Returned async fat-arrow function with argument destructuring gets the parent function's arguments

[jetpacmonkey]

It seems like something's going wrong with a combination of canonical arguments, argument destructuring, and async-to-generator.

Input Code

// This one calls the inner function with the outer function's arguments
function breaks(fn) {
  return async (...args) => {
    return fn(...args);
  };
}

// This passes the arguments along as expected
function works(fn) {
  return async (...args) => {
    const dummy = args;
    return fn(...args);
  };
}

REPL link

Babel Configuration (.babelrc, package.json, cli command)

{
  "presets": ["es2015", "stage-2"]
}

Expected Behavior

Both calls should log { data: "_str_" } to the console

Current Behavior

The first one, which doesn't access args, is logging

{
  "data": `_function (a) {
  return { data: \'_\' + a + \'_\' };
}_`
}

Possible Solution

It seems like something in async-to-generator is conflicting with... something else. Sorry, I'm not very familiar with babel's internals.

Context

I was trying to write a wrapper function, which would work regardless of whether the inner function returned a promise or not. I noticed the inner function was getting the wrong arguments, so I added a console.log(args) in there to try and debug, and... all of the sudden everything worked as expected.

Your Environment

Reproduced in the REPL, so I'm not sure how relevant this is, but here you go...

software	version
Babel	6.22.0
node	7.7.1
npm	4.1.2
Operating System	macOS 10.12.3

[babel-bot]

Hey @jetpacmonkey! We really appreciate you taking the time to report an issue. The collaborators
on this project attempt to help as many people as possible, but we're a limited number of volunteers,
so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack
community that typically always has someone willing to help. You can sign-up here
for an invite.

[existentialism]

Thanks for the issue @jetpacmonkey!

We're actively tracking this issue in #4219 (and all the linked issues, including #5330 are related).

We will try to get it addressed as soon as possible, but welcome any help!

[jetpacmonkey]

Whoops, thanks! I blame Github's weak issue search for my oversight 😏

[hzoo]

All good, we really should of fixed this earlier 😄