Re: compiler hangs on circular type dependency

["James S. Rogers" <jimmaureenrogers@worldnet.att.net>]

"Victor Porton" <porton@ex-code.com> wrote in message
news:3e2cb563$0$33929$bed64819@news.gradwell.net...
> This is sent to report@gnat.com and duplicated in comp.lang.ada
>
> Gnat (both 3.14 and 3.15) hangs on compiling the following
> (erraneous) stuff:
>
> package P is
>     type A is tagged null record;
>     type B is new A with private;
>     type C is new A with private;
> private
>     type B is new C with null record;
>     type C is new B with null record;
> end P;
>
> BTW, comp.lang.ada, what in Ada Standard deprecated such circularity?
> Isn't it forgotten in the Standard itself?

No, this is clearly covered in the standard:

Section 3.4 paragraph 4 states:

A type shall be completely defined (see 3.11.1) prior to being specified
as the parent type in a derived_type_definition - the
full_type_declarations for the parent type and any of its
subcomponents have to precede the derived_type_definition.

Your private definitions violate this rule.

Jim Rogers