End of the storage hints model ?

[Brian Goetz]

Yes, and this is true not only for functional interfaces, but for ArrayList<T> as well; we don’t know if the user really meant List<int> or List<Integer>.  So the implementation will guess wrong some of the time.  

> On Jul 22, 2022, at 12:16 PM, Remi Forax <forax at univ-mlv.fr> wrote:
> 
> I've found where the storage hints model does not work well.
> 
> The storage hints model as its own name says works on implementations, but it does not work on functional interface types.
> 
> By example, we have functional interfaces in java.util.function where the same interface say j.u.f.Function is used sometime with the return/parameter values being nullable sometimes it is used with the return/parameter values that we hope to be non-nullable. For example, the function in stream.map(function) wants to be non-nullable but the function in map.compute(function) allows nullable values.
> 
> Thus when declaring j.u.f.Function we can not decide if the parameter type / return type should be annotated by the .flat storage hint or not.
> Which means that the storage hints model will not provide enough information for the VM to compute the precise calling convention. 
> 
> So the storage hints model is not dead dead but a model based on the type propagation is more efficient.
> 
> Rémi