Mon Nov 20 20:50:19 UTC 2017

Repository : ssh://git@git.haskell.org/haddock

On branches: 2.17.3.1-spanfix,alexbiehl-patch-1,ghc-8.0,ghc-8.0-facebook,ghc-head,ghc-head1,haddock-quick,headdock-library-1.4.5,ie_avails,issue-303,issue-475,master,pr-filter-maps,pr/cabal-desc,travis,v2.16,v2.17,v2.17.3,v2.18,wip-located-module-as,wip/D2418,wip/T11080-open-data-kinds,wip/T11258,wip/T11430,wip/T12105,wip/T12105-2,wip/T12942,wip/T13163,wip/T3384,wip/embelleshed-rdr,wip/new-tree-one-param,wip/rae,wip/remove-frames,wip/remove-frames1,wip/revert-ttg-2017-11-20,wip/ttg-2017-10-13,wip/ttg-2017-10-31,wip/ttg-2017-11-06,wip/ttg2-2017-11-10,wip/ttg3-2017-11-12,wip/ttg4-constraints-2017-11-13
Link       : http://git.haskell.org/haddock.git/commitdiff/77b628b79bd179e7dde83d44bbea5acb4c0cb043

>---------------------------------------------------------------

commit 77b628b79bd179e7dde83d44bbea5acb4c0cb043
Author: Łukasz Hanuszczak <lukasz.hanuszczak at gmail.com>
Date:   Sun Jul 19 20:30:06 2015 +0200

    Create function for retrieving free variables from given type.


>---------------------------------------------------------------

77b628b79bd179e7dde83d44bbea5acb4c0cb043
 haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs b/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs
index 6a14971..7e56893 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs
@@ -159,6 +159,21 @@ renameType HsWildcardTy = pure HsWildcardTy
 renameType (HsNamedWildcardTy name) = HsNamedWildcardTy <$> renameName name
 
 
+freeVariables :: forall name. (NamedThing name, Data (HsType name))
+              => HsType name -> Set OccName
+freeVariables =
+    everythingWithState Set.empty Set.union query
+  where
+    query term ctx = case cast term :: Maybe (HsType name) of
+        Just (HsForAllTy _ _ bndrs _ _) ->
+            (Set.empty, Set.union ctx (bndrsNames bndrs))
+        Just (HsTyVar name)
+            | getName name `Set.member` ctx -> (Set.empty, ctx)
+            | otherwise -> (Set.singleton $ getOccName name, ctx)
+        _ -> (Set.empty, ctx)
+    bndrsNames = Set.fromList . map (getName . tyVarName . unLoc) . hsq_tvs
+
+
 renameLType :: SetName name => LHsType name -> Rename name (LHsType name)
 renameLType = located renameType
 
@@ -237,3 +252,8 @@ alternativeNames name =
 
 located :: Functor f => (a -> f b) -> Located a -> f (Located b)
 located f (L loc e) = L loc <$> f e
+
+
+tyVarName :: HsTyVarBndr name -> name
+tyVarName (UserTyVar name) = name
+tyVarName (KindedTyVar (L _ name) _) = name

