[gcc r13-534] [Ada] Take full view of private type

[Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>]

https://gcc.gnu.org/g:27b2b83bd7c1a9dfdba4ef27ea120ae5e1ead0b0

commit r13-534-g27b2b83bd7c1a9dfdba4ef27ea120ae5e1ead0b0
Author: Etienne Servais <servais@adacore.com>
Date:   Mon Feb 21 16:32:46 2022 +0100

    [Ada] Take full view of private type
    
    This allows to resolve the following:
    
          type Rec (<>) is private;
          type Arr (<>) is private;
       private
          type Arr is array (Positive range <>) of Natural;
          type Rec (L : Natural) is record
             F1 : Integer;
             F2 : Arr (1 .. L);
          end record;
    
    gcc/ada/
    
            * sem_ch3.adb (Analyze_Subtype_Declaration): Use underlying type
            of Indic_Typ.
            (Constrain_Array): Ditto for T.

Diff:
---
 gcc/ada/sem_ch3.adb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
index d2605f5a308..d41e27122f6 100644
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -5978,7 +5978,7 @@ package body Sem_Ch3 is
       if Nkind (Subtype_Indication (N)) = N_Subtype_Indication then
          declare
             Indic_Typ    : constant Entity_Id :=
-                             Etype (Subtype_Mark (Subtype_Indication (N)));
+              Underlying_Type (Etype (Subtype_Mark (Subtype_Indication (N))));
             Subt_Index   : Node_Id;
             Target_Index : Node_Id;
 
@@ -13595,6 +13595,8 @@ package body Sem_Ch3 is
          T := Designated_Type (T);
       end if;
 
+      T := Underlying_Type (T);
+
       --  If an index constraint follows a subtype mark in a subtype indication
       --  then the type or subtype denoted by the subtype mark must not already
       --  impose an index constraint. The subtype mark must denote either an