diff --git a/ghc/compiler/utils/StringBuffer.lhs b/ghc/compiler/utils/StringBuffer.lhs
index 0647cf35feddc24f90b2e40ddfe28c4967d5bb6a..c12aa2d9e1902b0ac627f16ea01b25a422f007a4 100644
--- a/ghc/compiler/utils/StringBuffer.lhs
+++ b/ghc/compiler/utils/StringBuffer.lhs
@@ -75,6 +75,9 @@ import Char (isDigit)
 # if __GLASGOW_HASKELL__ == 202
 import PrelBase ( Char(..) )
 # endif
+# if __GLASGOW_HASKELL__ >= 206
+import PackBase 
+# endif
 #endif
 import PrimPacked
 import FastString