[gcc r13-836] [Ada] Fix expansion of aggregate for discriminated limited extension

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

https://gcc.gnu.org/g:567bf44932542b8f861dc7880dba3273fb5838ce

commit r13-836-g567bf44932542b8f861dc7880dba3273fb5838ce
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Sat Apr 23 12:28:28 2022 +0200

    [Ada] Fix expansion of aggregate for discriminated limited extension
    
    The presence of the discriminants prevents the values associated with the
    components of the parent type from being put into the sub-aggregate built
    for the _Parent component.
    
    gcc/ada/
    
            * exp_aggr.adb (Expand_Record_Aggregate.Build_Back_End_Aggregate):
            Skip the discriminants at the start of the component list before
            looking for the components inherited from the parent in the case
            of a tagged extension.

Diff:
---
 gcc/ada/exp_aggr.adb | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/gcc/ada/exp_aggr.adb b/gcc/ada/exp_aggr.adb
index 13be987b3e6..4828406647c 100644
--- a/gcc/ada/exp_aggr.adb
+++ b/gcc/ada/exp_aggr.adb
@@ -8474,11 +8474,21 @@ package body Exp_Aggr is
                   Parent_Name  : Node_Id;
 
                begin
-                  --  Remove the inherited component association from the
-                  --  aggregate and store them in the parent aggregate
-
                   First_Comp   := First (Component_Associations (N));
                   Parent_Comps := New_List;
+
+                  --  First skip the discriminants
+
+                  while Present (First_Comp)
+                    and then Ekind (Entity (First (Choices (First_Comp))))
+                                                               = E_Discriminant
+                  loop
+                     Next (First_Comp);
+                  end loop;
+
+                  --  Then remove the inherited component association from the
+                  --  aggregate and store them in the parent aggregate
+
                   while Present (First_Comp)
                     and then
                       Scope (Original_Record_Component