Bug with for-cycle

[kobezzza]

var foo = {bar: 1};

for (let key in foo) {
    for (let key in foo) {
    }
}

=>

var foo = {bar: 1};

for (var key in foo) {
    for (var key$0 = void 0 in foo) { // WARNING - Parse error. for-in statement should not have initializer
    }
}

es6-transpiler 0.7.17