[Ada] Incorrect accessibility level on type in formal package

[Ada] Incorrect accessibility level on type in formal package

[Pierre-Marie de Rodat]

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This patch fixes an issue in the compiler whereby a class-wide allocator
for a type declared within a generic formal package was not treated the
same as a formal type with respect to accessibility checks - leading to
spurious accessibility errors.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* sem_util.adb, sem_util.ads (In_Generic_Formal_Package):
	Created to identify type declarations occurring within generic
	formal packages.
	* sem_res.adb (Resolve_Allocator): Add condition to avoid
	emitting an error for allocators when the type being allocated
	is class-wide and from a generic formal package.

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diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb
--- a/gcc/ada/sem_res.adb
+++ b/gcc/ada/sem_res.adb
@@ -5451,9 +5451,12 @@ package body Sem_Res is
 
                --  Do not apply Ada 2005 accessibility checks on a class-wide
                --  allocator if the type given in the allocator is a formal
-               --  type. A run-time check will be performed in the instance.
+               --  type or within a formal package. A run-time check will be
+               --  performed in the instance.
 
-               elsif not Is_Generic_Type (Exp_Typ) then
+               elsif not Is_Generic_Type (Exp_Typ)
+                 and then not In_Generic_Formal_Package (Exp_Typ)
+               then
                   Error_Msg_N
                     ("type in allocator has deeper level than designated "
                      & "class-wide type", E);


diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -13827,6 +13827,28 @@ package body Sem_Util is
           and then Assertion_Expression_Pragma (Get_Pragma_Id (Prag));
    end In_Assertion_Expression_Pragma;
 
+   -------------------------------
+   -- In_Generic_Formal_Package --
+   -------------------------------
+
+   function In_Generic_Formal_Package (E : Entity_Id) return Boolean is
+      Par : Node_Id;
+
+   begin
+      Par := Parent (E);
+      while Present (Par) loop
+         if Nkind (Par) = N_Formal_Package_Declaration
+           or else Nkind (Original_Node (Par)) = N_Formal_Package_Declaration
+         then
+            return True;
+         end if;
+
+         Par := Parent (Par);
+      end loop;
+
+      return False;
+   end In_Generic_Formal_Package;
+
    ----------------------
    -- In_Generic_Scope --
    ----------------------


diff --git a/gcc/ada/sem_util.ads b/gcc/ada/sem_util.ads
--- a/gcc/ada/sem_util.ads
+++ b/gcc/ada/sem_util.ads
@@ -1538,6 +1538,9 @@ package Sem_Util is
    --  Returns True if node N appears within a pragma that acts as an assertion
    --  expression. See Sem_Prag for the list of qualifying pragmas.
 
+   function In_Generic_Formal_Package (E : Entity_Id) return Boolean;
+   --  Returns True if entity E is inside a generic formal package
+
    function In_Generic_Scope (E : Entity_Id) return Boolean;
    --  Returns True if entity E is inside a generic scope