let expression weirdness in FF

let.js

//I don't think that this is working right in Firefox
let c = let (a = getA()) a;
console.log(c, a);            //Logs 1, 0
//Why did it log 0 for "a"?

function getA(){
  return 1;
}
function getB(){
  return 2;
}

let2.js

//I don't think that this is working right in Firefox
let c = let (a = getA(), b = getB()) a + b;
console.log(c, a, b);            //Exception: b is not defined
//Why doesn't the first variable cause an exception. Only #of let variables > 1;

function getA(){
  return 1;
}
function getB(){
  return 2;
}

In the first file, Firefox is forgiving that I am referencing a non-existent variable. In the second file, it is tolerant of the first reference to a non-existing variable, but BARFS on the second reference to a non-existing variable. It should be forgiving on both. #icanhazinconsistency

Glad you shared this with me: there are no let expressions or let statements in ES6, only the declaration form.