Codechange: Make use of the improved C++17 emplace_back function.

14 files changed, 22 insertions, 44 deletions

diff --git a/src/bridge_gui.cpp b/src/bridge_gui.cpp
index 44cc99ba3..a69ed7448 100644
--- a/src/bridge_gui.cpp
+++ b/src/bridge_gui.cpp
@@ -433,8 +433,7 @@ void ShowBuildBridgeWindow(TileIndex start, TileIndex end, TransportType transpo
 			type_check = CheckBridgeAvailability(brd_type, bridge_len);
 			if (type_check.Succeeded()) {
 				/* bridge is accepted, add to list */
-				/*C++17: BuildBridgeData &item = */ bl->emplace_back();
-				BuildBridgeData &item = bl->back();
+				BuildBridgeData &item = bl->emplace_back();
 				item.index = brd_type;
 				item.spec = GetBridgeSpec(brd_type);
 				/* Add to terraforming & bulldozing costs the cost of the
diff --git a/src/core/smallmap_type.hpp b/src/core/smallmap_type.hpp
index 931a4848b..744f9fd26 100644
--- a/src/core/smallmap_type.hpp
+++ b/src/core/smallmap_type.hpp
@@ -142,8 +142,7 @@ struct SmallMap : std::vector<std::pair<T, U> > {
 		for (uint i = 0; i < std::vector<Pair>::size(); i++) {
 			if (key == std::vector<Pair>::operator[](i).first) return std::vector<Pair>::operator[](i).second;
 		}
-		/*C++17: Pair &n = */ std::vector<Pair>::emplace_back();
-		Pair &n = std::vector<Pair>::back();
+		Pair &n = std::vector<Pair>::emplace_back();
 		n.first = key;
 		return n.second;
 	}
diff --git a/src/engine.cpp b/src/engine.cpp
index 41849b8a2..311a936ed 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -486,8 +486,7 @@ void EngineOverrideManager::ResetToDefaultMapping()
 	this->clear();
 	for (VehicleType type = VEH_TRAIN; type <= VEH_AIRCRAFT; type++) {
 		for (uint internal_id = 0; internal_id < _engine_counts[type]; internal_id++) {
-			/*C++17: EngineIDMapping &eid = */ this->emplace_back();
-			EngineIDMapping &eid = this->back();
+			EngineIDMapping &eid = this->emplace_back();
 			eid.type            = type;
 			eid.grfid           = INVALID_GRFID;
 			eid.internal_id     = internal_id;
diff --git a/src/fios.h b/src/fios.h
index 6a7b6bf01..259e493b2 100644
--- a/src/fios.h
+++ b/src/fios.h
@@ -119,8 +119,7 @@ public:
 	 */
 	inline FiosItem *Append()
 	{
-		/*C++17: return &*/ this->files.emplace_back();
-		return &this->files.back();
+		return &this->files.emplace_back();
 	}
 
 	/**
diff --git a/src/industry_gui.cpp b/src/industry_gui.cpp
index e54b1b2a4..caa18c8e3 100644
--- a/src/industry_gui.cpp
+++ b/src/industry_gui.cpp
@@ -2625,8 +2625,7 @@ struct IndustryCargoesWindow : public Window {
 		_displayed_industries.set(it);
 
