Rewrite findMeta in terms of listify.

It'll now recurse into the data item you give it, which means it works
on types like Actual where the Meta isn't an immediate child.

data/Metadata.hs

@@ -70,11 +70,9 @@ unpackMeta s
     getInt s = case readDec s of [(v, "")] -> v
 
 -- | Find the first Meta value in some part of the AST.
-findMeta :: (Data t, Typeable t) => t -> Meta
+-- Return 'emptyMeta' if it couldn't find one.
-findMeta e = case cast e of
+findMeta :: Data t => t -> Meta
-               Just m -> m
+findMeta e
-               Nothing -> if null (concat metaList) then emptyMeta else head (concat metaList)
+    = case listify (const True :: Meta -> Bool) e of
-  where
+        (m:_) -> m
-    metaList = gmapQ (mkQ [] findMeta') e
+        [] -> emptyMeta
-    findMeta' :: Meta -> [Meta]
-    findMeta' m = [m]