synchronized - shared but actually useful

[FeepingCreature]

On Wednesday, 31 October 2018 at 10:36:35 UTC, FeepingCreature 
wrote:
> On Wednesday, 31 October 2018 at 10:25:52 UTC, Jonathan M Davis 
> wrote:
>> synchronized classes really only protect the stuff that sit 
>> directly inside the class itself, not what the class' member 
>> variables refer to. If they were to fully protect everything 
>> inside of it, then you couldn't really pass anything in or out 
>> of it.
>>
>> - Jonathan M Davis
>
> You could pass other synchronized objects, immutable data and 
> data by value.
>
> In many project designs, that's really all you need.

Apropos of running into a production threading error that would 
have been fixed by this synchronized proposal, let me just bump 
this thread to note that it's four years later and this code 
still fails to compile for absolutely zero reason:

```
synchronized class A
{
     private int e;
     void foo() { e++; }
}
```