diff --git a/src/libsyntax/diagnostics/macros.rs b/src/libsyntax/diagnostics/macros.rs
index 8c2d2a251aab..669b930ecc92 100644
--- a/src/libsyntax/diagnostics/macros.rs
+++ b/src/libsyntax/diagnostics/macros.rs
@@ -73,5 +73,8 @@ macro_rules! register_diagnostics {
 macro_rules! register_long_diagnostics {
     ($($code:tt: $description:tt),*) => (
         $(register_diagnostic! { $code, $description })*
+    );
+    ($($code:tt: $description:tt),*,) => (
+        $(register_diagnostic! { $code, $description })*
     )
 }