X-Git-Url: https://git.ralfj.de/rust-101.git/blobdiff_plain/63b7a79069a399c32d575bb71832fcad134117c9..a52087dc8f244861d144229b04e64f934ed1d03f:/src/part06.rs?ds=sidebyside diff --git a/src/part06.rs b/src/part06.rs index 8f9a723..9552eb5 100644 --- a/src/part06.rs +++ b/src/part06.rs @@ -138,8 +138,8 @@ fn rust_foo(mut v: Vec) -> i32 { //@ When analyzing the code of `rust_foo`, Rust has to assign a lifetime to `first`. It will choose the scope //@ where `first` is valid, which is the entire rest of the function. Because `head` ties the lifetime of its //@ argument and return value together, this means that `&v` also has to borrow `v` for the entire duration of -//@ the function `rust_foo`. So when we try to borrow `v` exclusively for `push`, Rust complains that the two references (the one -//@ for `head`, and the one for `push`) overlap. Lucky us! Rust caught our mistake and made sure we don't crash the program. +//@ the function `rust_foo`. So when we try to create a unique reference to `v` for `push`, Rust complains that the two references (the one +//@ for `head`, and the one for `push`) overlap, so neither of them can be unique. Lucky us! Rust caught our mistake and made sure we don't crash the program. //@ //@ So, to sum this up: Lifetimes enable Rust to reason about *how long* a reference is valid, how long ownership has been borrowed. We can thus //@ safely write functions like `head`, that return references into data they got as argument, and make sure they