Auto merge of #29110 - apasel422:shared, r=alexcrichton

Fixes #29037.
Fixes #29106.

r? @pnkfelix 
CC @Gankro

src/test/compile-fail/issue-29106.rs

@@ -0,0 +1,34 @@
+// Copyright 2015 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.
+
+use std::rc::Rc;
+use std::sync::Arc;
+
+struct Foo<'a>(&'a String);
+
+impl<'a> Drop for Foo<'a> {
+    fn drop(&mut self) {
+        println!("{:?}", self.0);
+    }
+}
+
+fn main() {
+    {
+        let (y, x);
+        x = "alive".to_string();
+        y = Arc::new(Foo(&x)); //~ ERROR `x` does not live long enough
+    }
+
+    {
+        let (y, x);
+        x = "alive".to_string();
+        y = Rc::new(Foo(&x)); //~ ERROR `x` does not live long enough
+    }
+}

src/test/run-pass/issue-29037.rs

@@ -0,0 +1,32 @@
+// Copyright 2015 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.
+
+// This test ensures that each pointer type `P<X>` is covariant in `X`.
+
+use std::rc::Rc;
+use std::sync::Arc;
+
+fn a<'r>(x: Box<&'static str>) -> Box<&'r str> {
+    x
+}
+
+fn b<'r, 'w>(x: &'w &'static str) -> &'w &'r str {
+    x
+}
+
+fn c<'r>(x: Arc<&'static str>) -> Arc<&'r str> {
+    x
+}
+
+fn d<'r>(x: Rc<&'static str>) -> Rc<&'r str> {
+    x
+}
+
+fn main() {}