t = 2<<tracebackShift | tracebackAll
	case "crash":
		t = 2<<tracebackShift | tracebackAll | tracebackCrash
	case "wer":
		if GOOS == "windows" {
			t = 2<<tracebackShift | tracebackAll | tracebackCrash
			enableWER()
			break
		}
		fallthrough
	default:
		t = tracebackAll
		if n, ok := atoi(level); ok && n == int(uint32(n)) {
			t |= uint32(n) << tracebackShift
		}
	}