Add noImplicitThis in default tsconfig

[inkless]

This is related to microsoft/TypeScript#14518
When noImplicitThis is not on, this is not ThisType<T>, so we should turn on noImplicitThis by default

[chriskrycho]

Ohhh, interesting. I'll see how this behaves in my app, and will merge after confirming. Edit: I should add that I think this fix one major annoyance I've had for quite some time!

Thank you for the contribution!

[chriskrycho]

Curiously, this fixes it nicely for the EmberObject.extend({ ... }) case but doesn't help at all with ES6 classes. It's a nice win for the non-class variant, though, so I'll take it gladly. Thanks again!

[dwickern]

What's wrong with ES6 classes?

[chriskrycho]

@dwickern without using a this binding, you end up with errors like this:

The only way around it I've found so far is explicitly naming this:

import Component from '@ember/component';

export default class MyFoo extends Component {
  thingToSay = 'Hello';

  sayIt(this: MyFoo, toSomeone: string) {
    const thingToSay = this.get('thingToSay'); // errors without `this: MyFoo` above
    alert(`${thingToSay} ${toSomeone}`);
  }
}  

[dwickern]

Are you using strictFunctionTypes?

[chriskrycho]

I had no been, but turning it on has no effect on this error, either.