Fix some parens cases for UpdateExpressions (#381)

src/fast-path.js

@@ -216,13 +216,24 @@ FPp.needsParens = function(assumeExpressionContext) {
   }
 
   switch (node.type) {
-    case "UpdateExpression":
     case "SpreadElement":
     case "SpreadProperty":
       return parent.type === "MemberExpression" &&
         name === "object" &&
         parent.object === node;
 
+    case "UpdateExpression":
+      switch (parent.type) {
+        case "MemberExpression":
+          return name === "object" && parent.object === node;
+
+        case "CallExpression":
+        case "NewExpression":
+          return true;
+
+        return false;
+      }
+
     case "UnaryExpression":
       switch (parent.type) {
         case "UnaryExpression":

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

@@ -1,6 +1,10 @@
 exports[`test update_expression.js 1`] = `
 "(this.x++).toString()
+new (r++);
+(x++)();
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 (this.x++).toString();
+new (r++)();
+(x++)();
 "
 `;

tests/update_expression/update_expression.js

@@ -1 +1,3 @@
 (this.x++).toString()
+new (r++);
+(x++)();