diff --git a/safecopy.cabal b/safecopy.cabal
--- a/safecopy.cabal
+++ b/safecopy.cabal
@@ -7,7 +7,7 @@
 -- The package version. See the Haskell package versioning policy
 -- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
 -- standards guiding when and how versions should be incremented.
-Version:             0.8.4
+Version:             0.8.5
 
 -- A short (one-line) description of the package.
 Synopsis:            Binary serialization with version control.
diff --git a/src/Data/SafeCopy/Derive.hs b/src/Data/SafeCopy/Derive.hs
--- a/src/Data/SafeCopy/Derive.hs
+++ b/src/Data/SafeCopy/Derive.hs
@@ -375,10 +375,13 @@
                                return ( bindS (varP funVar) (varE baseFun) : ds
                                       , (t, funVar) : fs )
               where found = any ((== t) . fst) fs
+          finish
+            :: [(Type, Type)]            -- "dictionary" from synonyms(or not) to real types
+            -> ([StmtQ], [(Type, Name)]) -- statements
+            -> ([StmtQ], Type -> Name)   -- function body and name-generator
           finish typeList (ds, fs) = (reverse ds, getName)
               where getName typ = fromMaybe err $ lookup typ typeList >>= flip lookup fs
                     err = error "mkSafeFunctions: never here"
-    -- We can't use a Data.Map because Type isn't a member of Ord =/...
 
 -- | Follow type synonyms.  This allows us to see, for example,
 -- that @[Char]@ and @String@ are the same type and we just need
@@ -416,7 +419,7 @@
 typeName :: Type -> String
 typeName (VarT name) = nameBase name
 typeName (ConT name) = nameBase name
-typeName (TupleT n)  = '(' : replicate (n-1) ',' ++ ")"
+typeName (TupleT n)  = "Tuple" ++ show n
 typeName ArrowT      = "Arrow"
 typeName ListT       = "List"
 typeName (AppT t u)  = typeName t ++ typeName u