diff -r 3668aec7afa2 -r 7f9e8516ca05 src/Pure/Syntax/syntax_phases.ML
--- a/src/Pure/Syntax/syntax_phases.ML	Sun Sep 29 14:55:49 2024 +0200
+++ b/src/Pure/Syntax/syntax_phases.ML	Sun Sep 29 15:00:20 2024 +0200
@@ -185,7 +185,8 @@
     fun asts_of_position c tok =
       [Ast.Appl [Ast.Constant c, ast_of (Parser.Tip tok), ast_of_position tok]]
 
-    and asts_of (Parser.Node ("_class_name", [Parser.Tip tok])) =
+    and asts_of (Parser.Markup (markup, pts)) = maps asts_of pts
+      | asts_of (Parser.Node ("_class_name", [Parser.Tip tok])) =
           let
             val pos = report_pos tok;
             val (c, rs) = Proof_Context.check_class ctxt (Lexicon.str_of_token tok, pos);