https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119643
--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
Minimal kluge:
diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
index d4ab44fee92..0a9ef419db7 100644
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -9314,11 +9314,12 @@ package body Sem_Ch8 is
-- If the new type is a renaming of the old one, as is the case
-- for actuals in instances, retain its name, to simplify later
- -- disambiguation.
+ -- disambiguation. Beware of Natural and Positive, see Cstand.
if Nkind (Parent (New_T)) = N_Subtype_Declaration
and then Is_Entity_Name (Subtype_Indication (Parent (New_T)))
and then Entity (Subtype_Indication (Parent (New_T))) = Old_T
+ and then Scope (New_T) /= Standard_Standard
then
null;
else
