public static @Nullable VirtualFile findBaseFile(@NotNull VirtualFile file) {
    VersionRootInfo info = getVersionRootInfo(file);
    if (info == null) return null;
    VirtualFile versionRoot = info.versionRoot;
    VirtualFile classRoot = info.classRoot;
    String relativePath = VfsUtilCore.getRelativePath(file, versionRoot);
    if (relativePath == null) return null;
    return classRoot.findFileByRelativePath(relativePath);
  }
public static @Nullable VirtualFile findBaseFile(@NotNull VirtualFile file)