diff -r e4e643705d90 -r 559909bd7715 src/HOL/Library/code_test.ML
--- a/src/HOL/Library/code_test.ML	Mon Jun 10 14:04:52 2024 +0200
+++ b/src/HOL/Library/code_test.ML	Mon Jun 10 14:05:39 2024 +0200
@@ -131,7 +131,7 @@
     pretty_eval ctxt evals eval_ts)
 
 fun pretty_failures ctxt target failures =
-  Pretty.blk (0, Pretty.fbreaks (map (pretty_failure ctxt target) failures))
+  Pretty.block0 (Pretty.fbreaks (map (pretty_failure ctxt target) failures))
 
 
 (* driver invocation *)