diff --git a/substrate/core/primitives/src/lib.rs b/substrate/core/primitives/src/lib.rs
index c2d23050f9..0a1f80aaa9 100644
--- a/substrate/core/primitives/src/lib.rs
+++ b/substrate/core/primitives/src/lib.rs
@@ -26,9 +26,9 @@
 /// Can be used to create a `HashMap`.
 #[macro_export]
 macro_rules! map {
-	($( $name:expr => $value:expr ),*) => (
+	($( $name:expr => $value:expr ),* $(,)? ) => (
 		vec![ $( ( $name, $value ) ),* ].into_iter().collect()
-	)
+	);
 }
 
 use rstd::prelude::*;