Ember variables/namespaces seem not to resolve

I’m reasonably new to ember, I’ve typed a few example programs and I’m now trying a new one. I’m using ember 2.3.1 which i have just installed. It seems that ember variables/keywords do not resolve as they did in the previous versions of ember that I have tried.

This is the app.js generated by ember-cli, the Application and extend are underscored as not resolved:

import Ember from 'ember';
import Resolver from './resolver';
import loadInitializers from 'ember-load-initializers';
import config from './config/environment';

let App;


App = Ember.Application.extend({
  modulePrefix: config.modulePrefix,
  podModulePrefix: config.podModulePrefix,

loadInitializers(App, config.modulePrefix);

export default App;

This is the router.js generated by ember-cli and Router and route are marked as unresolved:

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: config.locationType

Router.map(function() {

export default Router;

I did a global uninstall of ember and a new install and also the similar updates in the project but it didn’t help. What do I need to change to make things resolve again?

I have now figured out why I had this problem. After I had created the new project I opened it in phpStorm and created the tmp directory. I then excluded this directory and the directories bower_components and node_modules from indexing to save time. When I cancelled the exclusion everything went back to normal.