10$: Warn on let ({x} = y);

[strager]

Before refactor:

let x;
({x} = y);

After refactor:

let ({x} = y);  // Bug! This uses an undeclared variable 'x' and calls a function named 'let'.

Conditions for this diagnostic:

• Function call with a variable let as the callee.
• Exactly one function argument.
• Function argument is an assignment expression with =.
• Function argument's left-hand side is an object literal.

[msharipov]

@strager Shouldn't this be considered an error? Code like this crashes in Node.js on line 5:

const y = {x: 45, z: "helloworld"};
let z;
({z} = y);
console.log(z);
let ({x} = y);
console.log(x);

[strager]

@msharipov This doesn't crash:

const y = {x: 45, z: "helloworld"};
let z;
({z} = y);
console.log(z);

function let(arg) {
  console.log("let", arg);
}
let x;
let ({x} = y);
console.log(x);

[msharipov]

@strager Ah, I see. Could you please assign this to me?

[Nyx1on]

I claim this for-hire task. I expect payment after I complete this task. I will email the quick-lint-js team if I am assigned this task.

[strager]

@Nyx1on Someone else already claimed this task. If @msharipov is unresponsive, I'll give the task you @Nyx1on.

[msharipov]

I'm still working on this, it's just taking a while.