Add test

Author: Manishearth

src/test/ui/edition-lint-paths.rs

@@ -0,0 +1,41 @@
+// 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.
+
+#![feature(crate_in_paths)]
+#![deny(absolute_path_starting_with_module)]
+#![allow(unused)]
+
+pub mod foo {
+    use ::bar::Bar;
+    //~^ ERROR Absolute
+    //~| WARN this was previously accepted
+    use super::bar::Bar2;
+    use crate::bar::Bar3;
+}
+
+
+use bar::Bar;
+//~^ ERROR Absolute
+//~| WARN this was previously accepted
+
+pub mod bar {
+    pub struct Bar;
+    pub type Bar2 = Bar;
+    pub type Bar3 = Bar;
+}
+
+fn main() {
+    let x = ::bar::Bar;
+    //~^ ERROR Absolute
+    //~| WARN this was previously accepted
+    let x = bar::Bar;
+    let x = ::crate::bar::Bar;
+    let x = self::bar::Bar;
+}

src/test/ui/edition-lint-paths.stderr

@@ -0,0 +1,34 @@
+error: Absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition
+  --> $DIR/edition-lint-paths.rs:16:9
+   |
+LL |     use ::bar::Bar;
+   |         ^^^^^^^^^^ help: use `crate`: `crate::bar::Bar`
+   |
+note: lint level defined here
+  --> $DIR/edition-lint-paths.rs:12:9
+   |
+LL | #![deny(absolute_path_starting_with_module)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in the 2018 edition!
+   = note: for more information, see issue TBD
+
+error: Absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition
+  --> $DIR/edition-lint-paths.rs:24:5
+   |
+LL | use bar::Bar;
+   |     ^^^^^^^^ help: use `crate`: `crate::bar::Bar`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in the 2018 edition!
+   = note: for more information, see issue TBD
+
+error: Absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition
+  --> $DIR/edition-lint-paths.rs:35:13
+   |
+LL |     let x = ::bar::Bar;
+   |             ^^^^^^^^^^ help: use `crate`: `crate::bar::Bar`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in the 2018 edition!
+   = note: for more information, see issue TBD
+
+error: aborting due to 3 previous errors
+