- string/int keys use identity maps
- construct the correct type rather than relying on factory constructors when possible
- checks if key has identity semantics and use that when possible
- avoid helper calls/casts/etc in implementations
- use native ES6 Map/Set key order tracking
- optimized constructor for map literals
- fixes#30466, const maps are now canonicalized correctly
Change-Id: Id44acf3d9bf8cb153a4755aa28df08fe91bfc633
Reviewed-on: https://dart-review.googlesource.com/8167
Reviewed-by: Vijay Menon <vsm@google.com>
Jennifer Messerly
3a79c35f3c