In Zend 5.3 they decided that closures should inherit the ##$this## from the containing scope. This brings us close to paraity with them. The remaining thing is to make
function() use ($this) {}
fatal after we purge it from WWW.
Instead of having the body of the closure be in the ##__invoke()## on the ##Closure## class, instead we make an anonymous function on the real class and put the body there. The signature for this function is:
function methodForClosure$1234($arg1, $arg2, ..., $use1, $use2, ...)
and then ##__invoke## now just takes all the params that were passed to it, puts them as the first args to the anonymous function, then takes all the use variables it had saved up and passed them in as the next params.
I tried to not have an ##__invoke## at all, but I ended up basically doing the same parameter and use var repacking in iopFCall (and would have had to do it in x86 code too). I opted for doing the rejiggering in bytecode. If I did it in raw PHP I think it would have been much slower with many ##func_get_args()## and array operations.
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
ptarjan