Keep parens around Unary and Update Expressions (#3989)

src/common/fast-path.js

@@ -265,6 +265,9 @@ FastPath.prototype.needsParens = function(options) {
         case "BinaryExpression":
           return parent.operator === "**" && name === "left";
 
+        case "TSNonNullExpression":
+          return true;
+
         default:
           return false;
       }

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

@@ -20,6 +20,7 @@ const {
 exports[`parens.ts 1`] = `
 (a ? b : c) ![tokenKey];
 (a || b) ![tokenKey];
+(void 0)!;
 
 async function f() {
     return (await foo())!;
@@ -31,6 +32,7 @@ function* g() {
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 (a ? b : c)![tokenKey];
 (a || b)![tokenKey];
+(void 0)!;
 
 async function f() {
   return (await foo())!;

tests/typescript_non_null/parens.ts

@@ -1,5 +1,6 @@
 (a ? b : c) ![tokenKey];
 (a || b) ![tokenKey];
+(void 0)!;
 
 async function f() {
     return (await foo())!;