rust/tests/ui/nll/polonius/assignment-kills-loans.rs

88 lines
2.5 KiB
Rust

#![allow(dead_code)]
// This tests the various kinds of assignments there are. Polonius used to generate `killed`
// facts only on simple assignments, but not projections, incorrectly causing errors to be emitted
// for code accepted by NLL. They are all variations from example code in the NLL RFC.
//@ check-pass
//@ compile-flags: -Z polonius
struct List<T> {
value: T,
next: Option<Box<List<T>>>,
}
// Assignment to a local: the `list` assignment should clear the existing
// borrows of `list.value` and `list.next`
fn assignment_to_local<T>(mut list: &mut List<T>) -> Vec<&mut T> {
let mut result = vec![];
loop {
result.push(&mut list.value);
if let Some(n) = list.next.as_mut() {
list = n;
} else {
return result;
}
}
}
// Assignment to a deref projection: the `*list` assignment should clear the existing
// borrows of `list.value` and `list.next`
fn assignment_to_deref_projection<T>(mut list: Box<&mut List<T>>) -> Vec<&mut T> {
let mut result = vec![];
loop {
result.push(&mut list.value);
if let Some(n) = list.next.as_mut() {
*list = n;
} else {
return result;
}
}
}
// Assignment to a field projection: the `list.0` assignment should clear the existing
// borrows of `list.0.value` and `list.0.next`
fn assignment_to_field_projection<T>(mut list: (&mut List<T>,)) -> Vec<&mut T> {
let mut result = vec![];
loop {
result.push(&mut list.0.value);
if let Some(n) = list.0.next.as_mut() {
list.0 = n;
} else {
return result;
}
}
}
// Assignment to a deref field projection: the `*list.0` assignment should clear the existing
// borrows of `list.0.value` and `list.0.next`
fn assignment_to_deref_field_projection<T>(mut list: (Box<&mut List<T>>,)) -> Vec<&mut T> {
let mut result = vec![];
loop {
result.push(&mut list.0.value);
if let Some(n) = list.0.next.as_mut() {
*list.0 = n;
} else {
return result;
}
}
}
// Similar to `assignment_to_deref_field_projection` but through a longer projection chain
fn assignment_through_projection_chain<T>(
mut list: (((((Box<&mut List<T>>,),),),),),
) -> Vec<&mut T> {
let mut result = vec![];
loop {
result.push(&mut ((((list.0).0).0).0).0.value);
if let Some(n) = ((((list.0).0).0).0).0.next.as_mut() {
*((((list.0).0).0).0).0 = n;
} else {
return result;
}
}
}
fn main() {
}