@NotNull
  private Collection<VcsRootError> findExtraMappings(@NotNull List<? extends VcsDirectoryMapping> mappings) {
    Collection<VcsRootError> errors = new ArrayList<>();
    for (VcsDirectoryMapping mapping : mappings) {
      if (!hasVcsChecker(mapping.getVcs())) {
        continue;
      }
      if (!isRoot(mapping)) {
        errors.add(new VcsRootErrorImpl(VcsRootError.Type.EXTRA_MAPPING, mapping));
      }
    }
    return errors;
  }
@NotNull
  private Collection<VcsRootError> findExtraMappings(@NotNull List<? extends VcsDirectoryMapping> mappings)