Deployed structured bindings

This doesn't touch cases where `std::tie` was used with `std::ignore`, since there isn't a way to
ignore a variable in structured bindings and choosing a random variable name might trigger unused
variable warnings on CI (will have to confirm that, though).

src/actions/create.cpp

@@ -630,11 +630,8 @@ place_recruit_result place_recruit(unit_ptr u, const map_location &recruit_locat
 			find_recruit_leader(u->side(), recruit_location, recruited_from);
 	u->set_location(recruit_location);
 
-	unit_map::unit_iterator new_unit_itor;
-	bool success = false;
-
 	// Add the unit to the board.
-	std::tie(new_unit_itor, success) = resources::gameboard->units().insert(u);
+	auto [new_unit_itor, success] = resources::gameboard->units().insert(u);
 	assert(success);
 
 	map_location current_loc = recruit_location;

src/actions/move.cpp

@@ -514,10 +514,7 @@ namespace { // Private helpers for move_unit()
 		move_it_->anim_comp().invalidate(disp);
 
 		// Attempt actually moving. Fails if *step_to is occupied.
-		unit_map::unit_iterator unit_it;
-		bool success = false;
-
-		std::tie(unit_it, success) = resources::gameboard->units().move(*move_loc_, *step_to);
+		auto [unit_it, success] = resources::gameboard->units().move(*move_loc_, *step_to);
 
 		if(success) {
 			// Update the moving unit.
@@ -891,11 +888,7 @@ namespace { // Private helpers for move_unit()
 			// Make sure this hex is drawn correctly.
 			disp.invalidate(hex);
 			// Fire sighted events.
-
-			bool wml_undo_blocked = false;
-			bool wml_move_aborted = false;
-
-			std::tie(wml_undo_blocked, wml_move_aborted) = actor_sighted(*ambusher, &sight_cache);
+			auto [wml_undo_blocked, wml_move_aborted] = actor_sighted(*ambusher, &sight_cache);
 			// TODO: should we call post_wml ?
 			wml_move_aborted_ |= wml_move_aborted;
 			wml_undo_disabled_ |= wml_undo_blocked;
@@ -1000,11 +993,7 @@ namespace { // Private helpers for move_unit()
 				// Finish animating.
 				animator.finish(move_it_.get_shared_ptr());
 				// Check for the moving unit being seen.
-
-				bool wml_undo_blocked = false;
-				bool wml_move_aborted = false;
-
-				std::tie(wml_undo_blocked, wml_move_aborted) = actor_sighted(*move_it_, &not_seeing);
+				auto [wml_undo_blocked, wml_move_aborted] = actor_sighted(*move_it_, &not_seeing);
 				// TODO: should we call post_wml ?
 				wml_move_aborted_ |= wml_move_aborted;
 				wml_undo_disabled_ |= wml_undo_blocked;

src/ai/simulated_actions.cpp

@@ -98,11 +98,8 @@ bool simulated_move(int side, const map_location& from, const map_location& to,
 {
 	LOG_AI_SIM_ACTIONS << "Simulated move" << std::endl;
 
-	unit_map::unit_iterator move_unit;
-	bool success = false;
-
 	// In simulation, AI should not know if there is a enemy's ambusher.
-	std::tie(move_unit, success) = resources::gameboard->units().move(from, to);
+	auto [move_unit, success] = resources::gameboard->units().move(from, to);
 
 	if(!success) {
 		// This happened because in some CAs like get_village_phase and move_leader_to_keep phase,
@@ -221,10 +218,7 @@ void helper_place_unit(const unit& u, const map_location& loc){
 	new_unit->heal_fully();
 	new_unit->set_location(loc);
 
-	unit_map::unit_iterator new_unit_itor;
-	bool success = false;
-
-	std::tie(new_unit_itor, success) = resources::gameboard->units().insert(new_unit);
+	auto [new_unit_itor, success] = resources::gameboard->units().insert(new_unit);
 	assert(success);
 
 	if(resources::gameboard->map().is_village(loc)){

src/attack_prediction.cpp

@@ -875,8 +875,7 @@ void prob_matrix::clear()
 			continue;
 		}
 
-		decltype(used_rows_[p].begin()) first_row, last_row;
-		std::tie(first_row, last_row) = std::minmax_element(used_rows_[p].begin(), used_rows_[p].end());
+		auto [first_row, last_row] = std::minmax_element(used_rows_[p].begin(), used_rows_[p].end());
 		for(unsigned int r = *first_row; r <= *last_row; ++r) {
 			for(unsigned int c = 0u; c < cols_; ++c) {
 				plane_[p][r * cols_ + c] = 0.0;

src/formula/formula.cpp

@@ -175,10 +175,7 @@ formula::formula(const std::string& text, function_symbol_table* symbols)
 					std::string str = std::string(tokens.back().begin, tokens.back().end);
 					files.emplace_back(str , 1);
 
-					std::set<std::string>::iterator pos;
-					bool success;
-
-					std::tie(pos, success) = filenames.insert(str);
+					auto [pos, success] = filenames.insert(str);
 
 					if(success) {
 						filenames_it = pos;

src/game_events/wmi_manager.cpp

@@ -204,11 +204,8 @@ void wmi_manager::to_config(config& cfg) const
  */
 void wmi_manager::set_item(const std::string& id, const vconfig& menu_item)
 {
-	auto iter = wml_menu_items_.begin();
-	bool success;
-
 	// First, try to insert a brand new menu item.
-	std::tie(iter, success) = wml_menu_items_.emplace(id, std::make_shared<wml_menu_item>(id, menu_item));
+	auto [iter, success] = wml_menu_items_.emplace(id, std::make_shared<wml_menu_item>(id, menu_item));
 
