diff --git a/Git/Tree/Builder.hs b/Git/Tree/Builder.hs
--- a/Git/Tree/Builder.hs
+++ b/Git/Tree/Builder.hs
@@ -7,6 +7,7 @@
        , mutateTree
        , mutateTreeOid
        , currentTree
+       , currentTreeOid
        , withTree
        , withTreeOid
        , dropEntry
diff --git a/Git/Types.hs b/Git/Types.hs
--- a/Git/Types.hs
+++ b/Git/Types.hs
@@ -293,6 +293,10 @@
 {- $references -}
 data RefTarget m = RefObj !(CommitOid m) | RefSymbolic !Text
 
+instance Repository m => Show (RefTarget m) where
+    show (RefObj coid) = "RefObj#" ++ T.unpack (renderObjOid coid)
+    show (RefSymbolic name) = "RefSymbolic#" ++ T.unpack name
+
 commitRefTarget :: Commit m -> RefTarget m
 commitRefTarget = RefObj . commitOid
 
@@ -403,7 +407,7 @@
                   | TreeEmptyCreateFailed
                   | CommitCreateFailed
                   | CommitLookupFailed Text
-                  | ReferenceCreateFailed
+                  | ReferenceCreateFailed Text
                   | ReferenceDeleteFailed Text
                   | RefCannotCreateFromPartialOid
                   | ReferenceListingFailed
diff --git a/gitlib.cabal b/gitlib.cabal
--- a/gitlib.cabal
+++ b/gitlib.cabal
@@ -1,5 +1,5 @@
 Name:                gitlib
-Version:             2.0.1.0
+Version:             2.0.1.1
 Synopsis:            API library for working with Git repositories
 License-file:        LICENSE
 License:             MIT