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Use unsized coercions for null ptr tests

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This commit is contained in:
Josh Stone 2017-09-30 14:45:18 -07:00
parent 5c6118339a
commit 40a678d8db
1 changed files with 41 additions and 25 deletions
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66
src/libcore/tests/ptr.rs
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@ -8,26 +8,9 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use core::mem;
use core::ptr::*;
use core::cell::RefCell;
/// Create a null pointer to a mutable slice. This is implemented like
/// `slice::from_raw_parts_mut`, which we can't use directly because
/// having a null `&mut [T]` even temporarily is UB.
fn null_slice<T>() -> *mut [T] {
unsafe {
#[repr(C)]
struct Repr<T> {
pub data: *mut T,
pub len: usize,
}
mem::transmute(Repr { data: null_mut::<T>(), len: 0 })
}
}
#[test]
fn test() {
unsafe {
@ -80,7 +63,7 @@ fn test_is_null() {
let mq = unsafe { mp.offset(1) };
assert!(!mq.is_null());
// Pointers to unsized types
// Pointers to unsized types -- slices
let s: &mut [u8] = &mut [1, 2, 3];
let cs: *const [u8] = s;
assert!(!cs.is_null());
@ -94,11 +77,24 @@ fn test_is_null() {
let mz: *mut [u8] = &mut [];
assert!(!mz.is_null());
let ncs: *const [u8] = null_slice();
let ncs: *const [u8] = null::<[u8; 3]>();
assert!(ncs.is_null());
let nms: *mut [u8] = null_slice();
let nms: *mut [u8] = null_mut::<[u8; 3]>();
assert!(nms.is_null());
// Pointers to unsized types -- trait objects
let ci: *const ToString = &3;
assert!(!ci.is_null());
let mi: *mut ToString = &mut 3;
assert!(!mi.is_null());
let nci: *const ToString = null::<isize>();
assert!(nci.is_null());
let nmi: *mut ToString = null_mut::<isize>();
assert!(nmi.is_null());
}
#[test]
@ -123,7 +119,7 @@ fn test_as_ref() {
assert_eq!(p.as_ref().unwrap(), &2);
}
// Pointers to unsized types
// Pointers to unsized types -- slices
let s: &mut [u8] = &mut [1, 2, 3];
let cs: *const [u8] = s;
assert_eq!(cs.as_ref(), Some(&*s));
@ -137,11 +133,24 @@ fn test_as_ref() {
let mz: *mut [u8] = &mut [];
assert_eq!(mz.as_ref(), Some(&[][..]));
let ncs: *const [u8] = null_slice();
let ncs: *const [u8] = null::<[u8; 3]>();
assert_eq!(ncs.as_ref(), None);
let nms: *mut [u8] = null_slice();
let nms: *mut [u8] = null_mut::<[u8; 3]>();
assert_eq!(nms.as_ref(), None);
// Pointers to unsized types -- trait objects
let ci: *const ToString = &3;
assert!(ci.as_ref().is_some());
let mi: *mut ToString = &mut 3;
assert!(mi.as_ref().is_some());
let nci: *const ToString = null::<isize>();
assert!(nci.as_ref().is_none());
let nmi: *mut ToString = null_mut::<isize>();
assert!(nmi.as_ref().is_none());
}
}
@ -161,7 +170,7 @@ fn test_as_mut() {
assert!(p.as_mut().unwrap() == &mut 2);
}
// Pointers to unsized types
// Pointers to unsized types -- slices
let s: &mut [u8] = &mut [1, 2, 3];
let ms: *mut [u8] = s;
assert_eq!(ms.as_mut(), Some(s));
@ -169,8 +178,15 @@ fn test_as_mut() {
let mz: *mut [u8] = &mut [];
assert_eq!(mz.as_mut(), Some(&mut [][..]));
let nms: *mut [u8] = null_slice();
let nms: *mut [u8] = null_mut::<[u8; 3]>();
assert_eq!(nms.as_mut(), None);
// Pointers to unsized types -- trait objects
let mi: *mut ToString = &mut 3;
assert!(mi.as_mut().is_some());
let nmi: *mut ToString = null_mut::<isize>();
assert!(nmi.as_mut().is_none());
}
}