Added cfail test

Changed error to 'use of trait `{}` as a struct constructor'

Author: wickerwaka

src/librustc/middle/typeck/check/mod.rs

@@ -4000,7 +4000,7 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
             }
             Some(def::DefTrait(def_id)) => {
                 span_err!(tcx.sess, path.span, E0159,
-                    "`{}` is a trait not a structure",
+                    "use of trait `{}` as a struct constructor",
                     pprust::path_to_string(path));
                 check_struct_fields_on_error(fcx,
                                              id,

src/test/compile-fail/trait-as-struct-constructor.rs

@@ -0,0 +1,17 @@
+// Copyright 2014 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.
+
+trait TraitNotAStruct { }
+
+fn main() {
+    TraitNotAStruct{ value: 0 };
+    //~^ ERROR: use of trait `TraitNotAStruct` as a struct constructor [E0159]
+}
+