File: borrowck-mut-borrow-of-mut-base-ptr.rs

package info (click to toggle)
rustc 1.89.0%2Bdfsg1-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 906,624 kB
  • sloc: xml: 158,148; python: 34,888; javascript: 19,595; sh: 19,221; ansic: 13,046; cpp: 7,144; asm: 4,376; makefile: 692; lisp: 174; sql: 15
file content (28 lines) | stat: -rw-r--r-- 777 bytes parent folder | download | duplicates (25)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
// Test that attempt to mutably borrow `&mut` pointer while pointee is
// borrowed yields an error.
//
// Example from compiler/rustc_borrowck/borrowck/README.md



fn foo<'a>(mut t0: &'a mut isize,
           mut t1: &'a mut isize) {
    let p: &isize = &*t0;     // Freezes `*t0`
    let mut t2 = &mut t0;   //~ ERROR cannot borrow `t0`
    **t2 += 1;              // Mutates `*t0`
    p.use_ref();
}

fn bar<'a>(mut t0: &'a mut isize,
           mut t1: &'a mut isize) {
    let p: &mut isize = &mut *t0; // Claims `*t0`
    let mut t2 = &mut t0;       //~ ERROR cannot borrow `t0`
    **t2 += 1;                  // Mutates `*t0` but not through `*p`
    p.use_mut();
}

fn main() {
}

trait Fake { fn use_mut(&mut self) { } fn use_ref(&self) { }  }
impl<T> Fake for T { }