Improve let check in for..of

src/language-js/needs-parens.js

@@ -70,9 +70,8 @@ function needsParens(path, options) {
     // `for ((async) of []);` and `for ((let) of []);`
     if (
       name === "left" &&
-      (node.name === "async" || node.name === "let") &&
-      parent.type === "ForOfStatement" &&
-      !parent.await
+      ((node.name === "async" && !parent.await) || node.name === "let") &&
+      parent.type === "ForOfStatement"
     ) {
       return true;
     }

tests/format/js/identifier/for-of/__snapshots__/jsfmt.spec.js.snap

@@ -7,13 +7,15 @@ printWidth: 80
                                                                                 | printWidth
 =====================================input======================================
 async function a() {
+  for await((let) of foo);
   for await((let).a of foo);
   for await((let)[a] of foo);
   for await((let)()[a] of foo);
 }
 
 =====================================output=====================================
 async function a() {
+  for await ((let) of foo);
   for await ((let).a of foo);
   for await ((let)[a] of foo);
   for await ((let)()[a] of foo);
@@ -40,6 +42,8 @@ for (letFoo of foo);
 for ((let.a) in foo);
 for ((let[a]) in foo);
 
+for (let of of let);
+
 =====================================output=====================================
 for ((let) of foo);
 for (foo of let);
@@ -53,5 +57,7 @@ for (letFoo of foo);
 for (let.a in foo);
 for ((let)[a] in foo);
 
+for (let of of let);
+
 ================================================================================
 `;

tests/format/js/identifier/for-of/await.js

@@ -1,4 +1,5 @@
 async function a() {
+  for await((let) of foo);
   for await((let).a of foo);
   for await((let)[a] of foo);
   for await((let)()[a] of foo);

tests/format/js/identifier/for-of/let.js

@@ -9,3 +9,5 @@ for (letFoo of foo);
 
 for ((let.a) in foo);
 for ((let[a]) in foo);
+
+for (let of of let);