If you mean type annotations then no, right now Dart VM does not use type annotations to optimize things. Dart VM features an classical adaptive optimizations

If you mean type annotations then no, right now Dart VM does not use type annotations to optimize things. Dart VM features an classical adaptive optimizations pipeline that first gathers type information from the run and then optimizes hot methods using collected type feedback to specialize the code. For more implementation details about Dart VM optimizing compiler you can check out my talk from Strange Loop 2013 http://s3.mrale.ph/StrangeLoop2013.pdf http://s3.mrale.ph/StrangeLoop2013.pdf