[gcc r15-1522] ada: Crash when using user defined string literals

[Marc Poulhi?s]

https://gcc.gnu.org/g:96e037bcd160d2f63a04de09f2d47ed9aae082ad

commit r15-1522-g96e037bcd160d2f63a04de09f2d47ed9aae082ad
Author: Javier Miranda <miranda@adacore.com>
Date:   Thu Jun 6 11:20:14 2024 +0000

    ada: Crash when using user defined string literals
    
    When a non-overridable aspect is explicitly specified for a
    non-tagged derived type, the compiler blows up processing an
    object declaration of an object of such type.
    
    gcc/ada/
    
            * sem_ch13.adb (Analyze_One_Aspect): Fix code locating the entity
            of the parent type.

Diff:
---
 gcc/ada/sem_ch13.adb | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/sem_ch13.adb b/gcc/ada/sem_ch13.adb
index a86f774018a3..90376f818a30 100644
--- a/gcc/ada/sem_ch13.adb
+++ b/gcc/ada/sem_ch13.adb
@@ -4801,8 +4801,14 @@ package body Sem_Ch13 is
               and then Nkind (Type_Definition (N)) = N_Derived_Type_Definition
               and then not In_Instance_Body
             then
+               --  In order to locate the parent type we must go first to its
+               --  base type because the frontend introduces an implicit base
+               --  type even if there is no constraint attached to it, since
+               --  this is closer to the Ada semantics.
+
                declare
-                  Parent_Type      : constant Entity_Id := Etype (E);
+                  Parent_Type      : constant Entity_Id :=
+                    Etype (Base_Type (E));
                   Inherited_Aspect : constant Node_Id :=
                     Find_Aspect (Parent_Type, A_Id);
                begin