message: Fix bug in deduplicate
diff: @@ -63,7 +63,7 @@ function isDefined<X>(value: X | undefined): value is X {
  function deduplicate<T>(input: ReadonlyArray<T>, comparator: (a: T, b: T) => number): Array<T> {
  const out = new Array<T>();
  for (const element of input) {
  - if (!out.find((o) => comparator(o, element) === 0)) {
  + if (out.find((o) => comparator(o, element) === 0) === undefined) {
  out.push(element);
  }
  }
  