diff --git a/ghc-datasize.cabal b/ghc-datasize.cabal
--- a/ghc-datasize.cabal
+++ b/ghc-datasize.cabal
@@ -1,5 +1,5 @@
 name:               ghc-datasize
-version:            0.2.5
+version:            0.2.6
 license:            BSD3
 license-file:       LICENSE
 category:           GHC, Debug, Development
@@ -22,6 +22,7 @@
   Default-Language: Haskell2010
   Build-depends: base >= 4.12 && < 4.16,
                  deepseq >= 1.3 && < 1.5,
+                 ghc-heap >= 8.0 && < 9.0,
                  ghc-prim >= 0.5 && < 0.8
   Hs-source-dirs: src/
   Ghc-options: -Wall
diff --git a/src/GHC/DataSize.hs b/src/GHC/DataSize.hs
--- a/src/GHC/DataSize.hs
+++ b/src/GHC/DataSize.hs
@@ -17,8 +17,6 @@
 
 import Control.DeepSeq (NFData, ($!!))
 
-import Data.Word (Word)
-
 import GHC.Exts
 import GHC.Exts.Heap hiding (size)
 import GHC.Exts.Heap.Constants (wORD_SIZE)