alt Hacker NewsThe Default trait provides a function that actually constructs the type in question. But here the ! type can never be constructed, so the only way to implement Default would be to have it panic, loop infinitely, or otherwise fail at runtime.
So this would risk turning a compile-time error into a runtime error.
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xg15 • yesterday at 8:53 PM
Ah, that makes sense. Rust noob here, so I wasn't aware traits can act on types directly without any instance of the type. Thanks for the info!
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Moreover, Rust traits' associated constants/types get in the way of having a proper bottom type. What would <! as Iterator>::Item be? (In Scala I think it just doesn't compile?)