[Ada] Spurious visibility error in generic child unit

2019-09-19  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_ch7.adb (Install_Parent_Private_Declarations): If a
	generic child unit is instantiated within a sibling child unit,
	the analysis of its private part requires that the private part
	of the ancestor be available, as is done when the context
	includes an instance of the ancestor.

gcc/testsuite/

	* gnat.dg/generic2-child.ads, gnat.dg/generic2-io_any.adb,
	gnat.dg/generic2-io_any.ads, gnat.dg/generic2.ads: New testcase.

From-SVN: r275949

gcc/ada/ChangeLog

+2019-09-19  Ed Schonberg  <schonberg@adacore.com>
+
+	* sem_ch7.adb (Install_Parent_Private_Declarations): If a
+	generic child unit is instantiated within a sibling child unit,
+	the analysis of its private part requires that the private part
+	of the ancestor be available, as is done when the context
+	includes an instance of the ancestor.
+
 2019-09-19  Yannick Moy  <moy@adacore.com>
 
 	* inline.adb (Can_Be_Inlined_In_GNATprove_Mode): Add special

gcc/ada/sem_ch7.adb

@@ -1508,9 +1508,21 @@ package body Sem_Ch7 is
                   Inst_Par := Renamed_Entity (Inst_Par);
                end if;
 
-               Gen_Par :=
-                 Generic_Parent
-                   (Specification (Unit_Declaration_Node (Inst_Par)));
+               --  The instance may appear in a sibling generic unit, in
+               --  which case the prefix must include the common (generic)
+               --  ancestor, which is treated as a current instance.
+
+               if Inside_A_Generic
+                 and then Ekind (Inst_Par) = E_Generic_Package
+               then
+                  Gen_Par := Inst_Par;
+                  pragma Assert (In_Open_Scopes (Gen_Par));
+
+               else
+                  Gen_Par :=
+                    Generic_Parent
+                      (Specification (Unit_Declaration_Node (Inst_Par)));
+               end if;
 
                --  Install the private declarations and private use clauses
                --  of a parent instance of the child instance, unless the

gcc/testsuite/ChangeLog

+2019-09-19  Ed Schonberg  <schonberg@adacore.com>
+
+	* gnat.dg/generic2-child.ads, gnat.dg/generic2-io_any.adb,
+	gnat.dg/generic2-io_any.ads, gnat.dg/generic2.ads: New testcase.
+
 2019-09-19  Yannick Moy  <moy@adacore.com>
 
 	* gnat.dg/global2.adb, gnat.dg/global2.ads: New testcase.

gcc/testsuite/gnat.dg/generic2-child.ads

+generic
+package Generic2.Child is
+private
+  type My_Int is new Int;
+end Generic2.Child;

gcc/testsuite/gnat.dg/generic2-io_any.adb

+--  { dg-do compile }
+
+package body Generic2.IO_Any is
+  procedure Dummy is null;
+end Generic2.IO_Any;
\ No newline at end of file

gcc/testsuite/gnat.dg/generic2-io_any.ads

+with Generic2.Child;
+generic
+package Generic2.IO_Any is
+  package V1 is new Generic2.Child;
+  procedure Dummy;
+end Generic2.IO_Any;

gcc/testsuite/gnat.dg/generic2.ads

+generic
+package Generic2 is
+private
+  type Int is new Integer;
+end Generic2;