Add test for aligned references from slice iterators

Author: bluss

src/test/run-pass/zero-sized-by-ref-iterator.rs

@@ -0,0 +1,41 @@
+// Copyright 2017 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.
+#![feature(repr_align, attr_literals, core_intrinsics)]
+
+use std::mem::align_of;
+use std::intrinsics::type_name;
+
+fn has_aligned_refs<'a, I, T: 'a>(iterable: I)
+where
+    I: Iterator<Item = &'a T>
+{
+    for elt in iterable {
+        unsafe {
+            assert_eq!((elt as *const T as usize) % align_of::<T>(), 0,
+                       "Assertion failed for type {}", type_name::<T>());
+        }
+    }
+}
+
+fn main() {
+    #[derive(Copy, Clone)]
+    struct Zst;
+
+    #[derive(Copy, Clone)]
+    #[repr(align(64))]
+    struct Aligned;
+
+    has_aligned_refs([Zst; 8].iter());
+    has_aligned_refs([[0f64; 0]; 8].iter());
+    has_aligned_refs([Aligned; 8].iter());
+    has_aligned_refs([Zst; 8].iter_mut().map(|t| &*t));
+    has_aligned_refs([[0f64; 0]; 8].iter_mut().map(|t| &*t));
+    has_aligned_refs([Aligned; 8].iter_mut().map(|t| &*t));
+}