enum exhaustiveness checking with --noImplicitReturns doesn't work for nested switches #27388

enum E {
  A = 'A', B = 'B', C = 'C'
};

function one(e: E): number {
  switch (e) {
    case E.A: return 1;
    case E.B: return 2;
    case E.C: return 3;
  }
}

function two(e: E, f: E): number {
  switch (e) {
  case E.A: return 1;
  case E.B: return 2;
  case E.C:
    switch (f!) {
    case E.A: return 31;
    case E.B: return 32;
    case E.C: return 33;
    }
  }
}