52efe55d04
core::slice was originally written to tolerate overflow (notably, with slices of zero-sized elements), but it was never updated to use wrapping arithmetic when overflow traps were added. Also correctly handle the case of calling .nth() on an Iter with a zero-sized element type. The iterator was assuming that the pointer value of the returned reference was meaningful, but that's not true for zero-sized elements. Fixes #25016.
35 lines
1.3 KiB
Rust
35 lines
1.3 KiB
Rust
// 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.
|
|
|
|
// compile-flags: -C debug-assertions
|
|
|
|
use std::slice;
|
|
|
|
pub fn main() {
|
|
// In a slice of zero-size elements the pointer is meaningless.
|
|
// Ensure iteration still works even if the pointer is at the end of the address space.
|
|
let slice: &[()] = unsafe { slice::from_raw_parts(-5isize as *const (), 10) };
|
|
assert_eq!(slice.len(), 10);
|
|
assert_eq!(slice.iter().count(), 10);
|
|
|
|
// .nth() on the iterator should also behave correctly
|
|
let mut it = slice.iter();
|
|
assert!(it.nth(5).is_some());
|
|
assert_eq!(it.count(), 4);
|
|
|
|
let slice: &mut [()] = unsafe { slice::from_raw_parts_mut(-5isize as *mut (), 10) };
|
|
assert_eq!(slice.len(), 10);
|
|
assert_eq!(slice.iter_mut().count(), 10);
|
|
|
|
let mut it = slice.iter_mut();
|
|
assert!(it.nth(5).is_some());
|
|
assert_eq!(it.count(), 4);
|
|
}
|