Use custom base::overload() helper.

Telegram/SourceFiles/apiwrap.cpp

@@ -24,6 +24,7 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 #include "data/data_photo.h"
 #include "data/data_web_page.h"
 #include "core/tl_help.h"
+#include "base/overload.h"
 #include "observer_peer.h"
 #include "lang/lang_keys.h"
 #include "application.h"
@@ -1716,7 +1717,7 @@ void ApiWrap::parseChannelParticipants(
 		const MTPchannels_ChannelParticipants &result,
 		base::lambda<void(int fullCount, const QVector<MTPChannelParticipant> &list)> callbackList,
 		base::lambda<void()> callbackNotModified) {
-	TLHelp::VisitChannelParticipants(result, ranges::overload([&](
+	TLHelp::VisitChannelParticipants(result, base::overload([&](
 			const MTPDchannels_channelParticipants &data) {
 		App::feedUsers(data.vusers);
 		if (callbackList) {

Telegram/SourceFiles/base/overload.h

@@ -0,0 +1,102 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop version of Telegram messaging app, see https://telegram.org
+
+Telegram Desktop is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+It is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+In addition, as a special exception, the copyright holders give permission
+to link the code of portions of this program with the OpenSSL library.
+
+Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
+Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
+*/
+#pragma once
+
+namespace base {
+namespace details {
+
+// This implementation was taken from range-v3 library.
+// It was modified so that more than one of passed function objects
+// could be called with an argument list and the first one that
+// matches gets used instead of a compile-time ambiguity error.
+//
+// This allows to write "default" visitor handlers with [](auto&&) syntax.
+
+template <typename ...Args>
+constexpr bool is_callable_v = rpl::details::is_callable_plain_v<Args...>;
+
+template <typename ...Args>
+struct overloaded;
+
+template <>
+struct overloaded<> {
+};
+
+template <typename First, typename ...Rest>
+struct overloaded<First, Rest...>
+	: private First
+	, private overloaded<Rest...> {
+
+private:
+	using Others = overloaded<Rest...>;
+
+public:
+	overloaded() = default;
+
+	constexpr overloaded(First first, Rest... rest)
+	: First(std::move(first))
+	, Others(std::move(rest)...) {
+	}
+
+	template <typename... Args>
+	auto operator()(Args&&... args)
+	-> decltype(std::declval<First&>()(std::forward<Args>(args)...)) {
+		return static_cast<First&>(*this)(std::forward<Args>(args)...);
+	}
+
+	template <typename... Args>
+	auto operator()(Args&&... args) const
+	-> decltype(std::declval<const First&>()(std::forward<Args>(args)...)) {
+		return static_cast<const First&>(*this)(std::forward<Args>(args)...);
+	}
+
+	template <
+		typename... Args,
+		typename = std::enable_if_t<!is_callable_v<First&, Args&&...>>>
+	auto operator()(Args&&... args)
+	-> decltype(std::declval<Others&>()(std::forward<Args>(args)...)) {
+		return static_cast<Others&>(*this)(std::forward<Args>(args)...);
+	}
+
+	template <
+		typename... Args,
+		typename = std::enable_if_t<!is_callable_v<const First&, Args&&...>>>
+	auto operator()(Args&&... args) const
+	-> decltype(std::declval<const Others&>()(std::forward<Args>(args)...)) {
+		return static_cast<const Others&>(*this)(std::forward<Args>(args)...);
+	}
+
+};
+
+} // namespace details
+
+template <typename Function>
+Function overload(Function &&function) {
+	return std::forward<Function>(function);
+}
+
+template <typename ...Functions, typename = std::enable_if_t<(sizeof...(Functions) > 1)>>
+auto overload(Functions ...functions) {
+	return details::overloaded<Functions...>(std::move(functions)...);
+}
+
+} // namespace base
+

Telegram/SourceFiles/history/history_admin_log_inner.cpp

@@ -36,6 +36,7 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 #include "ui/widgets/popup_menu.h"
 #include "core/file_utilities.h"
 #include "core/tl_help.h"
+#include "base/overload.h"
 #include "lang/lang_keys.h"
 #include "boxes/edit_participant_box.h"
 
