3 ms·

Due to lifetime elision you can mostly skip lifetimes if you leave a bit of performance on the table.

• bluehex 10mo ago
  How does lifetime elision affect performance? I thought the compiler just inferred lifetimes that you would have had to manually annotate. Naively, it seems to me that the performance should be identical.
  • steveklabnik 10mo ago
    Strictly speaking, elision just adds lifetimes based on common patterns, so yes, it wouldn't directly affect performance. I believe your parent is implying that if you skip using a lifetime and do something else instead to make it easier, that may be less performant.
    • adastra22 10mo ago
      I think his point is the lifetime you’d put there is identical to the lifetime that is inferred/elided. So there is literally no difference.
      • steveklabnik 10mo ago
        I thought they meant the case where you go "ugh, I don't want to write a lifetime here" and then change your code, because you have to. If you don't have to, then yes, there's literally no difference.
    • ViewTrick1002 10mo ago
      Exactly. Cloning values, collecting iterators into Vecs and then continue the transformation rather than keeping it lazy all the way through. Skipping structs/enums with references.