Index: sem_ch4.adb
===================================================================
--- sem_ch4.adb	(revision 223754)
+++ sem_ch4.adb	(working copy)
@@ -4102,7 +4102,8 @@
       --  searches have failed. If a match is found, the Etype of both N and
       --  Sel are set from this component, and the entity of Sel is set to
       --  reference this component. If no match is found, Entity (Sel) remains
-      --  unset.
+      --  unset. For a derived type that is an actual of the instance, the
+      --  desired component may be found in any ancestor.
 
       function Has_Mode_Conformant_Spec (Comp : Entity_Id) return Boolean;
       --  It is known that the parent of N denotes a subprogram call. Comp
@@ -4117,18 +4118,36 @@
 
       procedure Find_Component_In_Instance (Rec : Entity_Id) is
          Comp : Entity_Id;
+         Typ  : Entity_Id;
 
       begin
-         Comp := First_Component (Rec);
-         while Present (Comp) loop
-            if Chars (Comp) = Chars (Sel) then
-               Set_Entity_With_Checks (Sel, Comp);
-               Set_Etype (Sel, Etype (Comp));
-               Set_Etype (N,   Etype (Comp));
+         Typ := Rec;
+         while Present (Typ) loop
+            Comp := First_Component (Typ);
+            while Present (Comp) loop
+               if Chars (Comp) = Chars (Sel) then
+                  Set_Entity_With_Checks (Sel, Comp);
+                  Set_Etype (Sel, Etype (Comp));
+                  Set_Etype (N,   Etype (Comp));
+                  return;
+               end if;
+
+               Next_Component (Comp);
+            end loop;
+
+            --  If not found, the component may be declared in the parent
+            --  type or its full view, if any.
+
+            if Is_Derived_Type (Typ) then
+               Typ := Etype (Typ);
+
+               if Is_Private_Type (Typ) then
+                  Typ := Full_View (Typ);
+               end if;
+
+            else
                return;
             end if;
-
-            Next_Component (Comp);
          end loop;
 
          --  If we fall through, no match, so no changes made
@@ -4789,6 +4808,18 @@
                      Par := Etype (Par);
                   end loop;
 
+               --  Another special case: the type is an extension of a private
+               --  type T, is an actual in an instance, and we are in the body
+               --  of the instance, so the generic body had a full view of the
+               --  type declaration for T or of some ancestor that defines the
+               --  component in question.
+
+               elsif Is_Derived_Type (Type_To_Use)
+                 and then Used_As_Generic_Actual (Type_To_Use)
+                 and then In_Instance_Body
+               then
+                  Find_Component_In_Instance (Parent_Subtype (Type_To_Use));
+
                --  In ASIS mode the generic parent type may be absent. Examine
                --  the parent type directly for a component that may have been
                --  visible in a parent generic unit.