This code infinitely self-replicates every time Prettier formats it

[nickretallack]

Prettier 1.19.1
Playground link

--parser babel

Input:

export type a =
  | 1
  // prettier-ignore
  // @ts-ignore
  | 2;

Output:

export type a =
  | 1
    // prettier-ignore
    // @ts-ignore
  // prettier-ignore
  // @ts-ignore
  | 2;

Expected behavior:
The number of comments in the input and output should be the same. Instead, it's double. Every time you format it, it doubles.