Auto merge of #42364 - alexcrichton:beta-next, r=brson

[beta] Fix regression in `macro_rules!` name matching.

This is a backport of #42005

Author: bors

src/libsyntax/ext/tt/macro_parser.rs

@@ -267,11 +267,12 @@ pub fn parse_failure_msg(tok: Token) -> String {
 
 /// Perform a token equality check, ignoring syntax context (that is, an unhygienic comparison)
 fn token_name_eq(t1 : &Token, t2 : &Token) -> bool {
-    match (t1,t2) {
-        (&token::Ident(id1),&token::Ident(id2))
-        | (&token::Lifetime(id1),&token::Lifetime(id2)) =>
-            id1.name == id2.name,
-        _ => *t1 == *t2
+    if let (Some(id1), Some(id2)) = (t1.ident(), t2.ident()) {
+        id1.name == id2.name
+    } else if let (&token::Lifetime(id1), &token::Lifetime(id2)) = (t1, t2) {
+        id1.name == id2.name
+    } else {
+        *t1 == *t2
     }
 }
 

src/test/run-pass/issue-41803.rs

@@ -0,0 +1,30 @@
+// 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.
+
+/// A compile-time map from identifiers to arbitrary (heterogeneous) expressions
+macro_rules! ident_map {
+    ( $name:ident = { $($key:ident => $e:expr,)* } ) => {
+        macro_rules! $name {
+            $(
+                ( $key ) => { $e };
+            )*
+            // Empty invocation expands to nothing. Needed when the map is empty.
+            () => {};
+        }
+    };
+}
+
+ident_map!(my_map = {
+    main => 0,
+});
+
+fn main() {
+    my_map!(main);
+}