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

37 lines
928 B
Rust

// Suggest not mutably borrowing a mutable reference
#![crate_type = "rlib"]
pub fn f(b: &mut i32) {
//~^ ERROR cannot borrow
//~| NOTE not mutable
//~| NOTE the binding is already a mutable borrow
h(&mut b);
//~^ NOTE cannot borrow as mutable
//~| HELP try removing `&mut` here
g(&mut &mut b);
//~^ NOTE cannot borrow as mutable
//~| HELP try removing `&mut` here
}
pub fn g(b: &mut i32) { //~ NOTE the binding is already a mutable borrow
h(&mut &mut b);
//~^ ERROR cannot borrow
//~| NOTE cannot borrow as mutable
//~| HELP try removing `&mut` here
}
pub fn h(_: &mut i32) {}
trait Foo {
fn bar(&mut self);
}
impl Foo for &mut String {
fn bar(&mut self) {}
}
pub fn baz(f: &mut String) { //~ HELP consider making the binding mutable
f.bar(); //~ ERROR cannot borrow `f` as mutable, as it is not declared as mutable
//~^ NOTE cannot borrow as mutable
}