Not really. Counter-intuitively, all annotated types are thrown out at runtime, as far as I recall. The VM learns about types in the same way that JS VMs do. Dart&#x27;s performance wins over JS are elsewhere (object construction and access (designed without prototypes to avoid the performance pitfalls of V8&#x27;s hidden classes), lack of global object, with and eval…).<p>&gt; <i>The VM designers say that in practice, type guarantees really don’t help them nearly as much as you might think, because type checks are not a major drain on performance.</i><p><a href="https:&#x2F;&#x2F;www.dartlang.org&#x2F;articles&#x2F;why-dart-types&#x2F;#why-do-type-annotations-have-no-effect-at-runtime" rel="nofollow">https:&#x2F;&#x2F;www.dartlang.org&#x2F;articles&#x2F;why-dart-types&#x2F;#why-do-typ...</a>