Flexible constructors: dubious error

[Stephan Herrmann]

Thanks, Archie,

What you say effectively confirms my understanding that the error against access 
of 's' is good, the others are wrong.

What I said about not being an specification thing is that the spec does not 
mandate where exactly which synthetic argument / field is to be generated.

thanks,
Stephan

Am 29.10.24 um 15:24 schrieb Archie Cobbs:
> Hi Stephan,
> 
> On Tue, Oct 29, 2024 at 9:11 AM Stephan Herrmann <stephan.herrmann at berlin.de 
> <mailto:stephan.herrmann at berlin.de>> wrote:
> 
>     Am 29.10.24 um 14:11 schrieb Olexandr Rotan:
>      > Local classes, as well as inner ones (don't confuse with nested)
>     implicitly take
>      > parents "this" as a constructor argument
> 
>     They *may* take this argument *if needed*.
> 
>     But this is more an implementation detail and not the level at which the
>     specification defines this, is it?
> 
> 
> This is a specification thing.
> 
> Here is what is "supposed" to happen: Both "Local" classes in the example are 
> declared prior to super(). These classes are therefore within an early 
> construction context of "Inner" and therefore do not have access to the current 
> instance of "Inner" - but this access would be required for the expression "s" 
> which is short-hand for "Inner.this.s".
> 
> So the reference to "s" should generate an error, which happens with the current 
> 24 build:
> 
>      X.java:14: error: cannot reference s before supertype constructor has been 
> called
>                                                  System.out.println(s);
>                                                                     ^
> 
> FYI there is still an outstanding bug and associated PR 
> <https://github.com/openjdk/jdk/pull/21410> related to this situation, so with 
> the current 24 build you also get these (bogus) errors:
> 
>      X.java:7: error: cannot reference this before supertype constructor has 
> been called
>                                  new Local() {};
>                                              ^
>      X.java:12: error: cannot reference this before supertype constructor has 
> been called
>                                  new Local() {
>                                              ^
> 
> Those errors are bogus, because under the latest "flexible constructors" spec, 
> local classes declared in an early construction context of class C are treated 
> the same as anonymous classes in that situation - they do not have any outer 
> instance of type C - so you can declare and instantiate them freely.
> 
> -Archie
> 
> -- 
> Archie L. Cobbs