[Ada] Pick volatile refinement property of a subtype from its base type

Volatile refinement properties (e.g. Async_Writers), which refine the
Volatile aspect in SPARK, are inherited by subtypes from their base
types. In particular, this patch fixes handling of those properties for
subtypes of private types.

gcc/ada/

	* sem_util.adb (Type_Or_Variable_Has_Enabled_Property): Given a
	subtype recurse into its base type.

diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
index 6cf3c70..b0cca08 100644 (file)
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -12683,7 +12683,8 @@ package body Sem_Util is
          then
             return False;
 
-         --  For a private type, may need to look at the full view
+         --  For a private type (including subtype of a private types), look at
+         --  the full view.
 
          elsif Is_Private_Type (Item_Id) and then Present (Full_View (Item_Id))
          then
@@ -12696,6 +12697,13 @@ package body Sem_Util is
             return Type_Or_Variable_Has_Enabled_Property
               (First_Subtype (Etype (Base_Type (Item_Id))));
 
+         --  For a subtype, the property will be inherited from its base type.
+
+         elsif Is_Type (Item_Id)
+           and then not Is_Base_Type (Item_Id)
+         then
+            return Type_Or_Variable_Has_Enabled_Property (Etype (Item_Id));
+
          --  If not specified explicitly for an object and its type
          --  is effectively volatile, then take result from the type.