[Ada] AI12-0282: shared variable control aspects on formal types

2019-12-18  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* par-ch12.adb (P_Formal_Derived_Type_Definition): In Ada_2020
	the keyword WITH can indicate the start of aspect specifications
	and not a private type extension.
	* sem_ch12.adb (Analyze_Formal_Type): Indicate that it is a
	first subtype.
	(Instantiate_Type): New procedure
	Check_Shared_Variable_Control_Aspects to verify matching rules
	between formal and actual types. Note that an array type with
	aspect Atomic_Components is considered compatible with an array
	type whose component type is Atomic, even though the array types
	do not carry the same aspect.
	* sem_ch13.adb (Analyze_One_Aspect): Allow shared variable
	control aspects to appear on formal types.
	(Rep_Item_Too_Early): Exclude aspects on formal types.
	* sem_prag.adb (Mark_Type): Handle properly pragmas that come
	from aspects on formal types.
	(Analyze_Pragma, case Atomic_Components): Handle formal types.

From-SVN: r279512

1 files changed, 10 insertions, 3 deletions

diff --git a/gcc/ada/par-ch12.adb b/gcc/ada/par-ch12.adb
index 3216927..0ecac2e 100644
--- a/gcc/ada/par-ch12.adb
+++ b/gcc/ada/par-ch12.adb
@@ -971,9 +971,16 @@ package body Ch12 is
       end if;
 
       if Token = Tok_With then
-         Scan; -- past WITH
-         Set_Private_Present (Def_Node, True);
-         T_Private;
+
+         if Ada_Version >= Ada_2020 and Token /= Tok_Private then
+            --  Formal type has aspect specifications, parsed later.
+            return Def_Node;
+
+         else
+            Scan; -- past WITH
+            Set_Private_Present (Def_Node, True);
+            T_Private;
+         end if;
 
       elsif Token = Tok_Tagged then
          Scan;