What should SS: IsSimpleParameterList return for discard binding?

[JLHwung]

Comparing https://tc39.es/ecma262/#sec-static-semantics-issimpleparameterlist with the proposal draft, it seems to me that the IsSimpleParameterList is missing the BindingElement: void arm.

The IsSimpleParameterList SS is only used for disallowing local "use strict" within a function body. c.f. https://github.com/rwaldron/tc39-notes/blob/d0c651b358b361b0855cfe7af9ba0b76cab73949/es7/2015-07/july-29.md#611-the-scope-of-use-strict-with-respect-to-destructuring-in-parameter-lists

I prefer returning false for the BindingElement: void production. While I am aware that doing so could become a refactoring hazard, e.g. function f(_) { "use strict"; } is good but function f(void) { "use strict"; } will throw, I believe local strict directive is only good for transitioning from sloppy mode to strict mode. Once the transition is done, such usage should be phased out eventually. Given that discard binding is a novel syntax, I don't think we should still support local "use strict" directive within f(void) {}.