7e9c1c8018
This changes the parser to always interpret `extension type` as the start of an extension type declaration. Recovery is added to handle missing identifier, primary constructor, parameter constructor parameters, and extension type declaration body. Change-Id: I98cac0b2641167c4708fa20b22f0de0a70336457 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/321704 Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Reviewed-by: Jens Johansen <jensj@google.com> Commit-Queue: Johnni Winther <johnniwinther@google.com>