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Replace unnecessary uses of TraitObject with casts #36005

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merged 1 commit into from
Aug 27, 2016
+9 −38
Merged

Replace unnecessary uses of TraitObject with casts #36005

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9 changes: 2 additions & 7 deletions src/liballoc/boxed.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,6 @@ use core::mem;
use core::ops::{CoerceUnsized, Deref, DerefMut};
use core::ops::{BoxPlace, Boxed, InPlace, Place, Placer};
use core::ptr::{self, Unique};
use core::raw::TraitObject;
use core::convert::From;

/// A value that represents the heap. This is the default place that the `box`
Expand Down Expand Up @@ -428,12 +427,8 @@ impl Box<Any> {
pub fn downcast<T: Any>(self) -> Result<Box<T>, Box<Any>> {
if self.is::<T>() {
unsafe {
// Get the raw representation of the trait object
let raw = Box::into_raw(self);
let to: TraitObject = mem::transmute::<*mut Any, TraitObject>(raw);

// Extract the data pointer
Ok(Box::from_raw(to.data as *mut T))
let raw: *mut Any = Box::into_raw(self);
Ok(Box::from_raw(raw as *mut T))
}
} else {
Err(self)
Expand Down
2 changes: 1 addition & 1 deletion src/liballoc/lib.rs
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Expand Up @@ -91,7 +91,7 @@
#![cfg_attr(stage0, feature(unsafe_no_drop_flag))]
#![feature(unsize)]

#![cfg_attr(not(test), feature(fused, raw, fn_traits, placement_new_protocol))]
#![cfg_attr(not(test), feature(fused, fn_traits, placement_new_protocol))]
#![cfg_attr(test, feature(test, box_heap))]

// Allow testing this library
Expand Down
14 changes: 2 additions & 12 deletions src/libcore/any.rs
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Expand Up @@ -72,8 +72,6 @@
#![stable(feature = "rust1", since = "1.0.0")]

use fmt;
use mem::transmute;
use raw::TraitObject;
use intrinsics;
use marker::Reflect;

Expand Down Expand Up @@ -199,11 +197,7 @@ impl Any {
pub fn downcast_ref<T: Any>(&self) -> Option<&T> {
if self.is::<T>() {
unsafe {
// Get the raw representation of the trait object
let to: TraitObject = transmute(self);

// Extract the data pointer
Some(&*(to.data as *const T))
Some(&*(self as *const Any as *const T))
}
} else {
None
Expand Down Expand Up @@ -240,11 +234,7 @@ impl Any {
pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
if self.is::<T>() {
unsafe {
// Get the raw representation of the trait object
let to: TraitObject = transmute(self);

// Extract the data pointer
Some(&mut *(to.data as *const T as *mut T))
Some(&mut *(self as *mut Any as *mut T))
}
} else {
None
Expand Down
22 changes: 4 additions & 18 deletions src/libstd/error.rs
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Expand Up @@ -54,7 +54,6 @@ use fmt::{self, Debug, Display};
use marker::Reflect;
use mem::transmute;
use num;
use raw::TraitObject;
use str;
use string;

Expand Down Expand Up @@ -326,11 +325,7 @@ impl Error + 'static {
pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
if self.is::<T>() {
unsafe {
// Get the raw representation of the trait object
let to: TraitObject = transmute(self);

// Extract the data pointer
Some(&*(to.data as *const T))
Some(&*(self as *const Error as *const T))
}
} else {
None
Expand All @@ -344,11 +339,7 @@ impl Error + 'static {
pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> {
if self.is::<T>() {
unsafe {
// Get the raw representation of the trait object
let to: TraitObject = transmute(self);

// Extract the data pointer
Some(&mut *(to.data as *const T as *mut T))
Some(&mut *(self as *mut Error as *mut T))
}
} else {
None
Expand Down Expand Up @@ -409,13 +400,8 @@ impl Error {
pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<Error>> {
if self.is::<T>() {
unsafe {
// Get the raw representation of the trait object
let raw = Box::into_raw(self);
let to: TraitObject =
transmute::<*mut Error, TraitObject>(raw);

// Extract the data pointer
Ok(Box::from_raw(to.data as *mut T))
let raw: *mut Error = Box::into_raw(self);
Ok(Box::from_raw(raw as *mut T))
}
} else {
Err(self)
Expand Down