Add testcase for private overrides in 'No_Inherited_Classwide_Pre'

Author: HugoGGuerrier

testsuite/tests/checks/no_inherited_classwide_pre/class.ads

@@ -10,11 +10,11 @@ package Class is
    type T is tagged private;
 
    type NT1 is new T and Int with private;
-   function Test (X : NT1) return Boolean;        --  FLAG
-   procedure Proc (X : in out NT1);               --  NOFLAG
+   function Test (X : NT1) return Boolean;   --  FLAG
+   procedure Proc (X : in out NT1);          --  NOFLAG
 
    type NT2 is new T and Int1 with private;
-   procedure Proc (X : in out NT2);               --  FLAG
+   procedure Proc (X : in out NT2);          --  FLAG
 
 private
    type T is tagged record
@@ -24,4 +24,7 @@ private
    type NT1 is new T and Int with null record;
    type NT2 is new T and Int1 with null record;
 
+   type PT is new T and Int1 with null record;
+   procedure Proc (X : in out PT) is null;   --  FLAG
+
 end Class;

testsuite/tests/checks/no_inherited_classwide_pre/test.out

@@ -3,10 +3,14 @@ class.adb:15:14: rule violation: overriding operation that does not inherit Pre'
    |              ^^^^
 
 class.ads:13:13: rule violation: overriding operation that does not inherit Pre'Class (class.ads:4:4)
-13 |    function Test (X : NT1) return Boolean;        --  FLAG
+13 |    function Test (X : NT1) return Boolean;   --  FLAG
    |             ^^^^
 
 class.ads:17:14: rule violation: overriding operation that does not inherit Pre'Class (class.ads:8:4)
-17 |    procedure Proc (X : in out NT2);               --  FLAG
+17 |    procedure Proc (X : in out NT2);          --  FLAG
+   |              ^^^^
+
+class.ads:28:14: rule violation: overriding operation that does not inherit Pre'Class (class.ads:8:4)
+28 |    procedure Proc (X : in out PT) is null;   --  FLAG
    |              ^^^^