In assignments, property keys should be evaluated only after checking the object is not null

[andreabergia]

This should throw a TypeError because we are accessing null, but instead it is throwing a MyError:

function MyError() {}
MyError.prototype.toString = () => 'MyError';

var base = null;
var prop = {
    toString: function() {
        throw new MyError();
    }
  };
 
base[prop] = 42;

[gbrail]

This seems like a fairly fundamental thing to fix and I doubt that it'll get changed in time for our next release Does anyone else have a view to a solution here? I'd like to close out a new release in the next few days.

[andreabergia]

I have some ideas, but this requires checking the spec carefully (and probably what other engines do). But I definitely won't get to work on this in the next couple of weeks.