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There's no technical reason the Rust borrow checker couldn't run without annotations either- that's a design choice, similar to the way Rust requires function t
by Rusky 7y ago
There's no technical reason the Rust borrow checker couldn't run without annotations either- that's a design choice, similar to the way Rust requires function types even though it could infer them. It makes inter-function contracts clearer, which improves error messages, and avoid the need for whole-program analysis.
I couldn't find anything more about "view propagation" either but I strongly suspect it's no more powerful. Probably less and/or buggier at this point, given its relative maturity.
- giornogiovanna 7y agoBut how would you distinguish between struct A<'a, 'b>(&'a u8, &'b u8); and struct B<'a>(&'a u8, &'a u8); without lifetime annotations?
- sanxiyn 7y agoYou can always assume the former(all lifetimes are different). It is strictly more general.
- giornogiovanna 7y agoThanks, so lifetimes can definitely be inferred for safe code (although just like type inference, they can lead to leaky abstractions). But aren't lifetime annotations necessary for unsafe code? How could you cast a pointer into a struct into a raw pointer and back, while preserving the lifetime, without them?
- nudq 7y agoWe'd start by making sure these lifetimes need distinguishing, i.e. that they aren't actually equivalent.