static newUnreachable(id, allPrevSegments) {
    const segment = new CodePathSegment(
      id,
      CodePathSegment.flattenUnusedSegments(allPrevSegments),
      false,
    );

    /*
     * In `if (a) return a; foo();` case, the unreachable segment preceded by
     * the return statement is not used but must not be remove.
     */
    CodePathSegment.markUsed(segment);

    return segment;
  }
Creates an unreachable segment that follows given segments.
@param {string} id An identifier.
@param {CodePathSegment[]} allPrevSegments An array of the previous segments.
@returns {CodePathSegment} The created segment.