Ensure parens for more await cases (#1595)

src/fast-path.js

@@ -388,7 +388,10 @@ FPp.needsParens = function() {
       }
 
     case "YieldExpression":
-      if (parent.type === "UnaryExpression") {
+      if (
+        parent.type === "UnaryExpression" ||
+        parent.type === "AwaitExpression"
+      ) {
         return true;
       }
     // else fall through
@@ -524,6 +527,7 @@ FPp.needsParens = function() {
         case "UnaryExpression":
         case "LogicalExpression":
         case "BinaryExpression":
+        case "AwaitExpression":
           return true;
 
         case "ConditionalExpression":

tests/async/__snapshots__/jsfmt.spec.js.snap

@@ -67,3 +67,18 @@ async function f() {
 }
 
 `;
+
+exports[`parens.js 1`] = `
+async function *f(){ await (yield x); }
+
+async function f(){ await (() => {}); }
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+async function* f() {
+  await (yield x);
+}
+
+async function f() {
+  await (() => {});
+}
+
+`;

tests/async/parens.js

@@ -0,0 +1,3 @@
+async function *f(){ await (yield x); }
+
+async function f(){ await (() => {}); }