 		this->fields.clear();
-		/*C++17: CargoesRow &row = */ this->fields.emplace_back();
-		CargoesRow &row = this->fields.back();
+		CargoesRow &row = this->fields.emplace_back();
 		row.columns[0].MakeHeader(STR_INDUSTRY_CARGOES_PRODUCERS);
 		row.columns[1].MakeEmpty(CFT_SMALL_EMPTY);
 		row.columns[2].MakeEmpty(CFT_SMALL_EMPTY);
@@ -2641,8 +2640,7 @@ struct IndustryCargoesWindow : public Window {
 		int num_cust = CountMatchingAcceptingIndustries(central_sp->produced_cargo, lengthof(central_sp->produced_cargo)) + houses_accept;
 		int num_indrows = max(3, max(num_supp, num_cust)); // One is needed for the 'it' industry, and 2 for the cargo labels.
 		for (int i = 0; i < num_indrows; i++) {
-			/*C++17: CargoesRow &row = */ this->fields.emplace_back();
-			CargoesRow &row = this->fields.back();
+			CargoesRow &row = this->fields.emplace_back();
 			row.columns[0].MakeEmpty(CFT_EMPTY);
 			row.columns[1].MakeCargo(central_sp->accepts_cargo, lengthof(central_sp->accepts_cargo));
 			row.columns[2].MakeEmpty(CFT_EMPTY);
@@ -2705,8 +2703,7 @@ struct IndustryCargoesWindow : public Window {
 		_displayed_industries.reset();
 
 		this->fields.clear();
-		/*C++17: CargoesRow &row = */ this->fields.emplace_back();
-		CargoesRow &row = this->fields.back();
+		CargoesRow &row = this->fields.emplace_back();
 		row.columns[0].MakeHeader(STR_INDUSTRY_CARGOES_PRODUCERS);
 		row.columns[1].MakeEmpty(CFT_SMALL_EMPTY);
 		row.columns[2].MakeHeader(STR_INDUSTRY_CARGOES_CUSTOMERS);
@@ -2719,8 +2716,7 @@ struct IndustryCargoesWindow : public Window {
 		int num_cust = CountMatchingAcceptingIndustries(&cid, 1) + houses_accept;
 		int num_indrows = max(num_supp, num_cust);
 		for (int i = 0; i < num_indrows; i++) {
-			/*C++17: CargoesRow &row = */ this->fields.emplace_back();
-			CargoesRow &row = this->fields.back();
+			CargoesRow &row = this->fields.emplace_back();
 			row.columns[0].MakeEmpty(CFT_EMPTY);
 			row.columns[1].MakeCargo(&cid, 1);
 			row.columns[2].MakeEmpty(CFT_EMPTY);
diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index 4abbcb3b7..21dc9ffb4 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -1916,8 +1916,7 @@ static ChangeInfoResult StationChangeInfo(uint stid, int numinfo, int prop, Byte
 					tmp_layout.clear();
 					for (;;) {
 						/* no relative bounding box support */
-						/*C++17: DrawTileSeqStruct &dtss = */ tmp_layout.emplace_back();
-						DrawTileSeqStruct &dtss = tmp_layout.back();
+						DrawTileSeqStruct &dtss = tmp_layout.emplace_back();
 						MemSetT(&dtss, 0);
 
 						dtss.delta_x = buf->ReadByte();
@@ -5020,8 +5019,7 @@ static void NewSpriteGroup(ByteReader *buf)
 			/* Loop through the var adjusts. Unfortunately we don't know how many we have
 			 * from the outset, so we shall have to keep reallocing. */
 			do {
-				/*C++17: DeterministicSpriteGroupAdjust &adjust = */ adjusts.emplace_back();
-				DeterministicSpriteGroupAdjust &adjust = adjusts.back();
+				DeterministicSpriteGroupAdjust &adjust = adjusts.emplace_back();
 
 				/* The first var adjust doesn't have an operation specified, so we set it to add. */
 				adjust.operation = adjusts.size() == 1 ? DSGA_OP_ADD : (DeterministicSpriteGroupAdjustOperation)buf->ReadByte();
diff --git a/src/newgrf_commons.cpp b/src/newgrf_commons.cpp
index 8209d675c..64eed8139 100644
--- a/src/newgrf_commons.cpp
+++ b/src/newgrf_commons.cpp
@@ -664,8 +664,7 @@ uint32 NewGRFSpriteLayout::PrepareLayout(uint32 orig_offset, uint32 newgrf_groun
 