@@ -351,7 +352,7 @@ void InnerWidget::requestAdmins() {
 		MTP_int(kMaxChannelAdmins),
 		MTP_int(participantsHash)
 	)).done([this](const MTPchannels_ChannelParticipants &result) {
-		auto readCanEdit = ranges::overload([](const MTPDchannelParticipantAdmin &v) {
+		auto readCanEdit = base::overload([](const MTPDchannelParticipantAdmin &v) {
 			return v.is_can_edit();
 		}, [](auto &&) {
 			return false;

Telegram/SourceFiles/history/history_admin_log_item.cpp

@@ -26,6 +26,7 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 #include "lang/lang_keys.h"
 #include "boxes/sticker_set_box.h"
 #include "core/tl_help.h"
+#include "base/overload.h"
 #include "messenger.h"
 
 namespace AdminLog {
@@ -212,7 +213,7 @@ auto GenerateParticipantChangeTextInner(
 		const MTPChannelParticipant *oldParticipant) {
 	auto oldType = oldParticipant ? oldParticipant->type() : 0;
 
-	auto readResult = ranges::overload([](const MTPDchannelParticipantCreator &data) {
+	auto readResult = base::overload([&](const MTPDchannelParticipantCreator &data) {
 		// No valid string here :(
 		return lng_admin_log_invited__generic(
 			lt_user,
@@ -234,7 +235,7 @@ auto GenerateParticipantChangeTextInner(
 			(oldType == mtpc_channelParticipantBanned)
 				? &oldParticipant->c_channelParticipantBanned().vbanned_rights
 				: nullptr);
-	}, [&](auto &&data) {
+	}, [&](const auto &data) {
 		auto user = GenerateUserString(data.vuser_id);
 		if (oldType == mtpc_channelParticipantAdmin) {
 			return GenerateAdminChangeText(

Telegram/SourceFiles/profile/profile_channel_controllers.cpp

@@ -25,6 +25,7 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 #include "boxes/confirm_box.h"
 #include "boxes/add_contact_box.h"
 #include "core/tl_help.h"
+#include "base/overload.h"
 #include "auth_session.h"
 #include "apiwrap.h"
 #include "lang/lang_keys.h"
@@ -1080,7 +1081,7 @@ void ParticipantsBoxSearchController::searchDone(
 	}
 
 	_requestId = 0;
-	TLHelp::VisitChannelParticipants(result, ranges::overload([&](
+	TLHelp::VisitChannelParticipants(result, base::overload([&](
 			const MTPDchannels_channelParticipants &data) {
 		auto &list = data.vparticipants.v;
 		if (list.size() < requestedCount) {
@@ -1716,7 +1717,7 @@ void AddParticipantBoxSearchController::searchParticipantsDone(mtpRequestId requ
 		return;
 	}
 	_requestId = 0;
-	TLHelp::VisitChannelParticipants(result, ranges::overload([&](
+	TLHelp::VisitChannelParticipants(result, base::overload([&](
 			const MTPDchannels_channelParticipants &data) {
 		auto &list = data.vparticipants.v;
 		if (list.size() < requestedCount) {

Telegram/SourceFiles/rpl/lifetime.h

@@ -52,9 +52,9 @@ public:
 	template <typename Type, typename... Args>
 	Type *make_state(Args&& ...args) {
 		auto result = new Type(std::forward<Args>(args)...);
-		add([result]() mutable {
+		add([result] {
 			static_assert(sizeof(Type) > 0, "Can't delete unknown type.");
-			delete details::take(result);
+			delete result;
 		});
 		return result;
 	}

Telegram/SourceFiles/window/window_peer_menu.cpp

@@ -510,7 +510,7 @@ void PeerMenuAddChannelMembers(not_null<ChannelData*> channel) {
 				return App::userLoaded(userId);
 			}) | ranges::view::filter([](UserData *user) {
 				return (user != nullptr);
-			});
+			}) | ranges::to_vector;
 
 			AddParticipantsBoxController::Start(
 				channel,

Telegram/gyp/telegram_sources.txt

@@ -14,6 +14,7 @@
 <(src_loc)/base/ordered_set.h
 <(src_loc)/base/openssl_help.h
 <(src_loc)/base/optional.h
+<(src_loc)/base/overload.h
 <(src_loc)/base/parse_helper.cpp
 <(src_loc)/base/parse_helper.h
 <(src_loc)/base/qthelp_regex.h