Method fail

Telegram/SourceFiles/export/export_api_wrap.cpp:317–331

template <typename Request>
auto ApiWrap::RequestBuilder<Request>::fail(
	Fn<bool(const MTP::Error &)> &&handler
) -> RequestBuilder& {
	if (handler) {
		[[maybe_unused]] auto &silence_warning = _builder.fail([
			common = base::take(_commonFailHandler),
			specific = std::move(handler)
		](const MTP::Error &error) {
			if (!specific(error)) {
				common(error);
			}
		});
	}
	return *this;
}

template <typename Request>
mtpRequestId ApiWrap::RequestBuilder<Request>::send() {