terser 5.16.4 will not work properly with webpack4.x

[simo-an]

Bug report or Feature request?

Help wanted.

Version 5.16.4 +

terser input

function num() { return 1 }

function print() {
  let a = num();

  try {
    let b = 2;
    console.warn(b)
  } finally {
    console.warn(a)
  }
}

terser output or error

function num() {
  return 1;
}
function print() {
  let n = num();
  try {
    let n = 2;
    console.warn(n);
  } finally {
    console.warn(n);
  }
}

Due to the update https://github.com/terser/terser/blob/master/CHANGELOG.md#v5164
Output code will use the same var name n

If the output code built with webpack4.x again, the first var n will be removed.

But webpack team think that webpack4.x is not maintained (webpack/webpack#17713 (comment))

is there any suggestions that can solve it? Thanks.