mirror of https://github.com/rust-lang/rust
62 lines
1.9 KiB
Rust
62 lines
1.9 KiB
Rust
//@ revisions: nll_target
|
|
|
|
// The following revisions are disabled due to missing support from two-phase beyond autorefs
|
|
//@ unused-revision-names: nll_beyond
|
|
//@[nll_beyond] compile-flags: -Z two-phase-beyond-autoref
|
|
|
|
// This is an important corner case pointed out by Niko: one is
|
|
// allowed to initiate a shared borrow during a reservation, but it
|
|
// *must end* before the activation occurs.
|
|
//
|
|
// FIXME: for clarity, diagnostics for these cases might be better off
|
|
// if they specifically said "cannot activate mutable borrow of `x`"
|
|
//
|
|
// The convention for the listed revisions: "lxl" means lexical
|
|
// lifetimes (which can be easier to reason about). "nll" means
|
|
// non-lexical lifetimes. "nll_target" means the initial conservative
|
|
// two-phase borrows that only applies to autoref-introduced borrows.
|
|
// "nll_beyond" means the generalization of two-phase borrows to all
|
|
// `&mut`-borrows (doing so makes it easier to write code for specific
|
|
// corner cases).
|
|
|
|
#![allow(dead_code)]
|
|
|
|
fn read(_: &i32) { }
|
|
|
|
fn ok() {
|
|
let mut x = 3;
|
|
let y = &mut x;
|
|
{ let z = &x; read(z); }
|
|
//[nll_target]~^ ERROR cannot borrow `x` as immutable because it is also borrowed as mutable
|
|
*y += 1;
|
|
}
|
|
|
|
fn not_ok() {
|
|
let mut x = 3;
|
|
let y = &mut x;
|
|
let z = &x;
|
|
//[nll_target]~^ ERROR cannot borrow `x` as immutable because it is also borrowed as mutable
|
|
*y += 1;
|
|
//[nll_beyond]~^ ERROR cannot borrow `x` as mutable because it is also borrowed as immutable
|
|
read(z);
|
|
}
|
|
|
|
fn should_be_ok_with_nll() {
|
|
let mut x = 3;
|
|
let y = &mut x;
|
|
let z = &x;
|
|
//[nll_target]~^ ERROR cannot borrow `x` as immutable because it is also borrowed as mutable
|
|
read(z);
|
|
*y += 1;
|
|
}
|
|
|
|
fn should_also_eventually_be_ok_with_nll() {
|
|
let mut x = 3;
|
|
let y = &mut x;
|
|
let _z = &x;
|
|
//[nll_target]~^ ERROR cannot borrow `x` as immutable because it is also borrowed as mutable
|
|
*y += 1;
|
|
}
|
|
|
|
fn main() { }
|