Fix parens around anonymous functions (#297)

src/fast-path.js

@@ -373,6 +373,7 @@ FPp.needsParens = function(assumeExpressionContext) {
       }
 
       switch (parent.type) {
+        case "ExpressionStatement":
         case "MemberExpression":
         case "TaggedTemplateExpression":
         case "UnaryExpression":

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

@@ -40,11 +40,11 @@ async function* delegate_yield() {
   }
   yield* inner();
 }
-async () => {
+(async () => {
   for await (const x of delegate_yield()) {
     (x: void); // error: number ~> void
   }
-};
+});
 
 async function* delegate_return() {
   async function* inner() {
@@ -197,13 +197,13 @@ async function* catch_return() {
   }
 }
 
-async () => {
+(async () => {
   catch_return().throw(\"\").then(({ value }) => {
     if (value !== undefined) {
       (value: void); // error: number ~> void
     }
   });
-};
+});
 
 async function* yield_return() {
   try {
@@ -214,12 +214,12 @@ async function* yield_return() {
   }
 }
 
-async () => {
+(async () => {
   yield_return().throw(\"\").then(({ value }) => {
     if (value !== undefined) {
       (value: void); // error: number ~> void
     }
   });
-};
+});
 "
 `;

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

@@ -370,6 +370,7 @@ export default (function() {})();
 (function() {})()\`\`;
 (function() {})\`\`;
 new (function() {});
+(function() {})
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 (function() {
 }).length;
@@ -383,6 +384,8 @@ export default (function() {
 })\`\`;
 new (function() {
 })();
+(function() {
+});
 "
 `;
 

tests/function/function_expression.js

@@ -4,3 +4,4 @@ export default (function() {})();
 (function() {})()``;
 (function() {})``;
 new (function() {});
+(function() {})

tests/predicates-parsing/__snapshots__/jsfmt.spec.js.snap

@@ -112,14 +112,14 @@ var a0 = (x: mixed) => x !== null;
 
 var a1 = (x: mixed): %checks => x !== null;
 
-(x): %checks => x !== null;
+((x): %checks => x !== null);
 
 const insert_a_really_big_predicated_arrow_function_name_here = (x): %checks =>
   x !== null;
 
 declare var x;
 x;
-checks => 123;
+(checks => 123);
 
 type checks = any;