[Ada] Missing propagation of Has_Predicates in cloned subtypes

The frontend silently skips propagating attributes Has_Predicates and
Predicate function to the internally built cloned subtype. This change
does not affect the functionality of the compiler; it leaves more clean
the decoration of internal entities.

2019-09-17  Javier Miranda  <miranda@adacore.com>

gcc/ada/

	* sem_ch3.adb (Complete_Private_Subtype): Propagate attributes
	Has_Attributes and Predicate_Function to the cloned subtype.

From-SVN: r275795

gcc/ada/ChangeLog

+2019-09-17  Javier Miranda  <miranda@adacore.com>
+
+	* sem_ch3.adb (Complete_Private_Subtype): Propagate attributes
+	Has_Attributes and Predicate_Function to the cloned subtype.
+
 2019-09-17  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* sem.adb (Do_Analyze): Save Style_Check_Max_Line_Length on

gcc/ada/sem_ch3.adb

@@ -12509,6 +12509,18 @@ package body Sem_Ch3 is
          --  Show Full is simply a renaming of Full_Base
 
          Set_Cloned_Subtype (Full, Full_Base);
+
+         --  Propagate predicates
+
+         if Has_Predicates (Full_Base) then
+            Set_Has_Predicates (Full);
+
+            if Present (Predicate_Function (Full_Base))
+              and then No (Predicate_Function (Full))
+            then
+               Set_Predicate_Function (Full, Predicate_Function (Full_Base));
+            end if;
+         end if;
       end if;
 
       --  It is unsafe to share the bounds of a scalar type, because the Itype