https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101515
--- Comment #6 from qinzhao at gcc dot gnu.org ---
the following patch fixed this bug:
[opc@qinzhao-aarch64-ol8 latest_gcc]$ git diff
diff --git a/gcc/cp/cxx-pretty-print.cc b/gcc/cp/cxx-pretty-print.cc
index 4f9a090e520d..744ed0add5ba 100644
--- a/gcc/cp/cxx-pretty-print.cc
+++ b/gcc/cp/cxx-pretty-print.cc
@@ -171,7 +171,10 @@ pp_cxx_unqualified_id (cxx_pretty_printer *pp, tree t)
case ENUMERAL_TYPE:
case TYPENAME_TYPE:
case UNBOUND_CLASS_TEMPLATE:
- pp_cxx_unqualified_id (pp, TYPE_NAME (t));
+ if (TYPE_NAME (t))
+ pp_cxx_unqualified_id (pp, TYPE_NAME (t));
+ else
+ pp_string (pp, "<unnamed type>");
if (tree ti = TYPE_TEMPLATE_INFO_MAYBE_ALIAS (t))
if (PRIMARY_TEMPLATE_P (TI_TEMPLATE (ti)))
{