[[...[], 0].x] = [0] should not be a syntax error

[evanw]

I'm the author of esbuild and someone filed a correctness bug against my JavaScript parser: evanw/esbuild#835. Turns out acorn has the same issue, so I'm filing this here too.

Repro with acorn v8.0.5:

eval('[[...[], 0].x] = [0]') // this works fine without an error
require('acorn').parse('[[...[], 0].x] = [0]', { ecmaVersion: 'latest' }) // this throws an error

Running this code gives SyntaxError: Comma is not permitted after the rest element which is unexpected.

[marijnh]

Thanks for reporting that. Attached patch should help with this.