From 82661cd2cebc1c42b042dd01e468a28fc80de92d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bastian=20K=C3=B6cher?= <bkchr@users.noreply.github.com>
Date: Tue, 7 Jan 2020 12:48:05 +0100
Subject: [PATCH] `decl_event` support trailing comma in args (#4554)

---
 substrate/frame/support/src/event.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/substrate/frame/support/src/event.rs b/substrate/frame/support/src/event.rs
index aac3a5955e..3ff6d4ab45 100644
--- a/substrate/frame/support/src/event.rs
+++ b/substrate/frame/support/src/event.rs
@@ -304,7 +304,7 @@ macro_rules! __events_to_metadata {
 	(
 		$( $metadata:expr ),*;
 		$( #[doc = $doc_attr:tt] )*
-		$event:ident $( ( $( $param:path ),* ) )*,
+		$event:ident $( ( $( $param:path ),* $(,)? ) )*,
 		$( $rest:tt )*
 	) => {
 		$crate::__events_to_metadata!(
@@ -704,6 +704,10 @@ mod tests {
 				OriginRenamed = <T as Trait>::Origin,
 			{
 				TestEvent(BalanceRenamed, OriginRenamed),
+				TrailingCommaInArgs(
+					u32,
+					u32,
+				),
 			}
 		);
 	}