Auto merge of #42902 - petrochenkov:keydcrate, r=jseyfried

Make `$crate` a keyword

Fixes https://github.com/rust-lang/rust/issues/42898

r? @jseyfried or @nrc

src/test/compile-fail/dollar-crate-is-keyword-2.rs

@@ -0,0 +1,23 @@
+// 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.
+
+mod a {}
+
+macro_rules! m {
+    () => {
+        use a::$crate; //~ ERROR unresolved import `a::$crate`
+        use a::$crate::b; //~ ERROR unresolved import `a::$crate::b`
+        type A = a::$crate; //~ ERROR cannot find type `$crate` in module `a`
+    }
+}
+
+m!();
+
+fn main() {}

src/test/compile-fail/dollar-crate-is-keyword.rs

@@ -0,0 +1,24 @@
+// 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.
+
+macro_rules! m {
+    () => {
+        struct $crate {} //~ ERROR expected identifier, found reserved identifier `$crate`
+
+        use $crate; // OK
+                    //~^ WARN `$crate` may not be imported
+        use $crate as $crate; //~ ERROR expected identifier, found reserved identifier `$crate`
+                              //~^ WARN `$crate` may not be imported
+    }
+}
+
+m!();
+
+fn main() {}

src/test/compile-fail/use-self-type.rs

@@ -0,0 +1,21 @@
+// 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.
+
+struct S;
+
+impl S {
+    fn f() {}
+    fn g() {
+        use Self::f; //~ ERROR unresolved import
+        pub(in Self::f) struct Z; //~ ERROR Use of undeclared type or module `Self`
+    }
+}
+
+fn main() {}

src/test/parse-fail/macro-keyword.rs

@@ -10,7 +10,7 @@
 
 // compile-flags: -Z parse-only
 
-fn macro() {  //~ ERROR `macro` is a reserved keyword
+fn macro() {  //~ ERROR expected identifier, found reserved keyword `macro`
 }
 
 pub fn main() {