Default export lost when using an arrow function containing a deconstructed object (T7531)

[babel-bot]

Issue originally made by Ryan Duffy (ryan.duffy)

Bug information

• Babel version: 6.11.4

Options

es2015 preset

Input code

export default () => ({
  x: ({x}) => {}
});

Description

With the above code, babel transpiles to a closure without module.exports. Seems to be unique to the combination of exporting an arrow function that returns an object containing a key whose value is an arrow function where the first arg is deconstructed with a key of the same name.

• If the keys are different (x: ({y}) => {}) or the deconstructed key is renamed (e.g. x: ({x: y}) => {}), it doesn't reproduce.
• If you use function in place of either arrow function, it doesn't reproduce.
• If you store the closure into a local variable and then export that, it doesn't reproduce.

Reproducible via the babel repl as well

[danez]

Thanks, duplicate of #4182.