rust/tests/ui/borrowck/borrowck-mut-borrow-of-mut-base-ptr.rs
2023-01-11 09:32:08 +00:00

29 lines
777 B
Rust

// 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 { }