void (@NotNull FileType fileType) { for (FileType type : myFileTypeManager.getRegisteredFileTypes()) { if (type.getClass() == fileType.getClass()) { throw new AssertionError(type + " is still registered"); } } FileType registered = myFileTypeManager.findFileTypeByName(fileType.getName()); if (registered != null && !(registered instanceof AbstractFileType)) { fail(registered.toString()); } }