sync*/async/async* generators have two parts: an entry, which does
checks and computes the element type of the result, and a body, which
is transformed after lowering to JavaScript.
The split ensures that the code for checks is done at function call
time, rather than e.g. in the moveNext method of a sync* iterator.
A following CL with optimize the split to generate one function when
there are no checks and the type argument is simple enough for textual
substitution.
Change-Id: I5414109ca851f9267871aa113a2e29b16236986d
Reviewed-on: https://dart-review.googlesource.com/54308
Commit-Queue: Stephen Adams <sra@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>