From 2bb24f996f025dccd26e1e5269d932efdeebc72d Mon Sep 17 00:00:00 2001
From: Paul Happ <phapp1988@gmail.com>
Date: Tue, 27 Nov 2018 09:45:06 -0600
Subject: [PATCH] Fix yield expression transform (#9076)

---
 packages/babel-generator/src/node/parentheses.js            | 1 +
 .../test/fixtures/parentheses/yield-expression/input.js     | 4 ++++
 .../test/fixtures/parentheses/yield-expression/output.js    | 6 +++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/babel-generator/src/node/parentheses.js b/packages/babel-generator/src/node/parentheses.js
index 8213fdd92e36..8f7c137f5224 100644
--- a/packages/babel-generator/src/node/parentheses.js
+++ b/packages/babel-generator/src/node/parentheses.js
@@ -166,6 +166,7 @@ export function YieldExpression(node: Object, parent: Object): boolean {
     t.isCallExpression(parent) ||
     t.isMemberExpression(parent) ||
     t.isNewExpression(parent) ||
+    (t.isAwaitExpression(parent) && t.isYieldExpression(node)) ||
     (t.isConditionalExpression(parent) && node === parent.test) ||
     isClassExtendsClause(node, parent)
   );
diff --git a/packages/babel-generator/test/fixtures/parentheses/yield-expression/input.js b/packages/babel-generator/test/fixtures/parentheses/yield-expression/input.js
index b000b972b537..2d6b7957f17c 100644
--- a/packages/babel-generator/test/fixtures/parentheses/yield-expression/input.js
+++ b/packages/babel-generator/test/fixtures/parentheses/yield-expression/input.js
@@ -10,3 +10,7 @@ function* asdf() {
 function* a(b) {
   (yield xhr({ url: "views/test.html" })).data;
 }
+
+(async function* () {
+  await (yield 1);
+});
diff --git a/packages/babel-generator/test/fixtures/parentheses/yield-expression/output.js b/packages/babel-generator/test/fixtures/parentheses/yield-expression/output.js
index 28340375a453..e7c3bcd100df 100644
--- a/packages/babel-generator/test/fixtures/parentheses/yield-expression/output.js
+++ b/packages/babel-generator/test/fixtures/parentheses/yield-expression/output.js
@@ -11,4 +11,8 @@ function* a(b) {
   (yield xhr({
     url: "views/test.html"
   })).data;
-}
\ No newline at end of file
+}
+
+(async function* () {
+  await (yield 1);
+});