 	/* Create a copy of the spritelayout, so we can modify some values.
 	 * Also include the groundsprite into the sequence for easier processing. */
-	/*C++17: DrawTileSeqStruct *result = &*/ result_seq.emplace_back();
-	DrawTileSeqStruct *result = &result_seq.back();
+	DrawTileSeqStruct *result = &result_seq.emplace_back();
 	result->image = ground;
 	result->delta_x = 0;
 	result->delta_y = 0;
@@ -675,8 +674,7 @@ uint32 NewGRFSpriteLayout::PrepareLayout(uint32 orig_offset, uint32 newgrf_groun
 	foreach_draw_tile_seq(dtss, this->seq) {
 		result_seq.push_back(*dtss);
 	}
-	result_seq.emplace_back() /*C++17: .MakeTerminator()*/;
-	result_seq.back().MakeTerminator();
+	result_seq.emplace_back().MakeTerminator();
 	/* Determine the var10 values the action-1-2-3 chains needs to be resolved for,
 	 * and apply the default sprite offsets (unless disabled). */
 	const TileLayoutRegisters *regs = this->registers;
diff --git a/src/saveload/afterload.cpp b/src/saveload/afterload.cpp
index 163ded73c..7d1e70212 100644
--- a/src/saveload/afterload.cpp
+++ b/src/saveload/afterload.cpp
@@ -2924,8 +2924,7 @@ bool AfterLoadGame()
 					cur_skip = prev_tile_skip;
 				}
 
-				/*C++17: uint &this_skip = */ skip_frames.push_back(prev_tile_skip);
-				uint &this_skip = skip_frames.back();
+				uint &this_skip = skip_frames.emplace_back(prev_tile_skip);
 
 				/* The following 3 curves now take longer than before */
 				switch (u->state) {
diff --git a/src/saveload/engine_sl.cpp b/src/saveload/engine_sl.cpp
index 863aabff0..b0b9d02d4 100644
--- a/src/saveload/engine_sl.cpp
+++ b/src/saveload/engine_sl.cpp
@@ -191,8 +191,7 @@ static void Load_EIDS()
 	_engine_mngr.clear();
 
 	while (SlIterateArray() != -1) {
-		/*C++17: EngineIDMapping *eid = &*/ _engine_mngr.emplace_back();
-		EngineIDMapping *eid = &_engine_mngr.back();
+		EngineIDMapping *eid = &_engine_mngr.emplace_back();
 		SlObject(eid, _engine_id_mapping_desc);
 	}
 }
diff --git a/src/saveload/waypoint_sl.cpp b/src/saveload/waypoint_sl.cpp
index 4117a591e..663c61f6a 100644
--- a/src/saveload/waypoint_sl.cpp
+++ b/src/saveload/waypoint_sl.cpp
@@ -192,8 +192,7 @@ static void Load_WAYP()
 	int index;
 
 	while ((index = SlIterateArray()) != -1) {
-		/*C++17: OldWaypoint *wp = &*/ _old_waypoints.emplace_back();
-		OldWaypoint *wp = &_old_waypoints.back();
+		OldWaypoint *wp = &_old_waypoints.emplace_back();
 
 		wp->index = index;
 		SlObject(wp, _old_waypoint_desc);
diff --git a/src/settingsgen/settingsgen.cpp b/src/settingsgen/settingsgen.cpp
index 764f370bd..b2a3c76f6 100644
--- a/src/settingsgen/settingsgen.cpp
+++ b/src/settingsgen/settingsgen.cpp
@@ -118,8 +118,7 @@ public:
 			text += stored_size;
 		}
 		while (length > 0) {
-			/*C++17: OutputBuffer &block =*/ this->output_buffer.emplace_back();
-			OutputBuffer &block = this->output_buffer.back();
+			OutputBuffer &block = this->output_buffer.emplace_back();
 			block.Clear(); // Initialize the new block.
 			size_t stored_size = block.Add(text, length);
 			length -= stored_size;
diff --git a/src/stringfilter.cpp b/src/stringfilter.cpp
index 30876a82d..4765a880e 100644
--- a/src/stringfilter.cpp
+++ b/src/stringfilter.cpp
@@ -74,8 +74,7 @@ void StringFilter::SetFilterTerm(const char *str)
 
