Avoid naming collision with default array element variable in autofix for no-for-loop rule

[bmish]

Fixes #747. Will also help prepare us for #745.

[fisker]

Please add more cases like https://github.com/sindresorhus/eslint-plugin-unicorn/blob/master/test/catch-error-name.js or
https://github.com/sindresorhus/eslint-plugin-unicorn/blob/master/test/prevent-abbreviations.js

[bmish]

@fisker I added one more test case.

[fisker]

Please fix tests

[bmish]

@fisker thanks a lot for adding additional test cases. I fixed the failure.

[fisker]

I think this is not right.

			for (let i = 0; i < arr.length; i += 1) {
				console.log(arr[1]);
				function foo(element) {
					console.log(element);
				}
			}

It should allow use variable element.

this foo function scope should not included, because it didn't use arr[1], this is why avoidCapture didn't recursive automaticlly.

We need collect scopes from references.

---

BTW: don't squash commits, this makes review harder.

[bmish]

A few questions for you.

1. By arr[1], do you mean arr[i]? The rule doesn't report a violation with arr[1].
2. In your example, I see that we technically can use element as our new array variable name, but wouldn't that be unnecessarily confusing? The no-shadow rule suggests this is bad practice.

[fisker]

1. Yes, arr[1], sorry.
2. Yes no-shadow suggest no variable shadowing, it's default to function, do you use all option? My example is about function scope, but there are other scopes.

This example

for (let i = 0; i < errors.length; i++) {
  console.log(errors[i]);

  try {
    doSomethingThrowError();
  } catch(error) {}
}

After #745 we will fix it to

for (const error_ of errors) {
  console.log(error_);

  try {
    doSomethingThrowError();
  } catch(error) {}
}

I don't want use error_, I can use error.

[fisker]

Anyway, this is not very important, let's keep it this way now.

I'm going to check this PR again.

[bmish]

Thanks for the explanation. I will follow-up with your recommendation if I have a chance.

[fisker]

Thanks for fixing this.