librustc: Schedule cleanups properly when coercing to a &Trait.

This commit is contained in:
Luqman Aden 2014-06-27 16:54:18 -04:00
parent abdf71cf73
commit 04e64c0c91
2 changed files with 44 additions and 2 deletions

View File

@ -277,7 +277,7 @@ fn apply_adjustments<'a>(bcx: &'a Block<'a>,
auto_ref(bcx, datum, expr)
}
fn auto_borrow_obj<'a>(bcx: &'a Block<'a>,
fn auto_borrow_obj<'a>(mut bcx: &'a Block<'a>,
expr: &ast::Expr,
source_datum: Datum<Expr>)
-> DatumBlock<'a, Expr> {
@ -285,7 +285,11 @@ fn apply_adjustments<'a>(bcx: &'a Block<'a>,
let target_obj_ty = expr_ty_adjusted(bcx, expr);
debug!("auto_borrow_obj(target={})", target_obj_ty.repr(tcx));
let mut datum = source_datum.to_expr_datum();
// Arrange cleanup, if not already done. This is needed in
// case we are auto-borrowing a Box<Trait> to &Trait
let datum = unpack_datum!(
bcx, source_datum.to_lvalue_datum(bcx, "autoborrowobj", expr.id));
let mut datum = datum.to_expr_datum();
datum.ty = target_obj_ty;
DatumBlock::new(bcx, datum)
}

View File

@ -0,0 +1,38 @@
// Copyright 2014 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.
// This would previously leak the Box<Trait> because we wouldn't
// schedule cleanups when auto borrowing trait objects.
// This program should be valgrind clean.
static mut DROP_RAN: bool = false;
struct Foo;
impl Drop for Foo {
fn drop(&mut self) {
unsafe { DROP_RAN = true; }
}
}
trait Trait {}
impl Trait for Foo {}
pub fn main() {
{
let _x: &Trait = box Foo as Box<Trait>;
}
unsafe {
assert!(DROP_RAN);
}
}