[Ada] Fix propagation of compiler internal flag

No change in behavior for GCC-based compilations.

2019-08-20  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_ch3.adb (Analyze_Object_Declaration): If actual type is
	private and distinct from nominal type in declaration, propagate
	flags Is_Constr_Subt_For_U_Nominal and _UN_Aliased to full view
	of private type.

From-SVN: r274735

gcc/ada/ChangeLog

 2019-08-20  Ed Schonberg  <schonberg@adacore.com>
 
+	* sem_ch3.adb (Analyze_Object_Declaration): If actual type is
+	private and distinct from nominal type in declaration, propagate
+	flags Is_Constr_Subt_For_U_Nominal and _UN_Aliased to full view
+	of private type.
+
+2019-08-20  Ed Schonberg  <schonberg@adacore.com>
+
 	* exp_attr.adb (Expand_Loop_Entry_Attribute): When expanding a
 	loop entry attribute for a while_loop we construct a function
 	that incorporates the expanded condition of the loop. The itypes

gcc/ada/sem_ch3.adb

@@ -3923,6 +3923,7 @@ package body Sem_Ch3 is
       --  Save the Ghost-related attributes to restore on exit
 
       Related_Id : Entity_Id;
+      Full_View_Present : Boolean := False;
 
    --  Start of processing for Analyze_Object_Declaration
 
@@ -4645,10 +4646,25 @@ package body Sem_Ch3 is
                Act_T := Find_Type_Of_Object (Object_Definition (N), N);
             end if;
 
+            --  Propagate attributes to full view when needed.
+
             Set_Is_Constr_Subt_For_U_Nominal (Act_T);
 
+            if Is_Private_Type (Act_T) and then Present (Full_View (Act_T))
+            then
+               Full_View_Present := True;
+            end if;
+
+            if Full_View_Present then
+               Set_Is_Constr_Subt_For_U_Nominal (Full_View (Act_T));
+            end if;
+
             if Aliased_Present (N) then
                Set_Is_Constr_Subt_For_UN_Aliased (Act_T);
+
+               if Full_View_Present then
+                  Set_Is_Constr_Subt_For_UN_Aliased (Full_View (Act_T));
+               end if;
             end if;
 
             Freeze_Before (N, Act_T);