[COMMITTED] ada: Fix internal error on Big_Integer conversion ghost instance

[COMMITTED] ada: Fix internal error on Big_Integer conversion ghost instance

[Marc Poulhiès]

From: Eric Botcazou <ebotcazou@adacore.com>

The problem is that the ghost mode of the instance is used to analyze the
parent of the generic body, whose own ghost mode has nothing to do with it.

gcc/ada/

	* sem_ch12.adb (Instantiate_Package_Body): Set the ghost mode to
	that of the instance only after loading the generic's parent.
	(Instantiate_Subprogram_Body): Likewise.

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

---
 gcc/ada/sem_ch12.adb | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/gcc/ada/sem_ch12.adb b/gcc/ada/sem_ch12.adb
index 4fefcc8fb46..a9a3e322917 100644
--- a/gcc/ada/sem_ch12.adb
+++ b/gcc/ada/sem_ch12.adb
@@ -11911,12 +11911,6 @@ package body Sem_Ch12 is
          return;
       end if;
 
-      --  The package being instantiated may be subject to pragma Ghost. Set
-      --  the mode now to ensure that any nodes generated during instantiation
-      --  are properly marked as Ghost.
-
-      Set_Ghost_Mode (Act_Decl_Id);
-
       Expander_Mode_Save_And_Set (Body_Info.Expander_Status);
 
       --  Re-establish the state of information on which checks are suppressed.
@@ -12029,6 +12023,12 @@ package body Sem_Ch12 is
          Instantiation_Node := Inst_Node;
       end if;
 
+      --  The package being instantiated may be subject to pragma Ghost. Set
+      --  the mode now to ensure that any nodes generated during instantiation
+      --  are properly marked as Ghost.
+
+      Set_Ghost_Mode (Act_Decl_Id);
+
       if Present (Gen_Body_Id) then
          Save_Env (Gen_Unit, Act_Decl_Id);
          Style_Check := False;
@@ -12468,12 +12468,6 @@ package body Sem_Ch12 is
          return;
       end if;
 
-      --  The subprogram being instantiated may be subject to pragma Ghost. Set
-      --  the mode now to ensure that any nodes generated during instantiation
-      --  are properly marked as Ghost.
-
-      Set_Ghost_Mode (Act_Decl_Id);
-
       Expander_Mode_Save_And_Set (Body_Info.Expander_Status);
 
       --  Re-establish the state of information on which checks are suppressed.
@@ -12511,6 +12505,12 @@ package body Sem_Ch12 is
 
       Instantiation_Node := Inst_Node;
 
+      --  The subprogram being instantiated may be subject to pragma Ghost. Set
+      --  the mode now to ensure that any nodes generated during instantiation
+      --  are properly marked as Ghost.
+
+      Set_Ghost_Mode (Act_Decl_Id);
+
       if Present (Gen_Body_Id) then
          Gen_Body := Unit_Declaration_Node (Gen_Body_Id);
 
-- 
2.40.0