known translation issues related to JEP 482

[Maurizio Cimadamore]

Ok.

This is an attempt I made to fix the enclosing instance issue. It sits 
on top of the patch I shared yestreday, but probably could be integrated 
independently:

https://github.com/mcimadamore/jdk/compare/cleanup_capture...mcimadamore:jdk:cleanup_capture+encl_fix?expand=1

The core of the fix is the addition of a new function in `Symbol`, 
namely `Symbol::innermostAccessibleEnclosingClass`. As the name implies, 
the goal of this function is to return the class symbol corresponding to 
the innermost enclosing type that is accessible from the symbol's class.

This is used by `Lower` to determine the type of `this$0`, which allows 
us to construct a chain of enclosing instances that skips over all the 
inaccessible types.

I've also updated the `Symbol::hasOuterInstance` method, so that it, 
too, will skip over inaccessible enclosing type (and only return `true` 
if some accessible enclosing type is found).

Again, the cleanup is rather nice. Note how much simpler 
`Lower.FreeVarCollector` now is, as we no longer have to do heroics to 
treat enclosing instances as captured variables (or *freevars* using 
`Lower`'s lingo). As a result, `FreeVarCollector` is now effectively 
stateless - it no longer depends on the contents of `outerThisStack`. As 
such, it is now easier for clients to predict which symbols will be 
captured by a given local class, as this logic now is effectively 
independent from `Lower` (!!).

This seems to solve issues like: https://bugs.openjdk.org/browse/JDK-8334121

And, together with the patch I shared yesterday, should put a lid on the 
myriad of translation bugs associated with local classes/lambdas in 
pre-construction contexts.

Cheers
Maurizio

On 14/06/2024 13:57, Archie Cobbs wrote:
> I'm done with my hacking for now (some of which your changes subsume 
> e.g. JDK-8334252) - and I'm sure I'll want to study your improvements 
> for a while before trying anything new.
>
> Thanks!
>
> On Thu, Jun 13, 2024 at 3:34 PM Maurizio Cimadamore 
> <maurizio.cimadamore at oracle.com> wrote:
>
>     Heh. Thanks :-)
>
>     So, I think this patch can be used as a basis for further hacking
>     in Lower (e.g. to deal with inaccessible enclosing instances the
>     right way).
>
>     You seemed to have put some thought into how to do it, so if you
>     want to go ahead that's fine by me (if not, that's fine too, but
>     let's not duplicate work).
>
>     Cheers
>     Maurizio
>
>
>     On 13/06/2024 19:36, Archie Cobbs wrote:
>>     Refactoring Awesomeness Ratio (RAR) = # lines removed / # lines
>>     added.
>>
>>     Congrats on an RAR of 1.59 :)
>>
>>     -Archie
>>
>>     On Thu, Jun 13, 2024 at 12:05 PM Maurizio Cimadamore
>>     <maurizio.cimadamore at oracle.com> wrote:
>>
>>         Here's a first draft of the work to move LambdaToMethod after
>>         Lower:
>>
>>
>>     -- 
>>     Archie L. Cobbs
>
>
>
> -- 
> Archie L. Cobbs
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