list literal gotcha and suggestion

[Rémi Forax]

Reinier Zwitserloot a écrit :
> You yourself said this internal type can't ever be seen in java code.  
> Collection is an interface, so what's it going to _be_? A set? A list?  
>   

The compiler can also reject that code because it's ambiguous.

> A new unspecified implementation of collection that is neither? What  
> if I pass {1, 2, 3, 1} - will the duplicate be removed? What would it  
> toString() to? (HashSet and ArrayList have different toString()  
> implementations).
>
>   --Reinier Zwitserloot
>   
Rémi

>
>
> On 2009/07/10, at 07:20, Neal Gafter wrote:
>
>   
>> If it is "an initializer" that is "compatible" with the "Collection"  
>> argument type, then the "conversion" exists and the method is a  
>> candidate.  If the method is selected as the most specific one  
>> during overload resolution, then the generated code will "perform  
>> the conversion", which essentially means constructing the collection  
>> object.
>>
>> On Tue, Oct 6, 2009 at 7:45 PM, Reinier Zwitserloot <reinier at zwitserloot.com 
>>     
>>> wrote:
>>>       
>> So, passing a {1, 2, 3} literal inline to a method that takes a  
>> Collection will not require a cast?
>>
>> Please explain how that would work.
>>
>>  --Reinier Zwitserloot
>>
>>
>>
>> On 2009/06/10, at 23:52, Neal Gafter wrote:
>>
>>     
>>> On Tue, Oct 6, 2009 at 1:48 PM, Reinier Zwitserloot <reinier at zwitserloot.com 
>>>       
>>>> wrote:
>>>>         
>>> On 2009/06/10, at 21:32, Neal Gafter wrote:
>>> Not at all.  I believe that the cast would be unnecessary in  
>>> virtually all use contexts, just as the cast from "3" to "byte" is  
>>> unnnecessary in virtually all use contexts.
>>>
>>> Doesn't coin include byte literals?
>>>
>>> Yes.  That has nothing to do with the part of the existing language  
>>> specification that allows "3" to be assigned to a "byte".
>>>
>>> I think you overstate. "Virtually all use contexts"? I'd say that  
>>> methods taking in a java.util.Collection is a pretty big use context.
>>>
>>> Agreed, those contexts are included.
>>>
>>> -Neal
>>>       
>>     
>
>
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