From 34f33ec789297716995045f7067aeb4d77947d89 Mon Sep 17 00:00:00 2001
From: est31 <MTest31@outlook.com>
Date: Sun, 13 Nov 2016 17:55:17 +0100
Subject: [PATCH] Fix empty lifetime list or one with trailing comma being
 rejected

Fixes #37733
---
 src/libsyntax/parse/parser.rs    |  6 +++---
 src/test/run-pass/issue-37733.rs | 15 +++++++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)
 create mode 100644 src/test/run-pass/issue-37733.rs

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index b80aa667be6a1..064c93c2866e9 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -1943,12 +1943,12 @@ impl<'a> Parser<'a> {
                     if let Some(recv) = followed_by_ty_params {
                         assert!(recv.is_empty());
                         *recv = attrs;
-                    } else {
+                        debug!("parse_lifetime_defs ret {:?}", res);
+                        return Ok(res);
+                    } else if !attrs.is_empty() {
                         let msg = "trailing attribute after lifetime parameters";
                         return Err(self.fatal(msg));
                     }
-                    debug!("parse_lifetime_defs ret {:?}", res);
-                    return Ok(res);
                 }
             }
 
diff --git a/src/test/run-pass/issue-37733.rs b/src/test/run-pass/issue-37733.rs
new file mode 100644
index 0000000000000..358b93254de90
--- /dev/null
+++ b/src/test/run-pass/issue-37733.rs
@@ -0,0 +1,15 @@
+// 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.
+
+type A = for<> fn();
+
+type B = for<'a,> fn();
+
+pub fn main() {}