Make the parser handle metadata properly according to the spec.
There has been some confusion in regards to metadata because
https://github.com/dart-lang/language/blob/master/accepted/future-releases/small-features-21Q1/feature-specification.md
(used to) say we needed a spec update.
That was done in the parser in
https://dart-review.googlesource.com/c/sdk/+/182668
but really that made the parser adhere to the spec as it was which is
also correct (as the spec change wasn't needed at all).
The parser also needs to be able to skip metadata, though, and that
wasn't done it that CL which caused the issues in
https://github.com/dart-lang/sdk/issues/45120
The work directly in this CL is:
* Add lots of comments to parseMetadata to make them more up-to-date with
the spec.
* Fix skipMetadata to correspond to parseMetadata.
* Tests verifying that 45120 is fixed in the parser and that metadata in
general works as expected in the parser.
(In working on this, the future specification was corrected to say that the
spec did not need updating. Thanks to Erik for the quick turn-around
there).
Bug: #45120
Change-Id: Id1e4912cac7e5d9113efe083b3ecd06e6834a16e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/190880
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Jens Johansen