"yield" keyword with no value causes an error

[hegemonic]

According to the ES 2015 spec, a YieldExpression with no value is valid. (You can see some examples in Axel Rauschmayer's article on generators.) However, Espree currently throws an error when it attempts to parse the following code, with generators enabled:

function* asyncFunc() {
    var caller = yield;
}

Changing yield to yield 1 allows parsing to succeed.

[nzakas]

Thanks, I'll take a look.

[nzakas]

Working on this.