[gcc(refs/users/guojiufu/heads/guojiufu-branch)] [Ada] Fix small oversight in latest change for Replace_Discriminants

[Jiu Fu Guo <guojiufu@gcc.gnu.org>]

https://gcc.gnu.org/g:663091bc782563d7d9adc8b09e58afbac3656d13

commit 663091bc782563d7d9adc8b09e58afbac3656d13
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Fri Dec 13 16:57:46 2019 +0100

    [Ada] Fix small oversight in latest change for Replace_Discriminants
    
    2020-06-02  Eric Botcazou  <ebotcazou@adacore.com>
    
    gcc/ada/
    
            * sem_ch3.adb (Replace_Discriminants): Preserve the Etype of the
            Name of N_Variant_Part nodes when rewriting it.

Diff:
---
 gcc/ada/sem_ch3.adb | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
index e792072b45f..3fa2dd8e7a1 100644
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -22334,7 +22334,18 @@ package body Sem_Ch3 is
                if Original_Record_Component (Comp) = Entity (Name (N))
                  or else Chars (Comp) = Chars (Name (N))
                then
-                  Set_Name (N, New_Occurrence_Of (Comp, Sloc (N)));
+                  --  Make sure to preserve the type coming from the parent on
+                  --  the Name, even if the subtype of the discriminant can be
+                  --  constrained, so that discrete choices inherited from the
+                  --  parent in the variant part are not flagged as violating
+                  --  the constraints of the subtype.
+
+                  declare
+                     Typ : constant Entity_Id := Etype (Name (N));
+                  begin
+                     Rewrite (Name (N), New_Occurrence_Of (Comp, Sloc (N)));
+                     Set_Etype (Name (N), Typ);
+                  end;
                   exit;
                end if;