Rollup merge of rust-lang#45635 - virgil-palanciuc:master, r=kennytm

Add test for rust-lang#44953

Added the requested test - trying to see if it passes; my local build fails, but not sure why - the nightly shows this output, but in my build the compilation error changed.

Fixes rust-lang#44953.

src/test/ui-fulldeps/issue-44953/issue-44953.rs

@@ -0,0 +1,20 @@
+// Copyright 2016 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(proc_macro)]
+#![allow(unused_macros)]
+
+#[macro_use] extern crate log;
+
+pub fn main() {
+    info!("This is a log message.");
+}

src/test/ui-fulldeps/issue-44953/issue-44953.stderr

@@ -0,0 +1,19 @@
+error: use of unstable library feature 'rustc_private': this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead? (see issue #27812)
+  --> $DIR/issue-44953.rs:16:14
+   |
+16 | #[macro_use] extern crate log;
+   |              ^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(rustc_private)] to the crate attributes to enable
+
+error: use of unstable library feature 'rustc_private': this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead? (see issue #27812)
+  --> $DIR/issue-44953.rs:19:5
+   |
+19 |     info!("This is a log message.");
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(rustc_private)] to the crate attributes to enable
+   = note: this error originates in a macro outside of the current crate (run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
+