PropertyName doesn't inherit Yield in AssignmentProperty

[jmdyck]

(Following up on #374 (comment) ...)

In the production

    AssignmentProperty[Yield] : PropertyName `:` AssignmentElement[?Yield]

I'm wondering why PropertyName isn't PropertyName[?Yield]. Everywhere else that PropertyName appears, it inherits the setting of the Yield parameter.

I've looked at other places in the grammar where a nonterminal could inherit a parameter-setting but doesn't, and I could generally see why, but not in this case.

And I looked in test262 and didn't find a test that would distinguish the two possibilities.

So I'm thinking it's maybe a bug.

[littledan]

Generally properties can have any keyword name (e.g., return, throw, to take a couple examples used in primordials) so I think this is fine.

[michaelficarra]

@littledan PropertyName only has the Yield flag so it can pass it on to ComputedPropertyName. As you said, it doesn't matter for LiteralPropertyName, which doesn't even accept the flag.

I believe the grammar says

function *g() {
  ({[yield]: x} = y);
}

would not be a valid program, but will become valid if this flag is added. 👍 This change sounds good.

[allenwb]

yup

looks likes like an oversight in the ES6 grammar.

[littledan]

Oh I see, my mistake.