diff -r fc8d64a578e4 -r 39df30349778 src/Tools/Code/code_printer.ML
--- a/src/Tools/Code/code_printer.ML	Thu Jun 23 21:25:56 2022 +0200
+++ b/src/Tools/Code/code_printer.ML	Thu Jun 23 21:50:32 2022 +0200
@@ -26,7 +26,7 @@
   val doublesemicolon: Pretty.T list -> Pretty.T
   val indent: int -> Pretty.T -> Pretty.T
   val markup_stmt: Code_Symbol.T -> Pretty.T -> Pretty.T
-  val format: Code_Symbol.T list -> int -> Pretty.T -> string
+  val format: Code_Symbol.T list -> int -> Pretty.T -> Bytes.T
 
   type var_ctxt
   val make_vars: string list -> var_ctxt
@@ -165,7 +165,7 @@
   #> YXML.parse_body
   #> filter_presentation presentation_names
   #> Buffer.add "\n"
-  #> Buffer.content;
+  #> Bytes.buffer;
 
 
 (** names and variable name contexts **)