The following is not allowed by the ES6 grammar: ``` ts function foo(...[a]) { } var [...[b, c]] = [0, 1, 2]; ``` The relevant grammar production is: ``` BindingRestElement[Yield, GeneratorParameter] : [+GeneratorParameter] ... BindingIdentifier[Yield] [~GeneratorParameter] ... BindingIdentifier[?Yield] ``` And a BindingIdentifier does not include a binding pattern.