 	// If an entry already exists, reset it.
 	if(!success) {

src/gui/dialogs/attack_predictions.cpp

@@ -298,8 +298,7 @@ void attack_predictions::draw_hp_graph(drawing& hp_graph, const combatant_data&
 	for(const auto& probability : get_hitpoint_probabilities(attacker.combatant_.hp_dist)) {
 
 		// Get the HP and probability.
-		int hp; double prob;
-		std::tie(hp, prob) = probability;
+		auto [hp, prob] = probability;
 
 		color_t row_color;
 

src/gui/dialogs/preferences_dialog.cpp

@@ -242,10 +242,7 @@ void preferences_dialog::add_friend_list_entry(const bool is_friend, text_box& t
 		username = username.substr(0, pos);
 	}
 
-	acquaintance* entry = nullptr;
-	bool added_new;
-
-	std::tie(entry, added_new) = add_acquaintance(username, (is_friend ? "friend": "ignore"), reason);
+	auto [entry, added_new] = add_acquaintance(username, (is_friend ? "friend": "ignore"), reason);
 
 	if(!entry) {
 		gui2::show_transient_message(_("Error"), _("Invalid username"), "", false, false, true);

src/gui/widgets/settings.cpp

@@ -56,8 +56,7 @@ void update_screen_size_variables()
 	screen_width = rect.w;
 	screen_height = rect.h;
 
-	float scalew, scaleh;
-	std::tie(scalew, scaleh) = vid.get_dpi_scale_factor();
+	auto [scalew, scaleh] = vid.get_dpi_scale_factor();
 	float avgscale = (scalew + scaleh)/2;
 	screen_pitch_microns = MICRONS_PER_INCH / (avgscale * MAGIC_DPI_MATCH_VIDEO);
 

src/picture.cpp

@@ -1018,10 +1018,7 @@ bool exists(const image::locator& i_locator)
 
 	// The insertion will fail if there is already an element in the cache
 	// and this will point to the existing element.
-	auto iter = image_existence_map.begin();
-	bool success;
-
-	std::tie(iter, success) = image_existence_map.emplace(i_locator.get_filename(), false);
+	auto [iter, success] = image_existence_map.emplace(i_locator.get_filename(), false);
 
 	bool& cache = iter->second;
 	if(success) {

src/preferences/game.cpp

@@ -235,11 +235,7 @@ std::pair<preferences::acquaintance*, bool> add_acquaintance(
 	}
 
 	preferences::acquaintance new_entry(nick, mode, notes);
-
-	acquaintances_map::iterator iter;
-	bool success;
-
-	std::tie(iter, success) = acquaintances.emplace(nick, new_entry);
+	auto [iter, success] = acquaintances.emplace(nick, new_entry);
 
 	if(!success) {
 		iter->second = new_entry;

src/scripting/lua_unit.cpp

@@ -74,10 +74,7 @@ unit_ptr lua_unit::get_shared() const
 bool lua_unit::put_map(const map_location &loc)
 {
 	if (ptr) {
-		unit_map::unit_iterator unit_it;
-		bool success = false;
-
-		std::tie(unit_it, success) = resources::gameboard->units().replace(loc, ptr);
+		auto [unit_it, success] = resources::gameboard->units().replace(loc, ptr);
 
 		if(success) {
 			ptr.reset();
@@ -530,10 +527,7 @@ static int impl_unit_set(lua_State *L)
 					return luaL_argerror(L, 2, err_msg.c_str());
 				}
 
-				unit_map::iterator unit_iterator = gb->units().end();
-				bool success = false;
-
-				std::tie(unit_iterator, success) = gb->units().move(src, dst);
+				auto [unit_iterator, success] = gb->units().move(src, dst);
 
 				if(success) {
 					unit_iterator->anim_comp().set_standing();

src/tests/test_formula_timespan.cpp

@@ -52,16 +52,14 @@ typedef std::tuple<
 
 inline time_t gen_as_time_t(const time_detailed& params)
 {
-	time_t sec, min, hr, day, wk, mo, yr;
-	std::tie(sec, min, hr, day, wk, mo, yr) = params;
+	auto [sec, min, hr, day, wk, mo, yr] = params;
 
 	return YEAR*yr + MONTH*mo + WEEK*wk + DAY*day + HOUR*hr + MIN*min + SEC*sec;
 }
 
 inline std::string gen_as_str(const time_detailed& params)
 {
-	time_t sec, min, hr, day, wk, mo, yr;
-	std::tie(sec, min, hr, day, wk, mo, yr) = params;
+	auto [sec, min, hr, day, wk, mo, yr] = params;
 
 	std::vector<t_string> bits;
 	std::string res;

src/video.cpp

@@ -299,8 +299,7 @@ SDL_Rect CVideo::screen_area(bool as_pixels) const
 
 	// Then convert the dimensions into screen coordinates, if applicable.
 	if(!as_pixels) {
-		float scale_x, scale_y;
-		std::tie(scale_x, scale_y) = get_dpi_scale_factor();
+		auto [scale_x, scale_y] = get_dpi_scale_factor();
 
 		size.x /= scale_x;
 		size.y /= scale_y;
@@ -464,8 +463,7 @@ std::vector<point> CVideo::get_available_resolutions(const bool include_current)
 
 #if 0
 	// DPI scale factor.
-	float scale_h, scale_v;
-	std::tie(scale_h, scale_v) = get_dpi_scale_factor();
+	auto [scale_h, scale_v] = get_dpi_scale_factor();
 #endif
 
 	// The maximum size to which this window can be set. For some reason this won't