From: squirek <squirek@adacore.com>
Date: Tue, 13 Aug 2024 12:06:52 +0000 (+0000)
Subject: ada: Spurious error on abstract primitive with access formals
X-Git-Tag: basepoints/gcc-16~4416
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9bba882f922e69abc72fa71520be649258cfd856;p=thirdparty%2Fgcc.git

ada: Spurious error on abstract primitive with access formals

This patch fixes an issue in the compiler whereby using anonymous access
types as abstract overridden subprogram formals for a derived abtract type
may lead to compile-time errors.

gcc/ada/ChangeLog:

	* accessibility.adb (Type_Access_Level): Add handling for
	subprogram aliases.
---

diff --git a/gcc/ada/accessibility.adb b/gcc/ada/accessibility.adb
index 298103377a7b..a4129819109d 100644
--- a/gcc/ada/accessibility.adb
+++ b/gcc/ada/accessibility.adb
@@ -2331,7 +2331,20 @@ package body Accessibility is
          return Scope_Depth (Standard_Standard);
       end if;
 
-      return Scope_Depth (Enclosing_Dynamic_Scope (Btyp));
+      --  It is possible that the current scope is an aliased subprogram -
+      --  this can happen when an abstract primitive from a root type is not
+      --  not visible.
+
+      if Is_Subprogram (Enclosing_Dynamic_Scope (Btyp))
+        and then Present (Alias (Enclosing_Dynamic_Scope (Btyp)))
+      then
+         return Scope_Depth (Ultimate_Alias (Enclosing_Dynamic_Scope (Btyp)));
+
+      --  Otherwise, simply use the enclosing dynamic scope
+
+      else
+         return Scope_Depth (Enclosing_Dynamic_Scope (Btyp));
+      end if;
    end Type_Access_Level;
 
 end Accessibility;