ATs are now implicitTyThings

Mon Sep 18 19:36:03 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
  * ATs are now implicitTyThings
  Tue Sep  5 21:09:54 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
    * ATs are now implicitTyThings

diff --git a/compiler/iface/LoadIface.lhs b/compiler/iface/LoadIface.lhs
index c91aa63..21332fa 100644 (file)
--- a/compiler/iface/LoadIface.lhs
+++ b/compiler/iface/LoadIface.lhs
@@ -301,7 +301,6 @@ loadDecl ignore_prags mod (_version, decl)
          main_name      <- mk_new_bndr mod Nothing (ifName decl)
        ; implicit_names <- mapM (mk_new_bndr mod (Just main_name)) 
                                 (ifaceDeclSubBndrs decl)
-        ; at_names       <- mapM (mk_new_bndr mod  (Just main_name)) (atNames decl)
 
        -- Typecheck the thing, lazily
        -- NB. firstly, the laziness is there in case we never need the
@@ -318,7 +317,6 @@ loadDecl ignore_prags mod (_version, decl)
                                                  ppr n $$ ppr (stripped_decl))
 
        ; returnM $ (main_name, thing) :  [(n, lookup n) | n <- implicit_names]
-                                      ++ zip at_names (atThings thing)
        }
                -- We build a list from the *known* names, with (lookup n) thunks
                -- as the TyThings.  That way we can extend the PTE without poking the
@@ -337,12 +335,6 @@ loadDecl ignore_prags mod (_version, decl)
                          (importedSrcLoc (showSDoc (ppr (moduleName mod))))
                        -- ToDo: qualify with the package name if necessary
 
-    atNames (IfaceClass {ifATs = ats}) = [ifName at | at <- ats]
-    atNames _                          = []
-
-    atThings (AClass cla) = [ATyCon at | at <- classATs cla]
-    atThings _            = []
-
     doc = ptext SLIT("Declaration for") <+> ppr (ifName decl)
 
 discardDeclPrags :: IfaceDecl -> IfaceDecl
@@ -364,12 +356,12 @@ ifaceDeclSubBndrs :: IfaceDecl -> [OccName]
 --
 -- If you change this, make sure you change HscTypes.implicitTyThings in sync
 
-ifaceDeclSubBndrs IfaceClass { ifCtxt = sc_ctxt, 
-                               ifName = cls_occ, 
-                               ifSigs = sigs }
+ifaceDeclSubBndrs (IfaceClass {ifCtxt = sc_ctxt, ifName = cls_occ, 
+                              ifSigs = sigs, ifATs = ats })
   = co_occs ++
     [tc_occ, dc_occ, dcww_occ] ++
-    [op | IfaceClassOp op _ _ <- sigs] ++
+    [op | IfaceClassOp op  _ _ <- sigs] ++
+    [ifName at | at <- ats ] ++
     [mkSuperDictSelOcc n cls_occ | n <- [1..n_ctxt]] 
   where
     n_ctxt = length sc_ctxt

diff --git a/compiler/main/HscTypes.lhs b/compiler/main/HscTypes.lhs
index b142d19..e7df0ba 100644 (file)
--- a/compiler/main/HscTypes.lhs
+++ b/compiler/main/HscTypes.lhs
@@ -82,7 +82,7 @@ import CoreSyn                ( CoreBind )
 import Id              ( Id )
 import Type            ( TyThing(..) )
 
-import Class           ( Class, classSelIds, classTyCon )
+import Class           ( Class, classSelIds, classATs, classTyCon )
 import TyCon           ( TyCon, tyConSelIds, tyConDataCons, isNewTyCon,
                          newTyConCo_maybe, tyConFamilyCoercion_maybe )
 import DataCon         ( dataConImplicitIds )
@@ -634,10 +634,11 @@ implicitTyThings (ATyCon tc) = implicitCoTyCon tc ++
                                         (tyConDataCons tc)
                     
        -- For classes, add the class TyCon too (and its extras)
-       -- and the class selector Ids
+       -- and the class selector Ids and the associated types (they don't
+       -- have extras as these are only the family decls)
 implicitTyThings (AClass cl) = map AnId (classSelIds cl) ++
+                              map ATyCon (classATs cl) ++
                               extras_plus (ATyCon (classTyCon cl))
-                        
 
        -- For data cons add the worker and wrapper (if any)
 implicitTyThings (ADataCon dc) = map AnId (dataConImplicitIds dc)

diff --git a/compiler/typecheck/TcTyClsDecls.lhs b/compiler/typecheck/TcTyClsDecls.lhs
index 9065d28..c9dee4b 100644 (file)
--- a/compiler/typecheck/TcTyClsDecls.lhs
+++ b/compiler/typecheck/TcTyClsDecls.lhs
@@ -213,12 +213,20 @@ tcTyAndClassDecls boot_details allDecls
        -- Add the implicit things;
        -- we want them in the environment because 
        -- they may be mentioned in interface files
+       -- NB: All associated types and their implicit things will be added a
+       --     second time here.  This doesn't matter as the definitions are
+       --     the same.
        ; let { implicit_things = concatMap implicitTyThings alg_tyclss }
        ; traceTc ((text "Adding" <+> ppr alg_tyclss) 
                   $$ (text "and" <+> ppr implicit_things))
        ; tcExtendGlobalEnv implicit_things getGblEnv
     }}
   where
+    -- Pull associated types out of class declarations, to tie them into the
+    -- knot above.  
+    -- NB: We put them in the same place in the list as `tcTyClDecl' will
+    --    eventually put the matching `TyThing's.  That's crucial; otherwise,
+    --    the two argument lists of `mkGlobalThings' don't match up.
     addATs decl@(L _ (ClassDecl {tcdATs = ats})) = decl : ats
     addATs decl                                         = [decl]