Maps comparison : same key/value can be used multiple times

[g-traub]

The first value in mapB in the example above is used twice, since the keys are equal.

const mapA = new Map([[{b: 'c'}, 2],[{b: 'c'}, 2]])
const mapB = new Map([[{b: 'c'}, 2], ['foo', 'different']])

deepEqual(mapA, mapB)) // true

Example here : https://runkit.com/g-traub/map-keys-comparison

Using sameValueZero comparison would fix this, but maybe change the current behaviour too much ?
With deep comparison, we would need to make sure the same key/value pair can't be used multiple times.

[planttheidea]

This is definitely an issue. Investigating now.

[planttheidea]

The issue actually appears to be because the value from mapA always find a match in mapB (the first value). I have a setup that uses a local cache to avoid matching previously-matched values, should have a change up shortly.

[planttheidea]

Also, same issue exists on Set. Eesh!

[planttheidea]

FYI I've added you as a collaborator on the project so that you can review the fix.