import/export false positive with star reexports

[Jessidhia]

Sample code:

// index.js

export * from './core'
// Placed here to work around a webpack bug.
// https://github.com/webpack/webpack/issues/3588
export { default } from './core'

export * from './modules'

// export { default } from './core';
// disambiguate export
export { api } from './modules'

// (simplified) core.js that can reproduce the issue
export const api = {}
export default null

// (simplified) modules.js that can reproduce the issue
export const api = {}

As the api exports coming via the export * are not SameValue, the lint warning would be correct if not for the export { api } from './modules' at the bottom, which disambiguates the exports.

Explicit exports always take precedence over any star reexports, so no exports are duplicated.

---

Note that, if both export const api were set to, say, 'foo', they would all be SameValue, and so would be allowed by the spec even without the disambiguating reexport. I have no idea how the spec would deal with the case where they are mutable exports 😆

There might be value in actually having a warning for this case, but it probably should be in a separate rule, or configuration option.