Default Parameters + Destructuring - Pending items

[0xe]

Address items pending from #1640

• Destructuring with defaults in for loops. This should evaluate to 3, instead throws NPE:

function a() {}; (function() { 
            for (let {x = a()} = {}; ; ) { 
                return 3; 
            }
        })()

• Reading [Symbol.iterator] from default array/object

function f([x = 1, y = 2] = {x: 3, y: 4}) {
 return x + y;
 }

This should throw a TypeError as [Symbol.iterator] is not implemented for that object on the rhs, instead uses defaults to return 3.

function f([x = 1, y = 2] = {x: 3, y: 4, 
                              [Symbol.iterator]: function*() { 
                                yield 3; 
                                yield 4; 
                              }}) {
                                return x + y;
                              }

And this should work because we call into iterator to get the default values. Instead we throw a NPE currently.

[p-bakker]

@0xe any chance you'll be picking up this one not that the previous part has been merged?

[0xe]

@0xe any chance you'll be picking up this one not that the previous part has been merged?

Yep. I'm planning on starting with destructuring with defaults in for loops.

[0xe]

Looking to add support for destructuring with defaults in for loops, I found some problems in how default values were transformed. I've created a PR to fix those first: #1708.

[gbrail]

Looks like we have made progress since the last time we updated this issue. Can anyone update where we are with this? I'd like to decide if we're going to fix this in the next week or so or move it to a new release.

[0xe]

Looks like we have made progress since the last time we updated this issue. Can anyone update where we are with this? I'd like to decide if we're going to fix this in the next week or so or move it to a new release.

Sorry, this fell off the radar a bit. I'm still working on fixing this but won't be able to make it by next week.