Create helper method for specializing type signatures.

1 files changed, 13 insertions, 5 deletions

diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs b/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs
index 109788fd..2295605b 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs
@@ -5,11 +5,7 @@
 
 
 module Haddock.Backends.Xhtml.Specialize
-    ( specialize, specialize'
-    , specializeTyVarBndrs
-    , specializePseudoFamilyDecl
-    , sugar, rename
-    , freeVariables
+    ( specializePseudoFamilyDecl, specializeSig
     ) where
 
 
@@ -80,6 +76,18 @@ specializePseudoFamilyDecl bndrs typs decl =
     specializeTyVars = specializeTyVarBndrs bndrs typs
 
 
+specializeSig :: (Eq name, Typeable name, DataId name, SetName name)
+              => LHsTyVarBndrs name -> [HsType name]
+              -> Sig name
+              -> Sig name
+specializeSig bndrs typs (TypeSig lnames (L loc typ) prn) =
+    TypeSig lnames (L loc typ') prn
+  where
+    typ' = rename fv . sugar $ specializeTyVarBndrs bndrs typs typ
+    fv = foldr Set.union Set.empty . map freeVariables $ typs
+specializeSig _ _ sig = sig
+
+
 -- | Make given type use tuple and list literals where appropriate.
 --
 -- After applying 'specialize' function some terms may not use idiomatic list