Loosening requirements for super() invocation

[Archie Cobbs]

On Thu, Jan 26, 2023 at 11:25 AM Brian Goetz <brian.goetz at oracle.com> wrote:

> For example, would this be allowed?
>
> class A {
>     final int a;
>
>     A() { this.a = 0; }
> }
>
> class B extends A {
>     B() {
>         this.a = 1;
>         super();
>     }
> }
>

No, that's definitely not supposed to be allowed.


> The current draft JEP says it would:
>
> Add the following restrictions on constructors:
>     No access to this, other than assignments to fields, may occur unless
> this is DA
>
>
Thanks for pointing that out. I've updated the draft to say "other than
assignments to local fields".

So, its possible that #3 also has reasonable cost/benefit.  The current
> "pinch point" approach could probably be brought to bear on it with
> modifications, without having to thread everything through DA.  But I think
> there are subtleties to think through first.
>

I'm hopeful we can include #3 - I think it's important because it gives
users a way to address a problem that is all at once subtle, dangerous, and
difficult to avoid.

-Archie

-- 
Archie L. Cobbs
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