diff --git a/language-vhdl.cabal b/language-vhdl.cabal
--- a/language-vhdl.cabal
+++ b/language-vhdl.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                language-vhdl
-version:             0.1.2.1
+version:             0.1.2.2
 synopsis:            VHDL AST and pretty printer in Haskell.
 -- description:         
 license:             BSD3
diff --git a/src/Language/VHDL/Syntax.hs b/src/Language/VHDL/Syntax.hs
--- a/src/Language/VHDL/Syntax.hs
+++ b/src/Language/VHDL/Syntax.hs
@@ -2654,6 +2654,11 @@
   }
   deriving (Eq, Show)
 
+data LibraryUnit =
+    LibraryPrimary   PrimaryUnit
+  | LibrarySecondary SecondaryUnit
+  deriving (Eq, Show)
+
 data PrimaryUnit =
     PrimaryEntity  EntityDeclaration
   | PrimaryConfig  ConfigurationDeclaration
@@ -2794,9 +2799,6 @@
   deriving (Eq, Show)
 
 data LetterOrDigit = LetterOrDigit
-  deriving (Eq, Show)
-
-data LibraryUnit = LibraryUnit
   deriving (Eq, Show)
 
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