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Destructor for @Trait is not run in certain circumstances #10802
Description
I'm not sure if this is a duplicate of an existing issue, there are many destructor related issues open already. But anyways, here it is:
#[feature(managed_boxes)];
struct DroppableStruct { a: int }
impl Drop for DroppableStruct {
fn drop(&mut self) {
println!("Dropping");
}
}
trait MyTrait { }
impl MyTrait for DroppableStruct {}
struct Whatever<'a> { w: &'a MyTrait }
impl <'a> Whatever<'a> {
fn new<'b>(w: &'b MyTrait) -> Whatever<'b> {
Whatever { w: w }
}
}
fn main() {
let mut f = DroppableStruct;
let _a = Whatever::new(@f as @MyTrait);
}This doesn't run the destructor of DroppableStruct. This is pretty much as minimal as I could get the example, many changes make it work. E.g. changing the main function body to:
let f = DroppableStruct { a: 1 };
let b = @f as @MyTrait;
let _a = Whatever::new(b);makes the destructor work. Also, not saving the Whatever struct in a variable makes it work. Also, not saving the @MyTrait in Whatever makes it work. Good luck.
Update: removed mut, was not relevant.
Update2: added a field to the struct to show it's not an issue about zero-sized structs.
Activity
emberian commentedon Dec 4, 2013
cc @nikomatsakis
flaper87 commentedon Apr 14, 2014
It's no longer possible to cast to
@-traits as of b2d30b7I tried to reproduced this bug using
~and&pointers but it worked as expected.emberian commentedon Apr 14, 2014
@flaper87 is there a testcase which covers this?
flaper87 commentedon Apr 14, 2014
@cmr I had seen it before but I can't find it anymore. Re-opening and flagging as needs test:
test: Add tests for closed issues
auto merge of #13811 : alexcrichton/rust/closed-issues, r=sfackler
Auto merge of rust-lang#10802 - flip1995:rustup, r=flip1995
Merge rust-lang#10802