function mergeData(data, source) {
  var bitmask = data[1],
      srcBitmask = source[1],
      newBitmask = bitmask | srcBitmask,
      isCommon = newBitmask < (WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG | WRAP_ARY_FLAG);

  var isCombo =
    ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_CURRY_FLAG)) ||
    ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_REARG_FLAG) && (data[7].length <= source[8])) ||
    ((srcBitmask == (WRAP_ARY_FLAG | WRAP_REARG_FLAG)) && (source[7].length <= source[8]) && (bitmask == WRAP_CURRY_FLAG));

  // Exit early if metadata can't be merged.
  if (!(isCommon || isCombo)) {
    return data;
  }
  // Use source `thisArg` if available.
  if (srcBitmask & WRAP_BIND_FLAG) {
    data[2] = source[2];
    // Set when currying a bound function.
    newBitmask |= bitmask & WRAP_BIND_FLAG ? 0 : WRAP_CURRY_BOUND_FLAG;
  }
  // Compose partial arguments.
  var value = source[3];
  if (value) {
    var partials = data[3];
    data[3] = partials ? composeArgs(partials, value, source[4]) : value;
    data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : source[4];
  }
  // Compose partial right arguments.
  value = source[5];
  if (value) {
    partials = data[5];
    data[5] = partials ? composeArgsRight(partials, value, source[6]) : value;
    data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : source[6];
  }
  // Use source `argPos` if available.
  value = source[7];
  if (value) {
    data[7] = value;
  }
  // Use source `ary` if it's smaller.
  if (srcBitmask & WRAP_ARY_FLAG) {
    data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
  }
  // Use source `arity` if one is not provided.
  if (data[9] == null) {
    data[9] = source[9];
  }
  // Use source `func` and merge bitmasks.
  data[0] = source[0];
  data[1] = newBitmask;

  return data;
}
Used to detect bad signed hexadecimal string values.