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by-val and by-move can be dangerous when combined #2443
Description
Currently, the compiler does not account for the fact that "by value" passing of ref-counted boxes is in fact a borrow. This can be fixed easily enough in borrowck (or, I imagine, in alias). In any case, I added an xfail'd test (by-val-and-by-move.rs) that demonstrates the problem. This test fails (note the environment variable RUST_POISON_ON_FREE---without that, the test may accidentally pass even though it is accessing a freed pointer).
// xfail-test
// exec-env:RUST_POISON_ON_FREE
fn it_takes_two(x: @int, -y: @int) -> int {
free(y);
#debug["about to deref"];
*x
}
fn free<T>(-t: T) {
}
fn main() {
let z = @3;
assert 3 == it_takes_two(z, z);
}
Activity
nikomatsakis commentedon Jun 8, 2012
just realized---this should be easy to fix with borrowck, but we don't handle it now. we don't seem to get the scope right when checking that there is no move from a borrow ptr.
graydon commentedon Aug 31, 2012
Obsolete given scheduled removal of modes (or at least WONTFIX).
removed test referring to WONTFIX bug rust-lang#2443
removed test referring to WONTFIX bug rust-lang#2443
removed test referring to WONTFIX bug rust-lang#2443
Auto merge of rust-lang#2890 - oli-obk:ui_test, r=RalfJung
Auto merge of rust-lang#2901 - oli-obk:noisy, r=RalfJung
Bump Kani dependencies (rust-lang#2443)
Merge pull request rust-lang#2443 from smanilov/patch-21
Merge rust-lang#2466