Use of undefined-returning-function result in ES2015 CommonJS module transform (T7565)

[babel-bot]

Issue originally made by Justin Johansson (justinjohansson)

Bug information

• Babel version: 6.11.4 (babel-core 6.13.2)
• Node version: v6.4.0
• npm version: v6.4.0

Input code

Bug shows up when transpiling following input code with ES2015 CommonJS module transform plugin.

/* file: bar.js */

export { yy, zz };

var yy = 0;
var zz = yy++;

Description

Bug is apparent by visual inspection of code in babel-plugin-transform-es2015-modules-commonjs/src/index.js line 122 in UpdateExpression:

let newPaths = path.replaceWithMultiple(t.sequenceExpression(nodes));
for (const newPath of newPaths) this.requeueInParent(newPath);

replaceWithMultiple is a method which always returns undefined. The following for/in statement will therefore always throw an exception as follows:

babel -d dist src
TypeError: src/bar.js: Cannot read property 'Symbol(Symbol.iterator)' of undefined
    at Object.UpdateExpression