[gcc r12-3748] [Ada] Set related expression for external DISCR symbols in Build_Temporary

[gcc r12-3748] [Ada] Set related expression for external DISCR symbols in Build_Temporary

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:900f9d999cc4870cc3cb70224e9694212385a4d3

commit r12-3748-g900f9d999cc4870cc3cb70224e9694212385a4d3
Author: Daniel Mercier <mercier@adacore.com>
Date:   Fri Jul 2 12:57:53 2021 +0200

    [Ada] Set related expression for external DISCR symbols in Build_Temporary
    
    gcc/ada/
    
            * exp_util.adb (Build_Temporary): In case of an external DISCR
            symbol, set the related expression for CodePeer so that a more
            comprehensible message can be emitted to the user.

Diff:
---
 gcc/ada/exp_util.adb | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index 96654815119..ad5a6fab2e9 100644
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -11656,6 +11656,7 @@ package body Exp_Util is
       is
          Temp_Id  : Entity_Id;
          Temp_Nam : Name_Id;
+         Should_Set_Related_Expression : Boolean := False;
 
       begin
          --  The context requires an external symbol : expression is
@@ -11675,6 +11676,12 @@ package body Exp_Util is
 
             else
                pragma Assert (Discr_Number > 0);
+
+               --  We don't have any intelligible way of printing T_DISCR in
+               --  CodePeer. Thus, set a related expression in this case.
+
+               Should_Set_Related_Expression := True;
+
                --  Use fully qualified name to avoid ambiguities.
 
                Temp_Nam :=
@@ -11684,6 +11691,10 @@ package body Exp_Util is
 
             Temp_Id := Make_Defining_Identifier (Loc, Temp_Nam);
 
+            if Should_Set_Related_Expression then
+               Set_Related_Expression (Temp_Id, Related_Nod);
+            end if;
+
          --  Otherwise generate an internal temporary
 
          else