On Jan 8, 2019, at 3:14 PM, Brian Goetz <brian.go...@oracle.com> wrote:
>
> Essentially, you're saying that if someone declares a pattern variable that
> would shadow a DU (final, please!) local, then the variables are merged and
> the scope is pinned at the scope of the local. That's nice in that the scope
> and declaration point are now clearer, but on the other hand the concept of
> binding is now muddier: pattern variables now interact with shadowing, with
> locals, and maybe get sucked into mutability too ("why not just treat binding
> as ordinary local assignment".) So it plugs one leak, but opens up several
> others.
True enough. But it seems that a lot of that machinery is already
a sunk cost, for merging bindings in (a instanceof T t || b instanceof T t).
The new thing would be putting blank (yes, implicitly final!) declarations
into the mix as candidates for merging. That strikes me as a plausible
bargain.
