diff -r e77e8ef5bf9b -r 0ca0a47235e5 src/Tools/Code/code_haskell.ML
--- a/src/Tools/Code/code_haskell.ML	Mon Dec 23 21:22:10 2024 +0100
+++ b/src/Tools/Code/code_haskell.ML	Mon Dec 23 21:58:26 2024 +0100
@@ -330,6 +330,10 @@
   ("Maybe", ["Nothing", "Just"])
 ];
 
+val data_bits_import_operators = [
+  ".&.", ".|.", ".^."
+];
+
 fun serialize_haskell module_prefix string_classes ctxt { module_name,
     reserved_syms, identifiers, includes, class_syntax, tyco_syntax, const_syntax } program exports =
   let
@@ -379,7 +383,10 @@
       enclose "import Prelude (" ");" (commas (map str
         (map (Library.enclose "(" ")") prelude_import_operators @ prelude_import_unqualified)
           @ map (fn (tyco, constrs) => (enclose (tyco ^ "(") ")" o commas o map str) constrs) prelude_import_unqualified_constr))
+      :: enclose "import Data.Bits (" ");" (commas
+        (map (str o Library.enclose "(" ")") data_bits_import_operators))
       :: print_qualified_import "Prelude"
+      :: print_qualified_import "Data.Bits"
       :: map (print_qualified_import o fst) includes;
     fun print_module module_name (gr, imports) =
       let