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

[Maurizio Cimadamore]

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
>