From d47f3be42ec26fc0a0757bdbb4ebb97a97a71316 Mon Sep 17 00:00:00 2001
From: Jason Freeman <jfreeman@microsoft.com>
Date: Wed, 22 Apr 2015 14:11:01 -0700
Subject: [PATCH] Make expression optional in YieldExpression

---
 src/compiler/types.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 86e680ca8b0..a11d97c45fb 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -660,7 +660,7 @@ module ts {
 
     export interface YieldExpression extends Expression {
         asteriskToken?: Node;
-        expression: Expression;
+        expression?: Expression;
     }
 
     export interface BinaryExpression extends Expression {