undefined can be redeclared in function body

[hyp3rflow]

undefined can be redeclared in any scope except global scope, but current output does not respect it.
see also: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined#description

function a() {
  const undefined = 1;
  return undefined;
}

// minified
function a() {
  const e = 1;
}