syntax: Extra diagnostics for _ used in an identifier position

src/test/parse-fail/issue-32501.rs

@@ -0,0 +1,21 @@
+// 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.
+
+// compile-flags: -Z parse-only
+
+fn main() {
+    let a = 0;
+    let _b = 0;
+    let _ = 0;
+    let mut b = 0;
+    let mut _b = 0;
+    let mut _ = 0; //~ ERROR expected identifier, found `_`
+    //~^ NOTE `_` is a wildcard pattern, not an identifier
+}

src/test/parse-fail/paamayim-nekudotayim.rs

@@ -13,5 +13,5 @@
 // http://phpsadness.com/sad/1
 
 fn main() {
-    ::; //~ ERROR expected ident, found `;`
+    ::; //~ ERROR expected identifier, found `;`
 }

src/test/parse-fail/unboxed-closure-sugar-used-on-struct-3.rs

@@ -24,7 +24,7 @@ fn bar() {
     let b = Box::Bar::<isize,usize>::new(); // OK
 
     let b = Box::Bar::()::new();
-    //~^ ERROR expected ident, found `(`
+    //~^ ERROR expected identifier, found `(`
 }
 
 fn main() { }