mirror of https://github.com/rust-lang/rust
133 lines
3.1 KiB
Rust
133 lines
3.1 KiB
Rust
fn borrow(_v: &isize) {}
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fn borrow_mut(_v: &mut isize) {}
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fn cond() -> bool { panic!() }
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fn produce<T>() -> T { panic!(); }
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fn inc(v: &mut Box<isize>) {
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*v = Box::new(**v + 1);
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}
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fn loop_overarching_alias_mut() {
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// In this instance, the borrow ends on the line before the loop
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let mut v: Box<_> = Box::new(3);
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let mut x = &mut v;
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**x += 1;
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loop {
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borrow(&*v); // OK
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}
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}
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fn block_overarching_alias_mut() {
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// In this instance, the borrow encompasses the entire closure call.
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let mut v: Box<_> = Box::new(3);
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let mut x = &mut v;
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for _ in 0..3 {
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borrow(&*v); //~ ERROR cannot borrow
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}
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*x = Box::new(5);
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}
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fn loop_aliased_mut() {
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// In this instance, the borrow ends right after each assignment to _x
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let mut v: Box<_> = Box::new(3);
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let mut w: Box<_> = Box::new(4);
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let mut _x = &w;
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loop {
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borrow_mut(&mut *v); // OK
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_x = &v;
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}
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}
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fn while_aliased_mut() {
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// In this instance, the borrow ends right after each assignment to _x
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let mut v: Box<_> = Box::new(3);
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let mut w: Box<_> = Box::new(4);
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let mut _x = &w;
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while cond() {
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borrow_mut(&mut *v); // OK
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_x = &v;
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}
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}
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fn loop_aliased_mut_break() {
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// In this instance, the borrow ends right after each assignment to _x
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let mut v: Box<_> = Box::new(3);
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let mut w: Box<_> = Box::new(4);
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let mut _x = &w;
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loop {
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borrow_mut(&mut *v);
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_x = &v;
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break;
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}
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borrow_mut(&mut *v); // OK
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}
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fn while_aliased_mut_break() {
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// In this instance, the borrow ends right after each assignment to _x
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let mut v: Box<_> = Box::new(3);
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let mut w: Box<_> = Box::new(4);
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let mut _x = &w;
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while cond() {
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borrow_mut(&mut *v);
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_x = &v;
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break;
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}
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borrow_mut(&mut *v); // OK
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}
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fn while_aliased_mut_cond(cond: bool, cond2: bool) {
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let mut v: Box<_> = Box::new(3);
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let mut w: Box<_> = Box::new(4);
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let mut x = &mut w;
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while cond {
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**x += 1;
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borrow(&*v); //~ ERROR cannot borrow
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if cond2 {
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x = &mut v; // OK
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}
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}
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}
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fn loop_break_pops_scopes<'r, F>(_v: &'r mut [usize], mut f: F) where
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F: FnMut(&'r mut usize) -> bool,
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{
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// Here we check that when you break out of an inner loop, the
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// borrows that go out of scope as you exit the inner loop are
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// removed from the bitset.
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while cond() {
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while cond() {
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// this borrow is limited to the scope of `r`...
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let r: &'r mut usize = produce();
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if !f(&mut *r) {
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break; // ...so it is not live as exit the `while` loop here
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}
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}
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}
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}
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fn loop_loop_pops_scopes<'r, F>(_v: &'r mut [usize], mut f: F)
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where F: FnMut(&'r mut usize) -> bool
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{
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// Similar to `loop_break_pops_scopes` but for the `loop` keyword
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while cond() {
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while cond() {
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// this borrow is limited to the scope of `r`...
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let r: &'r mut usize = produce();
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if !f(&mut *r) {
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continue; // ...so it is not live as exit (and re-enter) the `while` loop here
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}
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}
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}
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}
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fn main() {}
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