Different behavior between (F) and (Object & F)

[bitter_fox]

F#clone was provided default implementation.
My case is:

interface F
{
    default Object clone() {}

    void m();
}

F f = () -> {};

And it now passes compiler and it makes:

class $$lambda$n implements F
{
    public void m()
    {
        Enclosing.lambdan();
    }

    // override protected Object clone()
}

I think () -> {} shouldn't pass compiler

Regards,
bitter_fox

2012/11/9 Maurizio Cimadamore <maurizio.cimadamore at oracle.com>

> Forget my previous email - I know realize what your email is about -
> should this code work?
>
> interface F {
>     Object clone();
> }
>
> F f = ()->null;
>
> I think it should - the metafactory will ggenerate a _public_
> implementation for the clone method - i.e.
>
> class $$$lambdaClass$$$ implements F {
>     public Object clone() {
>         return null;
>     }
> }
>
> Which is legal...
>
> Maurizio
>
> On 08/11/12 14:49, Maurizio Cimadamore wrote:
>
>> On 08/11/12 14:40, bitter_fox wrote:
>>
>>> In this case, the overridden method is F#clone and this is public, and
>>> the overriding method is Object#clone and this is not public. This
>>> would be compile-time error.
>>>
>> Strictly speaking this is all true. Javac (and other compilers too) has
>> a tendency to defer this kind of checks. For instance, even w/o lambdas,
>> it is possible to write code like:
>>
>> class Foo<X extends Object & F> { }
>>
>> Now, should this be illegal? The current view is that we let the
>> type-witness to provide a public overrider for Object's clone.
>>
>> So the well-formedness check for intersection types has been
>> historically loose in this respect; right now, javac is re-using the
>> same well-formedness check regardless of whether the intersection type
>> appears as a type-variable bound or as a cast target; this seems
>> reasonable, however it leaves out few cases as you correctly point out.
>> It is very likely that some additional restrictions on intersection
>> types will come out when they are used as a target of a functional
>> expression.
>>
>> Maurizio
>>
>>
>