Change the representation of DocNames

Ross Paterson reported a bug where links would point to the defining module
instead of the "best" module for an identifier (e.g Int pointing to GHC.Base
instead of Data.Int). This patch fixes this problem by refactoring the way
renamed names are represented. Instead of representing them by:

> data DocName = Link Name | NoLink Name

they are now represented as such:

> data DocName = Documented Name Module | Undocumented Name

and the the link-env looks like this:

> type LinkEnv = Map Name Module

There are several reasons for this. First of all, the bug was caused by
changing the module part of Names during the renaming process, without changing
the Unique field. This caused names to be overwritten during the loading of
.haddock files (which caches names using the NameCache of the GHC session).
So we might create new Uniques during renaming to fix this (but I'm not
sure that would be problem-free). Instead, we just keep the Name and add the
Module where the name is best documented, since it can be useful to keep
the original Name around (for e.g. source-code location info and for users of
the Haddock API).

Also, the names Link/NoLink don't really make sense, since wether to use
links or not is entirely up to the users of DocName.

In the process of following this change into H.Backends.Html I removed the
assumption that binder names are Undocumented (which was just an unnecessary
assumption, the OccName is the only thing needed to render these). This will
probably make it possible to get rid of the renamer and replace it with a
traversal from SYB or Uniplate.

Since DocName has changed, InterfaceFile has changed so this patch also
increments the file-format version. No backwards-compatibility is implemented.

1 files changed, 9 insertions, 10 deletions

diff --git a/src/Haddock/Interface.hs b/src/Haddock/Interface.hs
index 5f40422e..51d8de2c 100644
--- a/src/Haddock/Interface.hs
+++ b/src/Haddock/Interface.hs
@@ -14,6 +14,7 @@ module Haddock.Interface (
 ) where
 
 
+import Haddock.DocName
 import Haddock.Interface.Create
 import Haddock.Interface.AttachInstances
 import Haddock.Interface.Rename
@@ -74,17 +75,15 @@ createInterfaces' modules flags = do
 -- The interfaces are passed in in topologically sorted order, but we start
 -- by reversing the list so we can do a foldl.
 buildHomeLinks :: [Interface] -> LinkEnv
-buildHomeLinks modules = foldl upd Map.empty (reverse modules)
+buildHomeLinks ifaces = foldl upd Map.empty (reverse ifaces)
   where
-    upd old_env mod
-      | OptHide    `elem` ifaceOptions mod = old_env
-      | OptNotHome `elem` ifaceOptions mod =
+    upd old_env iface
+      | OptHide    `elem` ifaceOptions iface = old_env
+      | OptNotHome `elem` ifaceOptions iface =
         foldl' keep_old old_env exported_names
       | otherwise = foldl' keep_new old_env exported_names
       where
-        exported_names = ifaceVisibleExports mod
-        modName = ifaceMod mod
-
-        keep_old env n = Map.insertWith (\new old -> old) n
-                         (nameSetMod n modName) env
-        keep_new env n = Map.insert n (nameSetMod n modName) env
+        exported_names = ifaceVisibleExports iface
+        mod            = ifaceMod iface
+        keep_old env n = Map.insertWith (\new old -> old) n mod env
+        keep_new env n = Map.insert n mod env