<select> is broken when options values are bound to Dates

[shameleo]

Version

2.5.16

Reproduction link

https://jsfiddle.net/azpxdt3a/1/

Steps to reproduce

Try select any item except first one.

What is expected?

Item selected.

What is actually happening?

always shows first item. Once any item except first is selected, it's no more possible to select first one (actually, it's possible, as shows correct selected item after the same item was selected twice in a row)

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It seems the bug was introduced in ver 2.4.2. Does not reproduced with objects instead of dates: https://jsfiddle.net/pr847ek7/

[w3cj]

After looking into it, looseEqual does not handle dates correctly.

https://github.com/vuejs/vue/blob/dev/src/shared/util.js#L273

I added a check for dates in looseEqual, but not sure if this is the best way to go about it. Could use a second pair of eyes. 👀