diff --git a/src/Language/Haskell/TH/TypeGraph/Orphans.hs b/src/Language/Haskell/TH/TypeGraph/Orphans.hs
--- a/src/Language/Haskell/TH/TypeGraph/Orphans.hs
+++ b/src/Language/Haskell/TH/TypeGraph/Orphans.hs
@@ -8,6 +8,9 @@
 module Language.Haskell.TH.TypeGraph.Orphans where
 
 import Data.Aeson (FromJSON(parseJSON), Value(Null), ToJSON(toJSON))
+#if MIN_VERSION_aeson(1,0,0)
+import Data.Aeson (ToJSONKey, FromJSONKey)
+#endif
 #if !MIN_VERSION_aeson(0,11,0)
 import Data.Aeson.Types (typeMismatch)
 #endif
diff --git a/src/Language/Haskell/TH/TypeGraph/Phantom.hs b/src/Language/Haskell/TH/TypeGraph/Phantom.hs
--- a/src/Language/Haskell/TH/TypeGraph/Phantom.hs
+++ b/src/Language/Haskell/TH/TypeGraph/Phantom.hs
@@ -1,5 +1,6 @@
 -- | Compute which type parameters are phantom types.
 
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE RecordWildCards #-}
@@ -76,9 +77,15 @@
     runQ (reify tname) >>= go
     where
       go :: DsMonad m => Info -> m [Type]
+#if MIN_VERSION_template_haskell(2,11,0)
+      go (TyConI (DataD _cx _tname binds _mkind _cons _supers)) = mapM (runQ . varT . toName) binds >>= go'
+      go (TyConI (NewtypeD _cx _tname binds _mkind _con _supers)) = mapM (runQ . varT . toName) binds >>= go'
+#else
       go (TyConI (DataD _cx _tname binds _cons _supers)) = mapM (runQ . varT . toName) binds >>= go'
       go (TyConI (NewtypeD _cx _tname binds _con _supers)) = mapM (runQ . varT . toName) binds >>= go'
+#endif
       go (TyConI (TySynD _tname binds _typ)) = mapM (runQ . varT . toName) binds >>= go'
+      go x = error $ "th-typegraph:nonPhantom - expecting TyConI DataD/TyConI NewtypeD/TyConI TySynD, but found " ++ show x
       go' :: DsMonad m => [Type] -> m [Type]
       go' ps =
           (Set.toList . view (_1 . result)) <$>
diff --git a/src/Language/Haskell/TH/TypeGraph/SafeCopyDerive.hs b/src/Language/Haskell/TH/TypeGraph/SafeCopyDerive.hs
--- a/src/Language/Haskell/TH/TypeGraph/SafeCopyDerive.hs
+++ b/src/Language/Haskell/TH/TypeGraph/SafeCopyDerive.hs
@@ -292,7 +292,7 @@
 #else
           safeCopyClass args = classP ''SafeCopy args
 #endif
-      in (:[]) <$> instanceD (cxt $ [safeCopyClass [varT $ var] | VarT var <- tyvars'] ++ map return context)
+      in (:[]) <$> instanceD (cxt $ [safeCopyClass [varT $ var] | VarT var <- tyvars'] ++ map return context ++ migrateFromKind ty kindName)
                                        (conT ''SafeCopy `appT` ty)
                                        [ mkPutCopy deriveType cons
                                        , mkGetCopy deriveType (show tyName) cons
@@ -300,6 +300,12 @@
                                        , valD (varP 'kind) (normalB (varE kindName)) []
                                        , funD 'errorTypeName [clause [wildP] (normalB $ litE $ StringL (show tyName)) []]
                                        ]
+    -- This adds Migrate Foo to the superclasses of SafeCopy Foo if
+    -- the kind is extension.  This lets us defer the actual
+    -- implementation of the Migrate instance, which is harmless and
+    -- sometimes useful.
+    migrateFromKind ty name =
+        if name == 'extension then [appT (conT ''Migrate) ty] else []
 
 internalDeriveSafeCopyIndexedType :: DeriveType -> Version a -> Name -> Name -> [Name] -> Q [Dec]
 internalDeriveSafeCopyIndexedType deriveType versionId kindName tyName tyIndex' = do
diff --git a/src/Language/Haskell/TH/TypeGraph/TypeTraversal.hs b/src/Language/Haskell/TH/TypeGraph/TypeTraversal.hs
--- a/src/Language/Haskell/TH/TypeGraph/TypeTraversal.hs
+++ b/src/Language/Haskell/TH/TypeGraph/TypeTraversal.hs
@@ -88,7 +88,7 @@
 doTypeOnce go typ = unvisited typ (go typ)
 
 doApply :: (HasTypeTraversal m, HasTypeParameters m, DsMonad m) => Type -> Type -> m ()
-doApply typ0 (ForallT tvs cxt typ) = doApply typ0 typ
+doApply typ0 (ForallT _tvs _cxt typ) = doApply typ0 typ
 doApply typ0 (VarT name) = doVarT typ0 name
 doApply typ0 (AppT a b) = pushParam b (doApply typ0 a)
 doApply typ0 (ConT tname) = qReify tname >>= doInfo typ0
@@ -138,7 +138,7 @@
                                  , _fieldName = Just fname
                                  , _fieldType = subst ftype' } in
              doField typ0 subst fld) (zip [1..] vsts)
-doCon typ0 tname subst cct cpos con@(NormalC cname sts) =
+doCon typ0 tname subst cct cpos (NormalC cname sts) =
   mapM_ (\(i, (_, ftype)) ->
              expandType ftype >>= \ftype' ->
              let fld = FieldInfo { _typeName = tname
diff --git a/th-typegraph.cabal b/th-typegraph.cabal
--- a/th-typegraph.cabal
+++ b/th-typegraph.cabal
@@ -1,5 +1,5 @@
 name:               th-typegraph
-version:            1.0
+version:            1.0.2
 cabal-version:      >= 1.10
 build-type:         Simple
 license:            BSD3