IfLclName, IfaceType)
 toIfaceIdBndr id      = (occNameFS (getOccName id),    toIfaceType (idType id))
-toIfaceTvBndrs :: [TyVar] -> [(FastString, IfaceType)]
+toIfaceTvBndrs :: [TyVar] -> [(IfLclName, IfaceType)]
 toIfaceTvBndrs tyvars = map toIfaceTvBndr tyvars
 
 toIfaceBndr :: Var -> IfaceBndr
diff --git a/compiler/iface/MkIface.lhs b/compiler/iface/MkIface.lhs
index a8ea826c94..0d592160ca 100644
--- a/compiler/iface/MkIface.lhs
+++ b/compiler/iface/MkIface.lhs
@@ -439,7 +439,7 @@ addFingerprints hsc_env mb_old_fingerprint iface0 new_decls
           | isWiredInName name  =  putNameLiterally bh name 
            -- wired-in names don't have fingerprints
           | otherwise
-          = ASSERT( isExternalName name )
+          = ASSERT2( isExternalName name, ppr name )
 	    let hash | nameModule name /= this_mod =  global_hash_fn name
                      | otherwise = 
                         snd (lookupOccEnv local_env (getOccName name)
@@ -1322,11 +1322,7 @@ tyThingToIfaceDecl (AnId id)
   = IfaceId { ifName      = getOccName id,
 	      ifType      = toIfaceType (idType id),
 	      ifIdDetails = toIfaceIdDetails (idDetails id),
-	      ifIdInfo    = info }
-  where
-    info = case toIfaceIdInfo (idInfo id) of
-		[]    -> NoInfo
-		items -> HasInfo items
+	      ifIdInfo    = toIfaceIdInfo (idInfo id) }
 
 tyThingToIfaceDecl (AClass clas)
   = IfaceClass { ifCtxt	  = toIfaceContext sc_theta,
@@ -1482,18 +1478,9 @@ famInstToIfaceFamInst (FamInst { fi_tycon = tycon,
 toIfaceLetBndr :: Id -> IfaceLetBndr
 toIfaceLetBndr id  = IfLetBndr (occNameFS (getOccName id))
 			       (toIfaceType (idType id)) 
-			       prag_info
-  where
-	-- Stripped-down version of tcIfaceIdInfo
-	-- Change this if you want to export more IdInfo for
-	-- non-top-level Ids.  Don't forget to change
-	-- CoreTidy.tidyLetBndr too!
-	--
-	-- See Note [IdInfo on nested let-bindings] in IfaceSyn
-    id_info = idInfo id
-    inline_prag = inlinePragInfo id_info
-    prag_info | isDefaultInlinePragma inline_prag = NoInfo
-	      | otherwise		          = HasInfo [HsInline inline_prag]
+			       (toIfaceIdInfo (idInfo id))
+  -- Put into the interface file any IdInfo that CoreTidy.tidyLetBndr 
+  -- has left on the Id.  See Note [IdInfo on nested let-bindings] in IfaceSyn
 
 --------------------------
 toIfaceIdDetails :: IdDetails -> IfaceIdDetails
@@ -1504,11 +1491,13 @@ toIfaceIdDetails (RecSelId { sel_naughty = n
 toIfaceIdDetails other	     		        = pprTrace "toIfaceIdDetails" (ppr other) 
                                                   IfVanillaId   -- Unexpected
 
-toIfaceIdInfo :: IdInfo -> [IfaceInfoItem]
+toIfaceIdInfo :: IdInfo -> IfaceIdInfo
 toIfaceIdInfo id_info
-  = catMaybes [arity_hsinfo, caf_hsinfo, strict_hsinfo, 
-	       inline_hsinfo,  unfold_hsinfo] 
-	       -- NB: strictness must be before unfolding
+  = case catMaybes [arity_hsinfo, caf_hsinfo, strict_hsinfo, 
+	            inline_hsinfo,  unfold_hsinfo] of
+       []    -> NoInfo
+       infos -> HasInfo infos
+	       -- NB: strictness must appear in the list before unfolding
 	       -- See TcIface.tcUnfolding
   where
     ------------  Arity  --------------
@@ -1547,7 +1536,10 @@ toIfUnfolding lb (CoreUnfolding { uf_tmpl = rhs, uf_arity = arity
           -> case guidance of
                UnfWhen unsat_ok boring_ok -> IfInlineRule arity unsat_ok boring_ok if_rhs
                _other                     -> IfCoreUnfold True if_rhs
-	InlineWrapper w  -> IfWrapper arity (idName w)
+	InlineWrapper w | isExternalName n -> IfExtWrapper arity n
+	                | otherwise        -> IfLclWrapper arity (getFS n)
+			where
+                          n = idName w
         InlineCompulsory -> IfCompulsory if_rhs
         InlineRhs        -> IfCoreUnfold False if_rhs
 	-- Yes, even if guidance is UnfNever, expose the unfolding
diff --git a/compiler/iface/TcIface.lhs b/compiler/iface/TcIface.lhs
index ba1da6028c..c39b713f9f 100644
--- a/compiler/iface/TcIface.lhs
+++ b/compiler/iface/TcIface.lhs
@@ -39,8 +39,8 @@ import TyCon
 import DataCon
 import TysWiredIn
 import TysPrim		( anyTyConOfKind )
-import Var              ( TyVar )
-import BasicTypes	( nonRuleLoopBreaker )
+import Var              ( Var, TyVar )
+import BasicTypes	( Arity, nonRuleLoopBreaker )
 import qualified Var
 import VarEnv
 import Name
@@ -1038,8 +1038,23 @@ tcUnfolding name _ _ (IfInlineRule arity unsat_ok boring_ok if_expr)
                                                  (UnfWhen unsat_ok boring_ok))
     }
 
