| // 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()) |
| } |