From 0e0cf976c9293627ea318eec6211e62326375abe Mon Sep 17 00:00:00 2001
From: Marcus Klaas <mail@marcusklaas.nl>
Date: Sun, 27 Mar 2016 13:44:08 +0200
Subject: [PATCH] Fix issues with empty macros with curly braces

---
 src/macros.rs          | 12 ++++++------
 tests/source/macros.rs | 19 +++++++++++++++++++
 tests/target/macros.rs | 16 ++++++++++++++++
 3 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/src/macros.rs b/src/macros.rs
index 324c68d750a..620dd9d98f6 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -27,7 +27,7 @@
 use Indent;
 use rewrite::RewriteContext;
 use expr::{rewrite_call, rewrite_array};
-use comment::FindUncommented;
+use comment::{FindUncommented, contains_comment};
 use utils::{CodeMapSpanUtils, wrap_str};
 
 const FORCED_BRACKET_MACROS: &'static [&'static str] = &["vec!"];
@@ -63,11 +63,11 @@ pub fn rewrite_macro(mac: &ast::Mac,
         original_style
     };
 
-    if mac.node.tts.is_empty() {
-        return if let MacroStyle::Parens = style {
-            Some(format!("{}()", macro_name))
-        } else {
-            Some(format!("{}[]", macro_name))
+    if mac.node.tts.is_empty() && !contains_comment(&context.snippet(mac.span)) {
+        return match style {
+            MacroStyle::Parens => Some(format!("{}()", macro_name)),
+            MacroStyle::Brackets => Some(format!("{}[]", macro_name)),
+            MacroStyle::Braces => Some(format!("{}{{}}", macro_name)),
         };
     }
 
diff --git a/tests/source/macros.rs b/tests/source/macros.rs
index 261f02e756f..cafc4522ef7 100644
--- a/tests/source/macros.rs
+++ b/tests/source/macros.rs
@@ -33,4 +33,23 @@ fn main() {
     macrowithbraces! {dont,    format, me}
 
     x!(fn);
+
+    some_macro!(
+        
+    );
+
+    some_macro![
+    ];
+
+    some_macro!{
+        // comment
+    };
+
+    some_macro!{
+        // comment
+    };
+}
+
+impl X {
+    empty_invoc!{}
 }
diff --git a/tests/target/macros.rs b/tests/target/macros.rs
index 4d99ede9f50..a463947d985 100644
--- a/tests/target/macros.rs
+++ b/tests/target/macros.rs
@@ -39,4 +39,20 @@ fn main() {
     macrowithbraces! {dont,    format, me}
 
     x!(fn);
+
+    some_macro!();
+
+    some_macro![];
+
+    some_macro!{
+        // comment
+    };
+
+    some_macro!{
+        // comment
+    };
+}
+
+impl X {
+    empty_invoc!{}
 }