From 37f82a0c9545dcfed01ee87f906b221fe7f2c5f6 Mon Sep 17 00:00:00 2001
From: topecongiro <seuchida@gmail.com>
Date: Mon, 19 Feb 2018 14:08:33 +0900
Subject: [PATCH] Skip formatting macro_rules! that are not using {}

---
 rustfmt-core/src/macros.rs               | 3 +++
 rustfmt-core/tests/source/macro_rules.rs | 9 +++++++++
 rustfmt-core/tests/target/macro_rules.rs | 9 +++++++++
 3 files changed, 21 insertions(+)

diff --git a/rustfmt-core/src/macros.rs b/rustfmt-core/src/macros.rs
index a8a8c28c585..0633c223c5f 100644
--- a/rustfmt-core/src/macros.rs
+++ b/rustfmt-core/src/macros.rs
@@ -294,6 +294,9 @@ pub fn rewrite_macro_def(
     span: Span,
 ) -> Option<String> {
     let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
+    if snippet.as_ref().map_or(true, |s| s.ends_with(";")) {
+        return snippet;
+    }
 
     let mut parser = MacroParser::new(def.stream().into_trees());
     let parsed_def = match parser.parse() {
diff --git a/rustfmt-core/tests/source/macro_rules.rs b/rustfmt-core/tests/source/macro_rules.rs
index 02c9717e11e..4900574c4eb 100644
--- a/rustfmt-core/tests/source/macro_rules.rs
+++ b/rustfmt-core/tests/source/macro_rules.rs
@@ -68,3 +68,12 @@ macro_rules! m {
         $line3_xxxxxxxxxxxxxxxxx: expr,
     ) => {};
 }
+
+// #2466
+// Skip formatting `macro_rules!` that are not using `{}`.
+macro_rules! m (
+    () => ()
+);
+macro_rules! m [
+    () => ()
+];
diff --git a/rustfmt-core/tests/target/macro_rules.rs b/rustfmt-core/tests/target/macro_rules.rs
index b2f4fc067ac..e6f779d8a03 100644
--- a/rustfmt-core/tests/target/macro_rules.rs
+++ b/rustfmt-core/tests/target/macro_rules.rs
@@ -59,3 +59,12 @@ macro_rules! m {
         $line3_xxxxxxxxxxxxxxxxx: expr,
     ) => {};
 }
+
+// #2466
+// Skip formatting `macro_rules!` that are not using `{}`.
+macro_rules! m (
+    () => ()
+);
+macro_rules! m [
+    () => ()
+];
-- 
2.44.0