Add a couple of tests

Author: mark-i-m

src/test/compile-fail/macro-at-most-once-rep-ambig.rs

@@ -0,0 +1,26 @@
+// Copyright 2012 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! foo {
+    ($(a)?) => {}
+}
+
+macro_rules! bar {
+    ($(a)?+) => {}
+}
+
+pub fn main() {
+    foo!(a?a?a); //~ ERROR no rules expected the token `?`
+    foo!(a?a); //~ ERROR no rules expected the token `?`
+    foo!(a?); //~ ERROR no rules expected the token `?`
+    bar!(); //~ ERROR no rules expected the token `)`
+    bar!(a?); //~ ERROR no rules expected the token `?`
+}
+

src/test/run-pass/macro-at-most-once-rep.rs

@@ -0,0 +1,25 @@
+// Copyright 2012 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! foo {
+    ($(a)?) => {}
+}
+
+macro_rules! bar {
+    ($(a)?+) => {}
+}
+
+pub fn main() {
+    foo!();
+    foo!(a);
+    bar!(a);
+    bar!(a?a);
+    bar!(a?a?a);
+}