Move /src/test to /tests

tests/ui/array-slice-vec/slice-of-zero-size-elements.rs

@@ -0,0 +1,53 @@
+// 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())
+}