frontend: Remove implicit capture of "this" using "="

Implicitly capturing "this" with the capture default "=" is deprecated
with C++20. We fix this by either explicitly passing this, or by copying
the required members manually.
While this exposes some rather expensive copies like the QList
selectedItems in OBSBasic_Preview, it doesn't introduce them ("=" copies
implicitly).

frontend/settings/OBSBasicSettings.cpp

@@ -2835,7 +2835,7 @@ void OBSBasicSettings::LoadHotkeySettings(obs_hotkey_id ignoreKey)
 		}
 
 		hotkeys.emplace_back(registerer_type == OBS_HOTKEY_REGISTERER_FRONTEND, hw);
-		connect(hw, &OBSHotkeyWidget::KeyChanged, this, [=]() {
+		connect(hw, &OBSHotkeyWidget::KeyChanged, this, [this, hotkeysLayout]() {
 			HotkeysChanged();
 			ScanDuplicateHotkeys(hotkeysLayout);
 		});

frontend/utility/AdvancedOutput.cpp

@@ -624,7 +624,8 @@ std::shared_future<void> AdvancedOutput::SetupStreaming(obs_service_t *service,
 	const char *audio_encoder_id = config_get_string(main->Config(), "AdvOut", "AudioEncoder");
 	int streamTrackIndex = config_get_int(main->Config(), "AdvOut", "TrackIndex") - 1;
 
-	auto handle_multitrack_video_result = [=](std::optional<bool> multitrackVideoResult) {
+	auto handle_multitrack_video_result = [this, type = std::string{type}, is_multitrack_output,
+					       multiTrackAudioMixes](std::optional<bool> multitrackVideoResult) {
 		if (multitrackVideoResult.has_value())
 			return multitrackVideoResult.value();
 
@@ -635,12 +636,9 @@ std::shared_future<void> AdvancedOutput::SetupStreaming(obs_service_t *service,
 			startStreaming.Disconnect();
 			stopStreaming.Disconnect();
 
-			streamOutput = obs_output_create(type, "adv_stream", nullptr, nullptr);
+			streamOutput = obs_output_create(type.c_str(), "adv_stream", nullptr, nullptr);
 			if (!streamOutput) {
-				blog(LOG_WARNING,
-				     "Creation of stream output type '%s' "
-				     "failed!",
-				     type);
+				blog(LOG_WARNING, "Creation of stream output type '%s' failed!", type.c_str());
 				return false;
 			}
 

frontend/utility/BasicOutputHandler.cpp

@@ -532,7 +532,7 @@ std::shared_future<void> BasicOutputHandler::SetupMultitrackVideo(obs_service_t
 		return continuation(true);
 	};
 
-	QThreadPool::globalInstance()->start([=, multitrackVideo = multitrackVideo.get(),
+	QThreadPool::globalInstance()->start([=, main = main, multitrackVideo = multitrackVideo.get(),
 					      service_name = std::string{service_name}, service = OBSService{service},
 					      stream_dump_config = OBSData{stream_dump_config},
 					      start_streaming_guard = start_streaming_guard]() mutable {

frontend/utility/SimpleOutput.cpp

@@ -610,7 +610,8 @@ std::shared_future<void> SimpleOutput::SetupStreaming(obs_service_t *service, Se
 	auto audio_bitrate = GetAudioBitrate();
 	auto vod_track_mixer = IsVodTrackEnabled(service) ? std::optional{1} : std::nullopt;
 
-	auto handle_multitrack_video_result = [=](std::optional<bool> multitrackVideoResult) {
+	auto handle_multitrack_video_result = [this, type = std::string{type},
+					       service](std::optional<bool> multitrackVideoResult) {
 		if (multitrackVideoResult.has_value())
 			return multitrackVideoResult.value();
 
@@ -621,12 +622,9 @@ std::shared_future<void> SimpleOutput::SetupStreaming(obs_service_t *service, Se
 			startStreaming.Disconnect();
 			stopStreaming.Disconnect();
 
-			streamOutput = obs_output_create(type, "simple_stream", nullptr, nullptr);
+			streamOutput = obs_output_create(type.c_str(), "simple_stream", nullptr, nullptr);
 			if (!streamOutput) {
-				blog(LOG_WARNING,
-				     "Creation of stream output type '%s' "
-				     "failed!",
-				     type);
+				blog(LOG_WARNING, "Creation of stream output type '%s' failed!", type.c_str());
 				return false;
 			}
 

frontend/widgets/OBSBasic_Preview.cpp

@@ -493,7 +493,7 @@ void OBSBasic::ColorChange()
 				}
 			};
 
-			auto changedColor = [=](const QColor &color) {
+			auto changedColor = [this, selectedItems](const QColor &color) {
 				if (color.isValid()) {
 					ConfirmColor(ui->sources, color, selectedItems);
 				}