Re: Odd subtyping error.

[Adam Beneschan <adam@irvine.com>]

On Friday, October 5, 2012 2:00:53 PM UTC-7, Shark8 wrote:
> Package Subtype_Error is
> 
> 	Type Base_Type is (
> 		   Item_1, Item_2, Item_3, Item_4, Item_5
> 		   ) with Size => Integer'Size;
> 
> 	SubType Derived_Type is Base_Type Range Item_2..Item_4;
>     Private
> 	For Base_Type Use
> 	  (
> 		Item_1	=> 18,
> 		Item_2	=> 21,
> 		Item_3	=> 22,
> 		Item_4	=> 25,
> 		Item_5	=> 28
>    	  );
>     End Subtype_Error;

Ah, "the rest of the story"!  The size clause isn't the problem.  The problem is that referring to Item_2 and Item_4 in the declaration of Derived_Type freezes Base_Type, and you can't add any more representation information after that.  That makes "For Base_Type Use ..." illegal.  If the error messages in your original case pointed you to the wrong line numbers, that's something you can complain to the GNAT folks about.  But the error is legitimate, at least in your reduced source.

                              -- Adam