This fixes a bug that I found while trying to use the ChangeBuilder. It
also fixes a different bug that I found while testing the first. Both
resulted in the ChangeBuilder producing linked edit groups with the
wrong offset.
I found a third bug and I added a comment to identify it, but I'm not
including a fix for it. It doesn't appear to be impacting users at this
point.
While I was in the code, I removed several assertions using `isNotNull`
that can never fire because the actual value's type is non-nullable.
Change-Id: Ic76994339f5eef40316c6f0abc177275588f3996
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/498680
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Brian Wilkerson
a4290fbcb2