rust/tests/ui/borrowck/borrowck-lend-flow-if.rs
2023-01-11 09:32:08 +00:00

52 lines
1.2 KiB
Rust

// Note: the borrowck analysis is currently flow-insensitive.
// Therefore, some of these errors are marked as spurious and could be
// corrected by a simple change to the analysis. The others are
// either genuine or would require more advanced changes. The latter
// cases are noted.
fn borrow(_v: &isize) {}
fn borrow_mut(_v: &mut isize) {}
fn cond() -> bool { panic!() }
fn for_func<F>(_f: F) where F: FnOnce() -> bool { panic!() }
fn produce<T>() -> T { panic!(); }
fn inc(v: &mut Box<isize>) {
*v = Box::new(**v + 1);
}
fn pre_freeze_cond() {
// In this instance, the freeze is conditional and starts before
// the mut borrow.
let u = Box::new(0);
let mut v: Box<_> = Box::new(3);
let mut _w = &u;
if cond() {
_w = &v;
}
borrow_mut(&mut *v); //~ ERROR cannot borrow
_w.use_ref();
}
fn pre_freeze_else() {
// In this instance, the freeze and mut borrow are on separate sides
// of the if.
let u = Box::new(0);
let mut v: Box<_> = Box::new(3);
let mut _w = &u;
if cond() {
_w = &v;
} else {
borrow_mut(&mut *v);
}
_w.use_ref();
}
fn main() {}
trait Fake { fn use_mut(&mut self) { } fn use_ref(&self) { } }
impl<T> Fake for T { }