rust/src/test/compile-fail/borrowck-lend-flow-loop.rs

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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// 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: &int) {}
fn borrow_mut(_v: &mut int) {}
fn cond() -> bool { fail!() }
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fn for_func(_f: &fn() -> bool) -> bool { fail!() }
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fn produce<T>() -> T { fail!(); }
fn inc(v: &mut ~int) {
*v = ~(**v + 1);
}
fn loop_overarching_alias_mut() {
// In this instance, the borrow encompasses the entire loop.
let mut v = ~3;
let mut x = &mut v;
**x += 1;
loop {
borrow(v); //~ ERROR cannot borrow
}
}
fn block_overarching_alias_mut() {
// In this instance, the borrow encompasses the entire closure call.
let mut v = ~3;
let mut x = &mut v;
for 3.times {
borrow(v); //~ ERROR cannot borrow
}
*x = ~5;
}
fn loop_aliased_mut() {
// In this instance, the borrow is carried through the loop.
let mut v = ~3;
let mut w = ~4;
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let mut _x = &w;
loop {
borrow_mut(v); //~ ERROR cannot borrow
_x = &v;
}
}
fn while_aliased_mut() {
// In this instance, the borrow is carried through the loop.
let mut v = ~3;
let mut w = ~4;
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let mut _x = &w;
while cond() {
borrow_mut(v); //~ ERROR cannot borrow
_x = &v;
}
}
fn for_loop_aliased_mut() {
// In this instance, the borrow is carried through the loop.
let mut v = ~3;
let mut w = ~4;
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let mut _x = &w;
for for_func {
borrow_mut(v); //~ ERROR cannot borrow
_x = &v;
}
}
fn loop_aliased_mut_break() {
// In this instance, the borrow is carried through the loop.
let mut v = ~3;
let mut w = ~4;
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let mut _x = &w;
loop {
borrow_mut(v);
_x = &v;
break;
}
borrow_mut(v); //~ ERROR cannot borrow
}
fn while_aliased_mut_break() {
// In this instance, the borrow is carried through the loop.
let mut v = ~3;
let mut w = ~4;
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let mut _x = &w;
while cond() {
borrow_mut(v);
_x = &v;
break;
}
borrow_mut(v); //~ ERROR cannot borrow
}
fn for_aliased_mut_break() {
// In this instance, the borrow is carried through the loop.
let mut v = ~3;
let mut w = ~4;
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let mut _x = &w;
for for_func {
// here we cannot be sure that `for_func` respects the break below
borrow_mut(v); //~ ERROR cannot borrow
_x = &v;
break;
}
borrow_mut(v); //~ ERROR cannot borrow
}
fn while_aliased_mut_cond(cond: bool, cond2: bool) {
let mut v = ~3;
let mut w = ~4;
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let mut x = &mut w;
while cond {
**x += 1;
borrow(v); //~ ERROR cannot borrow
if cond2 {
x = &mut v; //~ ERROR cannot borrow
}
}
}
fn loop_break_pops_scopes<'r>(_v: &'r mut [uint], f: &fn(&'r mut uint) -> bool) {
// Here we check that when you break out of an inner loop, the
// borrows that go out of scope as you exit the inner loop are
// removed from the bitset.
while cond() {
while cond() {
// this borrow is limited to the scope of `r`...
let r: &'r mut uint = produce();
if !f(&mut *r) {
break; // ...so it is not live as exit the `while` loop here
}
}
}
}
fn loop_loop_pops_scopes<'r>(_v: &'r mut [uint], f: &fn(&'r mut uint) -> bool) {
// Similar to `loop_break_pops_scopes` but for the `loop` keyword
while cond() {
while cond() {
// this borrow is limited to the scope of `r`...
let r: &'r mut uint = produce();
if !f(&mut *r) {
loop; // ...so it is not live as exit (and re-enter) the `while` loop here
}
}
}
}
fn main() {}