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// run-pass
#![allow(stable_features)]
// compile-flags: -C debug-assertions
#![feature(iter_to_slice)]
use std::slice;
fn foo<T>(v: &[T]) -> Option<&[T]> {
let mut it = v.iter();
for _ in 0..5 {
let _ = it.next();
}
Some(it.as_slice())
}
fn foo_mut<T>(v: &mut [T]) -> Option<&mut [T]> {
let mut it = v.iter_mut();
for _ in 0..5 {
let _ = it.next();
}
Some(it.into_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);
// Converting Iter to a slice should never have a null pointer
assert!(foo(slice).is_some());
// Test mutable iterators as well
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);
}
assert!(foo_mut(slice).is_some())
}
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