async-to-generator transform does not rename local var called arguments

[overlookmotel]

Input:

// Sloppy mode
function outer() {
  let arguments = 123;
  return async () => arguments;
}

function outer2() {
  let {arguments} = {arguments: 123};
  return async () => arguments;
}

Desired output:

function outer() {
  let _arguments = 123;
  return _asyncToGenerator(function* () {
    return _arguments;
  });
}

function outer2() {
  let { arguments: _arguments2 } = {
    arguments: 123
  };
  return _asyncToGenerator(function* () {
    return _arguments2;
  });
}

Babel REPL

Actual output:

function outer() {
  let arguments = 123;
  return _asyncToGenerator(function* () {
    return _arguments; // <-- `_arguments` does not exist
  });
}

function outer2() {
  let { arguments } = { arguments: 123 };
  return _asyncToGenerator(function* () {
    return _arguments2; // <-- `_arguments2` does not exist
  });
}

This is pretty hard to solve as you may not discover that arguments needs to be renamed until quite deep in the function, and then you'd need to re-traverse the whole block where arguments var is bound to rename all references. Obviously we'd want to avoid all that unless it does need to be renamed.

Also, arguments can be defined after it's used:

const fn = async () => arguments;
if (foo) {
  while (deep) {
    {
      var arguments = 123;
    }
  }
}

or even:

const fn = async () => arguments;
function arguments() {}