Fixes to datacon wrappers for indexed data types

[ghc-hetmet.git] / compiler / types / TyCon.lhs

diff --git a/compiler/types/TyCon.lhs b/compiler/types/TyCon.lhs
index 8b2b24c..dfbf02c 100644 (file)
--- a/compiler/types/TyCon.lhs
+++ b/compiler/types/TyCon.lhs
@@ -203,10 +203,11 @@ data AlgTyConRhs
   | OpenTyCon {
 
       otArgPoss   :: Maybe [Int],  
-       -- for associated families: for each tyvar in the AT decl, gives the
-       -- position of that tyvar in the class argument list (starting from 0).
-       -- NB: Length is less than tyConArity iff higher kind signature.
-       -- NB: Just _ <=> associated (not toplevel) family
+       -- Nothing <=> top-level indexed type family
+       -- Just ns <=> associated (not toplevel) family
+       --   In the latter case, for each tyvar in the AT decl, 'ns' gives the
+       --   position of that tyvar in the class argument list (starting from 0).
+       --   NB: Length is less than tyConArity iff higher kind signature.
        
       otIsNewtype :: Bool           
         -- is a newtype (rather than data type)?
@@ -274,15 +275,16 @@ data AlgTyConParent
 
   | FamilyTyCon                -- Type constructors representing an instance of a type
        TyCon           --   The type family
-       [Type]          --   Instance types
+       [Type]          --   Instance types; free variables are the tyConTyVars
+                       --      of this TyCon
        TyCon           --   A CoercionTyCon identifying the representation 
                        --     type with the type instance family.  
                        --      c.f. Note [Newtype coercions]
        -- E.g.  data intance T [a] = ...
        -- gives a representation tycon:
-       --      data T77 a = ...
-       --      axiom co a :: T [a] ~ T77 a
-       -- with T77's algTcParent = FamilyTyCon T [a] co
+       --      data :R7T a = ...
+       --      axiom co a :: T [a] ~ :R7T a
+       -- with :R7T's algTcParent = FamilyTyCon T [a] co
 
 data SynTyConRhs
   = OpenSynTyCon Kind          -- Type family: *result* kind given