Added tests illustrating when and when not to use the UGEH attribute w.r.t. a trait bound.
This commit is contained in:
parent
92da3f9464
commit
e2e261f376
2 changed files with 101 additions and 0 deletions
50
src/test/compile-fail/issue28498-reject-trait-bound.rs
Normal file
50
src/test/compile-fail/issue28498-reject-trait-bound.rs
Normal file
|
@ -0,0 +1,50 @@
|
|||
// Copyright 2015 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.
|
||||
|
||||
// Demonstrate that having a trait bound causes dropck to reject code
|
||||
// that might indirectly access previously dropped value.
|
||||
//
|
||||
// Compare with run-pass/issue28498-ugeh-with-trait-bound.rs
|
||||
|
||||
use std::fmt;
|
||||
|
||||
#[derive(Debug)]
|
||||
struct ScribbleOnDrop(String);
|
||||
|
||||
impl Drop for ScribbleOnDrop {
|
||||
fn drop(&mut self) {
|
||||
self.0 = format!("DROPPED");
|
||||
}
|
||||
}
|
||||
|
||||
struct Foo<T:fmt::Debug>(u32, T);
|
||||
|
||||
impl<T:fmt::Debug> Drop for Foo<T> {
|
||||
fn drop(&mut self) {
|
||||
// Use of `unsafe_destructor_blind_to_params` is unsound,
|
||||
// because we access `T` fmt method when we pass `self.1`
|
||||
// below, and thus potentially read from borrowed data.
|
||||
println!("Dropping Foo({}, {:?})", self.0, self.1);
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {
|
||||
let (last_dropped, foo0);
|
||||
let (foo1, first_dropped);
|
||||
|
||||
last_dropped = ScribbleOnDrop(format!("last"));
|
||||
first_dropped = ScribbleOnDrop(format!("first"));
|
||||
foo0 = Foo(0, &last_dropped);
|
||||
//~^ ERROR `last_dropped` does not live long enough
|
||||
foo1 = Foo(1, &first_dropped);
|
||||
//~^ ERROR `first_dropped` does not live long enough
|
||||
|
||||
println!("foo0.1: {:?} foo1.1: {:?}", foo0.1, foo1.1);
|
||||
}
|
51
src/test/run-pass/issue28498-ugeh-with-trait-bound.rs
Normal file
51
src/test/run-pass/issue28498-ugeh-with-trait-bound.rs
Normal file
|
@ -0,0 +1,51 @@
|
|||
// Copyright 2015 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.
|
||||
|
||||
// Demonstrate the use of the unguarded escape hatch with a trait bound
|
||||
// to assert that destructor will not access any dead data.
|
||||
//
|
||||
// Compare with compile-fail/issue28498-reject-trait-bound.rs
|
||||
|
||||
#![feature(dropck_parametricity)]
|
||||
|
||||
use std::fmt;
|
||||
|
||||
#[derive(Debug)]
|
||||
struct ScribbleOnDrop(String);
|
||||
|
||||
impl Drop for ScribbleOnDrop {
|
||||
fn drop(&mut self) {
|
||||
self.0 = format!("DROPPED");
|
||||
}
|
||||
}
|
||||
|
||||
struct Foo<T:fmt::Debug>(u32, T);
|
||||
|
||||
impl<T:fmt::Debug> Drop for Foo<T> {
|
||||
#[unsafe_destructor_blind_to_params]
|
||||
fn drop(&mut self) {
|
||||
// Use of `unsafe_destructor_blind_to_params` is sound,
|
||||
// because destructor never accesses the `Debug::fmt` method
|
||||
// of `T`, despite having it available.
|
||||
println!("Dropping Foo({}, _)", self.0);
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {
|
||||
let (last_dropped, foo0);
|
||||
let (foo1, first_dropped);
|
||||
|
||||
last_dropped = ScribbleOnDrop(format!("last"));
|
||||
first_dropped = ScribbleOnDrop(format!("first"));
|
||||
foo0 = Foo(0, &last_dropped);
|
||||
foo1 = Foo(1, &first_dropped);
|
||||
|
||||
println!("foo0.1: {:?} foo1.1: {:?}", foo0.1, foo1.1);
|
||||
}
|
Loading…
Reference in a new issue