[COMMITTED] ada: Propagate aspect Ghost when instantiating null formal procedures

["Marc Poulhiès" <poulhies@adacore.com>]

From: Piotr Trojanek <trojanek@adacore.com>

When instantiating generic package that includes a formal subprogram
declaration with Ghost aspect and a subprogram_default of null, e.g.:

   generic
     with procedure Proc is null with Ghost;
   package P is ...

the Ghost aspect should be propagated to the internally generated null
subprogram, so this null subprogram can be used in contexts that require
ghost entities.

gcc/ada/

	* sem_ch12.adb (Instantiate_Formal_Subprogram): Copy aspect Ghost
	from formal subprogram declaration to the internally generated
	procedure.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/sem_ch12.adb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/ada/sem_ch12.adb b/gcc/ada/sem_ch12.adb
index ca0f4913e36..276656085be 100644
--- a/gcc/ada/sem_ch12.adb
+++ b/gcc/ada/sem_ch12.adb
@@ -11088,6 +11088,8 @@ package body Sem_Ch12 is
 
          Set_Convention (Defining_Unit_Name (New_Spec), Convention_Intrinsic);
 
+         Copy_Ghost_Aspect (Formal, To => Decl_Node);
+
          --  Eliminate the calls to it when optimization is enabled
 
          Set_Is_Inlined (Defining_Unit_Name (New_Spec));
-- 
2.34.1