Just a basic programmer living in California

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Joined 7 months ago
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Cake day: February 23rd, 2024

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  • To expand on why generics are preferred, just in case you haven’t seen these points yet: the performance downsides of Box<dyn MyTrait> are,

    • methods use dynamic dispatch in this case
    • requires heap allocation

    There is also a possible type theory objection which is that normally there is a distinction between types and traits. Traits are not types themselves, but instead define sets of types with shared behavior. (That’s why the same feature in Haskell is called a “type class”, because it defines a class of types that have something in common.) But dyn turns a trait into a type which undermines the type/trait distinction. It’s useful enough to justify being in the language, but a little unsettling from a certain perspective.