diff --git a/liquidhaskell-boot/liquidhaskell-boot.cabal b/liquidhaskell-boot/liquidhaskell-boot.cabal
index bea61010bd..78b7561c4b 100644
--- a/liquidhaskell-boot/liquidhaskell-boot.cabal
+++ b/liquidhaskell-boot/liquidhaskell-boot.cabal
@@ -60,6 +60,7 @@ library
                       Language.Haskell.Liquid.Constraint.Types
                       Language.Haskell.Liquid.Constraint.Relational
                       Liquid.GHC.API
+                      Liquid.GHC.API.Compat
                       Liquid.GHC.API.Extra
                       Liquid.GHC.API.StableModule
                       Language.Haskell.Liquid.GHC.CoreToLogic
diff --git a/liquidhaskell-boot/src-ghc/Liquid/GHC/API.hs b/liquidhaskell-boot/src-ghc/Liquid/GHC/API.hs
index 1126b7cd4b..f42f39d19d 100644
--- a/liquidhaskell-boot/src-ghc/Liquid/GHC/API.hs
+++ b/liquidhaskell-boot/src-ghc/Liquid/GHC/API.hs
@@ -18,6 +18,7 @@ module Liquid.GHC.API (
   ) where
 
 import Liquid.GHC.API.Extra as Ghc
+import Liquid.GHC.API.Compat as Ghc
 
 import           GHC                  as Ghc
     ( Class
diff --git a/liquidhaskell-boot/src-ghc/Liquid/GHC/API/Compat.hs b/liquidhaskell-boot/src-ghc/Liquid/GHC/API/Compat.hs
new file mode 100644
index 0000000000..cf20c34fad
--- /dev/null
+++ b/liquidhaskell-boot/src-ghc/Liquid/GHC/API/Compat.hs
@@ -0,0 +1,15 @@
+module Liquid.GHC.API.Compat (
+    UniqueId
+  , toUniqueId
+  ) where
+
+import Data.Word (Word64)
+
+----------------------
+-- Uniques
+----------------------
+
+type UniqueId = Word64
+
+toUniqueId :: Word64 -> UniqueId
+toUniqueId = id
diff --git a/liquidhaskell-boot/src/Language/Haskell/Liquid/GHC/Misc.hs b/liquidhaskell-boot/src/Language/Haskell/Liquid/GHC/Misc.hs
index 9726e920f5..113bdcbcf8 100644
--- a/liquidhaskell-boot/src/Language/Haskell/Liquid/GHC/Misc.hs
+++ b/liquidhaskell-boot/src/Language/Haskell/Liquid/GHC/Misc.hs
@@ -105,11 +105,11 @@ maybeAuxVar s
         name = mkInternalName (mkUnique 'x' uid) occ noSrcSpan
         occ = mkVarOcc (T.unpack (symbolText sym))
 
-stringTyCon :: Char -> Word64 -> String -> TyCon
+stringTyCon :: Char -> UniqueId -> String -> TyCon
 stringTyCon = stringTyConWithKind anyTy
 
 -- FIXME: reusing uniques like this is really dangerous
-stringTyConWithKind :: Kind -> Char -> Word64 -> String -> TyCon
+stringTyConWithKind :: Kind -> Char -> UniqueId -> String -> TyCon
 stringTyConWithKind k c n s = Ghc.mkPrimTyCon name [] k []
   where
     name          = mkInternalName (mkUnique c n) occ noSrcSpan
@@ -508,8 +508,8 @@ takeModuleUnique = mungeNames tailName sepUnique   "takeModuleUnique: "
   where
     tailName msg = symbol . safeLast msg
 
-splitModuleUnique :: Symbol -> (Symbol, Word64)
-splitModuleUnique x = (dropModuleNamesAndUnique x, base62ToW (takeModuleUnique x))
+splitModuleUnique :: Symbol -> (Symbol, UniqueId)
+splitModuleUnique x = (dropModuleNamesAndUnique x, toUniqueId $ base62ToW (takeModuleUnique x))
 
 base62ToW :: Symbol -> Word64
 base62ToW s =  fromMaybe (errorstar "base62ToW Out Of Range") $ go (F.symbolText s)
diff --git a/liquidhaskell-boot/src/Language/Haskell/Liquid/Transforms/ANF.hs b/liquidhaskell-boot/src/Language/Haskell/Liquid/Transforms/ANF.hs
index 21e76e62fb..e3e3e0447a 100644
--- a/liquidhaskell-boot/src/Language/Haskell/Liquid/Transforms/ANF.hs
+++ b/liquidhaskell-boot/src/Language/Haskell/Liquid/Transforms/ANF.hs
@@ -11,7 +11,6 @@
 
 module Language.Haskell.Liquid.Transforms.ANF (anormalize) where
 
-import           Data.Word (Word64)
 import           Debug.Trace (trace)
 import           Prelude                          hiding (error)
 import           Language.Haskell.Liquid.GHC.TypeRep
@@ -355,7 +354,7 @@ freshNormalVar γ t = do
   let sp = Sp.srcSpan (aeSrcSpan γ)
   return (mkUserLocalOrCoVar (anfOcc i) u Ghc.ManyTy t sp)
 
-anfOcc :: Word64 -> OccName
+anfOcc :: UniqueId -> OccName
 anfOcc = mkVarOccFS . GM.symbolFastString . F.intSymbol F.anfPrefix
 
 data AnfEnv = AnfEnv