Add parenthesis around class expression when left side of call expression (#409)

Fixes #402

src/fast-path.js

@@ -434,6 +434,10 @@ FPp.needsParens = function(assumeExpressionContext) {
         case "ExportDefaultDeclaration":
         case "ExpressionStatement":
           return true;
+        case "CallExpression":
+          if (parent.callee === node) {
+            return true;
+          }
       }
 
       return false;

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

@@ -87,6 +87,13 @@ exports[`test binary.js 1`] = `
 "
 `;
 
+exports[`test call.js 1`] = `
+"(class {})(class {});
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+(class {})(class {});
+"
+`;
+
 exports[`test class_shapes.js 1`] = `
 "/* @flow */
 

tests/classes/call.js

@@ -0,0 +1 @@
+(class {})(class {});