Google Releases Dart 2.2

Dart is back with a new stable release 2.2, bringing faster native code and support for set literals.

Recently, Google announced the stable release of the Dart 2.2 SDK. Dart 2.2 is an incremental update to the language and it brings some significant improvements including an enhanced performance of AOT-compiled code and a new literal language feature set.
The new release offers a 16% boost to performance. And, the language now has the ability to write Set literals using curly braces { }, similar to Python and other languages. Now it is possible to create a Set as a constant.
Dart 2.2 Faster native code, support for set literals 
Source: Medium 
According to the company, it has focused specifically on the performance of AOT-compiled code. Dart 2.2 improves AOT performance by 11–16% on microbenchmarks, at the cost of a ~1% increase in code size. New optimized AOT code is now able to call the destination directly by making use of a PC-relative call.
With Dart 2.2, developers can now initialize a set and make it const using a convenient new syntax: const Set<String> currencies = {'EUR', 'USD', 'JPY'};.
The company says that the set literals feature is an example of a language construct that it was able to develop rapidly because of the CFE.
Michael Thomsen, Product Manager at Dart explained:
"The code for parsing set literals and performing type inference was implemented once in the CFE for all Dart back ends. In addition, we built a front-end-only transitional implementation that could be used by the back ends initially."
The language specification source has been moved to a new repository. Also, continuous integration has been added to ensure that a rolling draft specification is generated in PDF format as the specification for future versions of the Dart language is evolving. Both the 2.2 and rolling Dart 2.x specifications are now available.
To learn more, you can visit the official blog here.