[gcc r15-10329] ada: Fix crash on iterator of type with Constant_Indexing aspect

[Eric Botcazou]

https://gcc.gnu.org/g:6e1f5f7800194a2c9d66b7fb1736bfcb2edd8c8b

commit r15-10329-g6e1f5f7800194a2c9d66b7fb1736bfcb2edd8c8b
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Fri Aug 29 09:24:33 2025 +0200

    ada: Fix crash on iterator of type with Constant_Indexing aspect
    
    This happens when the type returned by the indexing function is a private
    type whose completion is derived from another private type, because the
    Finalize_Address routine cannot correctly fetch the actual root type.
    
    gcc/ada/ChangeLog:
    
            * exp_util.adb (Finalize_Address): In an untagged derivation, call
            Root_Type on the full view of the base type if the partial view is
            itself not a derived type.
            (Is_Untagged_Derivation): Minor formatting tweak.

Diff:
---
 gcc/ada/exp_util.adb | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index 5f644ef2503c..bfbbab78602e 100644
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -6080,7 +6080,11 @@ package body Exp_Util is
             Utyp := Corresponding_Record_Type (Root_Type (Btyp));
 
          elsif Is_Implicit_Full_View (Utyp) then
-            Utyp := Underlying_Type (Root_Type (Btyp));
+            if Is_Derived_Type (Btyp) then
+               Utyp := Underlying_Type (Root_Type (Btyp));
+            else
+               Utyp := Underlying_Type (Root_Type (Full_View (Btyp)));
+            end if;
 
             if Is_Protected_Type (Utyp) then
                Utyp := Corresponding_Record_Type (Utyp);
@@ -9907,7 +9911,8 @@ package body Exp_Util is
    begin
       return (not Is_Tagged_Type (T) and then Is_Derived_Type (T))
                or else
-                 (Is_Private_Type (T) and then Present (Full_View (T))
+                 (Is_Private_Type (T)
+                   and then Present (Full_View (T))
                    and then not Is_Tagged_Type (Full_View (T))
                    and then Is_Derived_Type (Full_View (T))
                    and then Etype (Full_View (T)) /= T);