RFR 7118066: Warnings in java.util.concurrent package

[Rémi Forax]

On 12/06/2011 08:07 AM, David Holmes wrote:
> On 6/12/2011 12:14 PM, David Holmes wrote:
>> On 6/12/2011 11:45 AM, Rémi Forax wrote:
>>> On 12/06/2011 02:12 AM, David Holmes wrote:
>>>> Is the reason for constructs like this:
>>>>
>>>> HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry<?,?>[cap];
>>>>
>>>> that we can't utilize diamond? Otherwise it would nicely reduce to:
>>>>
>>>> HashEntry<K,V>[] tab = new HashEntry<>[cap];
>>>
>>> This should not compile because otherwise you can write
>>
>> This compiles fine:
>>
>> @SuppressWarnings("unchecked")
>> public class TestGenerics<K,V> {
>>
>> static class HashEntry<K,V> { }
>>
>> public void m() {
>> HashEntry<K,V>[] newTable = new HashEntry<>[1];
>> }
>> }
>>
>>
>> I don't know exactly what the type inference code does but I assumed it
>> effectively converted the above to:
>>
>> HashEntry<K,V>[] newTable = (HashEntry<K,V>[]) new HashEntry[1];
>>
>> and not to:
>>
>> HashEntry<K,V>[] newTable = new HashEntry<K,V>[1];
>>
>> which of course does not compile.
>
> Hmmm. Perhaps this is a compilation accident? I don't see anything in 
> the spec that allows diamond to be used with array creation expressions.

Yes, it's a bug of javac, eclipse compiler rejects this code.

>
> David
> -----

Rémi