Idea how to implement VT/VO compatibility in JVM

Stéphane Épardaud stef at
Thu Jan 22 15:03:17 UTC 2015

On 01/22/2015 03:46 PM, Stéphane Épardaud wrote:
> On 01/22/2015 03:42 PM, Vitaly Davidovich wrote:
>> Ok can we first agree that List <T> is NOT List <Object>? :) That's 
>> unsound since you can't add any Object in there if things are 
>> reified.  I think you guys mean List <?>.
> Well, that what I meant by "variance issues aside". It is unsound but 
> detected at runtime. This is already a limitation of List in Java at 
> compile-time, I'm not proposing to fix it.
And yeah, goes to show how I got used to List<T extends Object> being a 
subtype of List<Object> in Ceylon where List is immutable and covariant 
in T ;)

More information about the valhalla-dev mailing list