Mark all currently unimplementable types as `final`, or `sealed` for `num` and `final` for `Function`.
Mark all current classes intended as mixins as `mixin class`.
More additions and cleanup will follow,
but this change should make everything keep working as today
if we flip the switch.
TEST= No new tests, very little actual change, covered by existing tests with few changes. Will add more tests when adding more modifiers.
Change-Id: I40e724f823e7f88cdef186d2f73874df256e2f43
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/281683
Reviewed-by: Siva Annamalai <asiva@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Lasse Nielsen <lrn@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Kallen Tu <kallentu@google.com>
Lasse R.H. Nielsen
0c05e33836