Fix #[derive] for empty structs with braces

src/test/auxiliary/custom_derive_plugin_attr.rs

@@ -73,7 +73,7 @@ fn expand(cx: &mut ExtCtxt,
 fn totalsum_substructure(cx: &mut ExtCtxt, trait_span: Span,
                          substr: &Substructure) -> P<ast::Expr> {
     let fields = match *substr.fields {
-        Struct(ref fs) | EnumMatching(_, _, ref fs) => fs,
+        Struct(_, ref fs) | EnumMatching(_, _, ref fs) => fs,
         _ => cx.span_bug(trait_span, "impossible substructure")
     };
 

src/test/run-pass/empty-struct-braces-derive.rs

@@ -0,0 +1,45 @@
+// Copyright 2015 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.
+
+// `#[derive(Trait)]` works for empty structs/variants with braces
+
+#![feature(braced_empty_structs)]
+#![feature(rustc_private)]
+
+extern crate serialize as rustc_serialize;
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash,
+         Default, Debug, RustcEncodable, RustcDecodable)]
+struct S {}
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash,
+         Debug, RustcEncodable, RustcDecodable)]
+enum E {
+    V {},
+    U,
+}
+
+fn main() {
+    let s = S {};
+    let s1 = s;
+    let s2 = s.clone();
+    assert_eq!(s, s1);
+    assert_eq!(s, s2);
+    assert!(!(s < s1));
+    assert_eq!(format!("{:?}", s), "S");
+
+    let e = E::V {};
+    let e1 = e;
+    let e2 = e.clone();
+    assert_eq!(e, e1);
+    assert_eq!(e, e2);
+    assert!(!(e < e1));
+    assert_eq!(format!("{:?}", e), "V");
+}