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DDC passes, dart2js and VM fail. ---- The dart2js and VM fringe-following scheme could be modified to call `.iterator` at the `yield*` site and use the Iterator instead of the Iterable. Calling `.iterator` at the `yield*` site would move the exception to the right place. It might also present an optimization opportunity where the call might be inlined, or the entry into the fringe-following algorithm could be made more efficient based on the type of the iterator. Change-Id: Icfb6f7ca0b92cbeea1349ce138e469cfa707f571 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/295200 Commit-Queue: Stephen Adams <sra@google.com> Reviewed-by: Lasse Nielsen <lrn@google.com>