Error stack strawman

[Boris Zbarsky]

On 2/24/16 4:30 PM, Mark S. Miller wrote:
> [1] For some reason the FF stack accessor has both getter and setter. I
> don't see any reason for a setter.

We ran into code "in the wild" (more precisely, within our own test 
suite infrastructure, but we have no reason to believe this would not 
happen in the wild) where people were reading error.stack, doing some 
processing on it, and then setting error.stack on that same error, and 
expecting error.stack to be that thing after that.  Clearly this Just 
Works with a value property, across all browsers at that point, so we 
made it work with the accessor too.

-Boris