X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FInstEnv.lhs;h=7327992540cfc29a65e8b861074568d547cd6fda;hb=5289f5d85610f71625a439747a09384876655eb5;hp=b3d8dccc536d300798ec5f6276d460db40d405a6;hpb=72462499b891d5779c19f3bda03f96e24f9554ae;p=ghc-hetmet.git

diff --git a/compiler/types/InstEnv.lhs b/compiler/types/InstEnv.lhs
index b3d8dcc..7327992 100644
--- a/compiler/types/InstEnv.lhs
+++ b/compiler/types/InstEnv.lhs
@@ -45,7 +45,6 @@ import Data.Maybe	( isJust, isNothing )
 %************************************************************************
 
 \begin{code}
-type DFunId = Id
 data Instance 
   = Instance { is_cls  :: Name		-- Class name
 	
@@ -59,7 +58,7 @@ data Instance
 		-- INVARIANT: is_dfun Id has type 
 		--	forall is_tvs. (...) => is_cls is_tys
 
-	     , is_dfun :: DFunId
+	     , is_dfun :: DFunId -- See Note [Haddock assumptions]
 	     , is_flag :: OverlapFlag	-- See detailed comments with
 					-- the decl of BasicTypes.OverlapFlag
     }
@@ -99,7 +98,20 @@ However, note that:
    (This is so that we can use the matching substitution to
     instantiate the dfun's context.)
 
+Note [Haddock assumptions]
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+For normal user-written instances, Haddock relies on
 
+ * the SrcSpan of
+ * the Name of
+ * the is_dfun of
+ * an Instance
+
+being equal to
+
+  * the SrcSpan of
+  * the instance head type of
+  * the InstDecl used to construct the Instance.
 
 \begin{code}
 instanceDFunId :: Instance -> DFunId
@@ -528,7 +540,7 @@ insert_overlapping new_item (item:items)
 \begin{code}
 instanceBindFun :: TyVar -> BindFlag
 instanceBindFun tv | isTcTyVar tv && isExistentialTyVar tv = Skolem
-	           | otherwise	 		 	= BindMe
+	           | otherwise	 		 	   = BindMe
    -- Note [Binding when looking up instances]
 \end{code}