reject macros with empty repetitions

src/test/compile-fail/issue-5067.rs

@@ -0,0 +1,62 @@
+// 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.
+
+macro_rules! foo {
+    ( $()* ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( $()+ ) => {};
+    //~^ ERROR repetition matches empty token tree
+
+    ( $(),* ) => {}; // PASS
+    ( $(),+ ) => {}; // PASS
+
+    ( [$()*] ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( [$()+] ) => {};
+    //~^ ERROR repetition matches empty token tree
+
+    ( [$(),*] ) => {}; // PASS
+    ( [$(),+] ) => {}; // PASS
+
+    ( $($()* $(),* $(a)* $(a),* )* ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( $($()* $(),* $(a)* $(a),* )+ ) => {};
+    //~^ ERROR repetition matches empty token tree
+
+    ( $(a     $(),* $(a)* $(a),* )* ) => {}; // PASS
+    ( $($(a)+ $(),* $(a)* $(a),* )+ ) => {}; // PASS
+
+    ( $(a $()+)* ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( $(a $()*)+ ) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+
+// --- Original Issue --- //
+
+macro_rules! make_vec {
+    (a $e1:expr $($(, a $e2:expr)*)*) => ([$e1 $($(, $e2)*)*]);
+    //~^ ERROR repetition matches empty token tree
+}
+
+fn main() {
+    let _ = make_vec!(a 1, a 2, a 3);
+}
+
+
+// --- Minified Issue --- //
+
+macro_rules! m {
+    ( $()* ) => {}
+    //~^ ERROR repetition matches empty token tree
+}
+
+m!();