[gcc r12-1678] [Ada] Skip overlay checks on protected components with expansion disabled

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

https://gcc.gnu.org/g:b1955e0e6dbcc376c8a05ea51751dcce7e210266

commit r12-1678-gb1955e0e6dbcc376c8a05ea51751dcce7e210266
Author: Piotr Trojanek <trojanek@adacore.com>
Date:   Fri Mar 26 09:02:33 2021 +0100

    [Ada] Skip overlay checks on protected components with expansion disabled
    
    gcc/ada/
    
            * sem_util.adb (Find_Overlaid_Entity): Ignore references to
            components and discriminants.

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

diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
index b59116e540b..2e102b93497 100644
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -9437,6 +9437,18 @@ package body Sem_Util is
 
          if Is_Entity_Name (Expr) then
             Ent := Entity (Expr);
+
+            --  If expansion is disabled, then we might see an entity of a
+            --  protected component or of a discriminant of a concurrent unit.
+            --  Ignore such entities, because further warnings for overlays
+            --  expect this routine to only collect entities of entire objects.
+
+            if Ekind (Ent) in E_Component | E_Discriminant then
+               pragma Assert
+                 (not Expander_Active
+                  and then Is_Concurrent_Type (Scope (Ent)));
+               Ent := Empty;
+            end if;
             return;
 
          --  Check for components