Rollup merge of #49634 - lloydmeta:tests/issue-43058, r=nikomatsakis

Add a test for the fix to issue #43058

Followed the instructions laid out here #43058 (comment)

Author: kennytm

src/test/ui/nll/issue-43058.rs

@@ -0,0 +1,38 @@
+// 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.
+
+// must-compile-successfully
+
+#![feature(nll)]
+
+use std::borrow::Cow;
+
+#[derive(Clone, Debug)]
+struct S<'a> {
+    name: Cow<'a, str>
+}
+
+#[derive(Clone, Debug)]
+struct T<'a> {
+    s: Cow<'a, [S<'a>]>
+}
+
+fn main() {
+    let s1 = [S { name: Cow::Borrowed("Test1") }, S { name: Cow::Borrowed("Test2") }];
+    let b1 = T { s: Cow::Borrowed(&s1) };
+    let s2 = [S { name: Cow::Borrowed("Test3") }, S { name: Cow::Borrowed("Test4") }];
+    let b2 = T { s: Cow::Borrowed(&s2) };
+
+    let mut v = Vec::new();
+    v.push(b1);
+    v.push(b2);
+
+    println!("{:?}", v);
+}