Add NLL tests for rust-lang#46557 and rust-lang#38899

Closes rust-lang#47366

Adapt the sample code from the issues into mir-borrowck/nll test cases.

src/test/ui/nll/borrowed-referent-issue-38899.rs

@@ -0,0 +1,32 @@
+// Copyright 2018 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.
+
+// Regression test for issue #38899
+
+// compile-flags:-Znll -Zborrowck=mir -Zverbose
+
+#![feature(nll)]
+#![allow(dead_code)]
+
+pub struct Block<'a> {
+ current: &'a u8,
+ unrelated: &'a u8,
+}
+
+fn bump<'a>(mut block: &mut Block<'a>) {
+ let x = &mut block;
+ println!("{}", x.current);
+ let p: &'a u8 = &*block.current;
+ //~^ ERROR cannot borrow `*block.current` as immutable because it is also borrowed as mutable
+ drop(x);
+ drop(p);
+}
+
+fn main() {}

src/test/ui/nll/borrowed-referent-issue-38899.stderr

@@ -0,0 +1,11 @@
+error[E0502]: cannot borrow `*block.current` as immutable because it is also borrowed as mutable
+ --> $DIR/borrowed-referent-issue-38899.rs:26:21
+ |
+24 | let x = &mut block;
+ | ---------- mutable borrow occurs here
+25 | println!("{}", x.current);
+26 | let p: &'a u8 = &*block.current;
+ | ^^^^^^^^^^^^^^^ immutable borrow occurs here
+
+error: aborting due to previous error
+

src/test/ui/nll/return-ref-mut-issue-46557.rs

@@ -0,0 +1,23 @@
+// Copyright 2018 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.
+
+// Regression test for issue #46557
+
+// compile-flags:-Znll -Zborrowck=mir -Zverbose
+
+#![feature(nll)]
+#![allow(dead_code)]
+
+fn gimme_static_mut() -> &'static mut u32 {
+ let ref mut x = 1234543; //~ ERROR borrowed value does not live long enough [E0597]
+ x
+}
+
+fn main() {}

src/test/ui/nll/return-ref-mut-issue-46557.stderr

@@ -0,0 +1,13 @@
+error[E0597]: borrowed value does not live long enough
+ --> $DIR/return-ref-mut-issue-46557.rs:19:21
+ |
+19 | let ref mut x = 1234543; //~ ERROR borrowed value does not live long enough [E0597]
+ | ^^^^^^^ temporary value does not live long enough
+20 | x
+21 | }
+ | - temporary value only lives until here
+ |
+ = note: borrowed value must be valid for lifetime '_#2r...
+
+error: aborting due to previous error
+