-tcUnfolding name ty info (IfWrapper arity wkr)
-  = do 	{ mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
+tcUnfolding name dfun_ty _ (IfDFunUnfold ops)
+  = do { mb_ops1 <- forkM_maybe doc $ mapM tcIfaceExpr ops
+       ; return (case mb_ops1 of
+       	 	    Nothing   -> noUnfolding
+                    Just ops1 -> mkDFunUnfolding dfun_ty ops1) }
+  where
+    doc = text "Class ops for dfun" <+> ppr name
+
+tcUnfolding name ty info (IfExtWrapper arity wkr)
+  = tcIfaceWrapper name ty info arity (tcIfaceExtId wkr)
+tcUnfolding name ty info (IfLclWrapper arity wkr)
+  = tcIfaceWrapper name ty info arity (tcIfaceLclId wkr)
+
+-------------
+tcIfaceWrapper :: Name -> Type -> IdInfo -> Arity -> IfL Id -> IfL Unfolding
+tcIfaceWrapper name ty info arity get_worker
+  = do 	{ mb_wkr_id <- forkM_maybe doc get_worker
 	; us <- newUniqueSupply
 	; return (case mb_wkr_id of
 		     Nothing     -> noUnfolding
@@ -1056,15 +1071,7 @@ tcUnfolding name ty info (IfWrapper arity wkr)
 	-- before unfolding
     strict_sig = case strictnessInfo info of
 		   Just sig -> sig
-		   Nothing  -> pprPanic "Worker info but no strictness for" (ppr wkr)
-
-tcUnfolding name dfun_ty _ (IfDFunUnfold ops)
-  = do { mb_ops1 <- forkM_maybe doc $ mapM tcIfaceExpr ops
-       ; return (case mb_ops1 of
-       	 	    Nothing   -> noUnfolding
-                    Just ops1 -> mkDFunUnfolding dfun_ty ops1) }
-  where
-    doc = text "Class ops for dfun" <+> ppr name
+		   Nothing  -> pprPanic "Worker info but no strictness for" (ppr name)
 \end{code}
 
 For unfoldings we try to do the job lazily, so that we never type check
@@ -1078,22 +1085,28 @@ tcPragExpr name expr
 
                 -- Check for type consistency in the unfolding
     ifDOptM Opt_DoCoreLinting $ do
-        in_scope <- get_in_scope_ids
+        in_scope <- get_in_scope
         case lintUnfolding noSrcLoc in_scope core_expr' of
           Nothing       -> return ()
-          Just fail_msg -> pprPanic "Iface Lint failure" (hang doc 2 fail_msg)
-
+          Just fail_msg -> do { mod <- getIfModule 
+                              ; pprPanic "Iface Lint failure" 
+                                  (vcat [ ptext (sLit "In interface for") <+> ppr mod
+                                        , hang doc 2 fail_msg ]) }
     return core_expr'
   where
     doc = text "Unfolding of" <+> ppr name
-    get_in_scope_ids 	-- Urgh; but just for linting
-	= setLclEnv () $ 
-	  do	{ env <- getGblEnv 
-		; case if_rec_types env of {
-			  Nothing -> return [] ;
-			  Just (_, get_env) -> do
-		{ type_env <- get_env
-		; return (typeEnvIds type_env) }}}
+
+    get_in_scope :: IfL [Var] -- Totally disgusting; but just for linting
+    get_in_scope 	
+	= do { (gbl_env, lcl_env) <- getEnvs
+             ; setLclEnv () $ do
+	     { case if_rec_types gbl_env of {
+		  Nothing -> return [] ;
+		  Just (_, get_env) -> do
+	     { type_env <- get_env
+             ; return (varEnvElts (if_tv_env lcl_env) ++
+                       varEnvElts (if_id_env lcl_env) ++
+                       typeEnvIds type_env) }}}}
 \end{code}
 
 
@@ -1229,17 +1242,9 @@ tcIfaceLetBndr :: IfaceLetBndr -> IfL Id
 tcIfaceLetBndr (IfLetBndr fs ty info)
   = do	{ name <- newIfaceName (mkVarOccFS fs)
 	; ty' <- tcIfaceType ty
-	; case info of
-		NoInfo    -> return (mkLocalId name ty')
-		HasInfo i -> return (mkLocalIdWithInfo name ty' (tc_info i)) } 
-  where
-	-- Similar to tcIdInfo, but much simpler
-    tc_info [] = vanillaIdInfo
-    tc_info (HsInline p     : i) = tc_info i `setInlinePragInfo` p 
-    tc_info (HsArity a      : i) = tc_info i `setArityInfo` a 
-    tc_info (HsStrictness s : i) = tc_info i `setStrictnessInfo` Just s 
-    tc_info (other          : i) = pprTrace "tcIfaceLetBndr: discarding unexpected IdInfo" 
-					    (ppr other) (tc_info i)
+        ; id_info <- tcIdInfo False {- Don't ignore prags; we are inside one! -}
+                              name ty' info
+	; return (mkLocalIdWithInfo name ty' id_info) } 
 
 -----------------------
 newExtCoreBndr :: IfaceLetBndr -> IfL Id