InlineSimpleMethods makes a semantic change in ES2015+

[DavidANeil]

Given the following input code:

class Holder {
    constructor() {
        this.val = {internal: true};
        this.context =  {getVal: () => this.val}
    }
}

console.log(new Holder().context.getVal().internal);

Outputs:

class a {
  constructor() {
    this.g = {h:!0};
    this.i = {j:() => this.g};
  }
}
console.log((new a).i.g.h);

The InlineSimpleMethods replaces the call of getVal() with val, which is incorrect because the this in the definition of getVal is not context, but rather Holder.
This is not a problem in ES5, because the arrow function is already rewritten before running this pass.

[blickly]

Wow, thanks for the nice simple repro case!