Replace unsafe_destructor_blind_to_params with may_dangle

This commit is contained in:
Lzu Tao 2019-07-10 18:49:05 +00:00
parent 4bb6b4a5ed
commit ab3adf380d
8 changed files with 21 additions and 31 deletions

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@ -1,12 +1,11 @@
// run-pass
#![allow(deprecated)]
// Check that item-less traits do not cause dropck to inject extra
// region constraints.
#![allow(non_camel_case_types)]
#![feature(dropck_parametricity)]
#![feature(dropck_eyepatch)]
trait UserDefined { }
@ -20,9 +19,8 @@ impl<'a, T> UserDefined for &'a T { }
// ```
macro_rules! impl_drop {
($Bound:ident, $Id:ident) => {
struct $Id<T:$Bound>(T);
impl <T:$Bound> Drop for $Id<T> {
#[unsafe_destructor_blind_to_params]
struct $Id<T: $Bound>(T);
unsafe impl <#[may_dangle] T: $Bound> Drop for $Id<T> {
fn drop(&mut self) { }
}
}

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@ -1,21 +1,19 @@
// run-pass
#![allow(deprecated)] // FIXME: switch to `#[may_dangle]` below.
// Example taken from RFC 1238 text
// https://github.com/rust-lang/rfcs/blob/master/text/1238-nonparametric-dropck.md
// #example-of-the-unguarded-escape-hatch
#![feature(dropck_parametricity)]
#![feature(dropck_eyepatch)]
use std::cell::Cell;
struct Concrete<'a>(u32, Cell<Option<&'a Concrete<'a>>>);
struct Foo<T> { data: Vec<T> }
impl<T> Drop for Foo<T> {
// Below is the UGEH attribute
#[unsafe_destructor_blind_to_params]
// Below is the UGEH attribute
unsafe impl<#[may_dangle] T> Drop for Foo<T> {
fn drop(&mut self) { }
}

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@ -1,12 +1,11 @@
// run-pass
#![allow(deprecated)] // FIXME: switch to `#[may_dangle]` below.
// Demonstrate the use of the unguarded escape hatch with a lifetime param
// to assert that destructor will not access any dead data.
//
// Compare with compile-fail/issue28498-reject-lifetime-param.rs
#![feature(dropck_parametricity)]
#![feature(dropck_eyepatch)]
#[derive(Debug)]
struct ScribbleOnDrop(String);
@ -19,10 +18,9 @@ impl Drop for ScribbleOnDrop {
struct Foo<'a>(u32, &'a ScribbleOnDrop);
impl<'a> Drop for Foo<'a> {
#[unsafe_destructor_blind_to_params]
unsafe impl<#[may_dangle] 'a> Drop for Foo<'a> {
fn drop(&mut self) {
// Use of `unsafe_destructor_blind_to_params` is sound,
// Use of `may_dangle` is sound,
// because destructor never accesses `self.1`.
println!("Dropping Foo({}, _)", self.0);
}

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@ -1,5 +1,4 @@
// run-pass
#![allow(deprecated)] // FIXME: switch to `#[may_dangle]` below.
// Demonstrate the use of the unguarded escape hatch with a type param in negative position
// to assert that destructor will not access any dead data.
@ -11,7 +10,7 @@
//
// Compare with run-pass/issue28498-ugeh-with-passed-to-fn.rs
#![feature(dropck_parametricity)]
#![feature(dropck_eyepatch)]
#[derive(Debug)]
struct ScribbleOnDrop(String);
@ -24,10 +23,9 @@ impl Drop for ScribbleOnDrop {
struct Foo<T>(u32, T, Box<for <'r> fn(&'r T) -> String>);
impl<T> Drop for Foo<T> {
#[unsafe_destructor_blind_to_params]
unsafe impl<#[may_dangle] T> Drop for Foo<T> {
fn drop(&mut self) {
// Use of `unsafe_destructor_blind_to_params` is sound,
// Use of `may_dangle` is sound,
// because destructor never passes a `self.1` to the callback
// (in `self.2`) despite having it available.
println!("Dropping Foo({}, _)", self.0);

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@ -1,12 +1,11 @@
// run-pass
#![allow(deprecated)] // FIXME: switch to `#[may_dangle]` below.
// 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)]
#![feature(dropck_eyepatch)]
use std::fmt;
@ -19,12 +18,11 @@ impl Drop for ScribbleOnDrop {
}
}
struct Foo<T:fmt::Debug>(u32, T);
struct Foo<T: fmt::Debug>(u32, T);
impl<T:fmt::Debug> Drop for Foo<T> {
#[unsafe_destructor_blind_to_params]
unsafe impl<#[may_dangle] T: fmt::Debug> Drop for Foo<T> {
fn drop(&mut self) {
// Use of `unsafe_destructor_blind_to_params` is sound,
// Use of `may_dangle` is sound,
// because destructor never accesses the `Debug::fmt` method
// of `T`, despite having it available.
println!("Dropping Foo({}, _)", self.0);

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@ -16,7 +16,7 @@ struct Foo<'a>(u32, &'a ScribbleOnDrop);
impl<'a> Drop for Foo<'a> {
fn drop(&mut self) {
// Use of `unsafe_destructor_blind_to_params` is unsound,
// Use of `may_dangle` is unsound,
// because destructor accesses borrowed data in `self.1`
// and we must force that to strictly outlive `self`.
println!("Dropping Foo({}, {:?})", self.0, self.1);

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@ -16,7 +16,7 @@ struct Foo<T>(u32, T, Box<for <'r> fn(&'r T) -> String>);
impl<T> Drop for Foo<T> {
fn drop(&mut self) {
// Use of `unsafe_destructor_blind_to_params` is unsound,
// Use of `may_dangle` is unsound,
// because we pass `T` to the callback in `self.2`
// below, and thus potentially read from borrowed data.
println!("Dropping Foo({}, {})", self.0, (self.2)(&self.1));

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@ -14,11 +14,11 @@ impl Drop for ScribbleOnDrop {
}
}
struct Foo<T:fmt::Debug>(u32, T);
struct Foo<T: fmt::Debug>(u32, T);
impl<T:fmt::Debug> Drop for Foo<T> {
impl<T: fmt::Debug> Drop for Foo<T> {
fn drop(&mut self) {
// Use of `unsafe_destructor_blind_to_params` is unsound,
// Use of `may_dangle` 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);