 		/* Add to word */
 		if (word == nullptr) {
-			/*C++17: word = &*/ this->word_index.push_back({dest, false});
-			word = &this->word_index.back();
+			word = &this->word_index.emplace_back(WordState{ dest, false });
 		}
 
 		memcpy(dest, pos, len);
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index 1a66d530f..47bb34f19 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -710,8 +710,7 @@ CommandCost CmdBuildTunnel(TileIndex start_tile, DoCommandFlag flags, uint32 p1,
 		 * Do this for all tiles (like trees), not only objects. */
 		ClearedObjectArea *coa = FindClearedObject(end_tile);
 		if (coa == nullptr) {
-			/*C++17: coa = &*/ _cleared_object_areas.push_back({end_tile, TileArea(end_tile, 1, 1)});
-			coa = &_cleared_object_areas.back();
+			coa = &_cleared_object_areas.emplace_back(ClearedObjectArea{ end_tile, TileArea(end_tile, 1, 1) });
 		}
 
 		/* Hide the tile from the terraforming command */
diff --git a/src/viewport.cpp b/src/viewport.cpp
index e28a2e606..bf1f34acd 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -498,8 +498,7 @@ static void AddTileSpriteToDraw(SpriteID image, PaletteID pal, int32 x, int32 y,
 {
 	assert((image & SPRITE_MASK) < MAX_SPRITES);
 
-	/*C++17: TileSpriteToDraw &ts = */ _vd.tile_sprites_to_draw.emplace_back();
-	TileSpriteToDraw &ts = _vd.tile_sprites_to_draw.back();
+	TileSpriteToDraw &ts = _vd.tile_sprites_to_draw.emplace_back();
 	ts.image = image;
 	ts.pal = pal;
 	ts.sub = sub;
@@ -708,8 +707,7 @@ void AddSortableSpriteToDraw(SpriteID image, PaletteID pal, int x, int y, int w,
 		return;
 	}
 
-	/*C++17: ParentSpriteToDraw &ps = */ _vd.parent_sprites_to_draw.emplace_back();
-	ParentSpriteToDraw &ps = _vd.parent_sprites_to_draw.back();
+	ParentSpriteToDraw &ps = _vd.parent_sprites_to_draw.emplace_back();
 	ps.x = tmp_x;
 	ps.y = tmp_y;
 
@@ -827,8 +825,7 @@ void AddChildSpriteScreen(SpriteID image, PaletteID pal, int x, int y, bool tran
 
 	*_vd.last_child = (uint)_vd.child_screen_sprites_to_draw.size();
 
-	/*C++17: ChildScreenSpriteToDraw &cs = */ _vd.child_screen_sprites_to_draw.emplace_back();
-	ChildScreenSpriteToDraw &cs = _vd.child_screen_sprites_to_draw.back();
+	ChildScreenSpriteToDraw &cs = _vd.child_screen_sprites_to_draw.emplace_back();
 	cs.image = image;
 	cs.pal = pal;
 	cs.sub = sub;
@@ -847,8 +844,7 @@ void AddChildSpriteScreen(SpriteID image, PaletteID pal, int x, int y, bool tran
 static void AddStringToDraw(int x, int y, StringID string, uint64 params_1, uint64 params_2, Colours colour, uint16 width)
 {
 	assert(width != 0);
-	/*C++17: StringSpriteToDraw &ss = */ _vd.string_sprites_to_draw.emplace_back();
-	StringSpriteToDraw &ss = _vd.string_sprites_to_draw.back();
+	StringSpriteToDraw &ss = _vd.string_sprites_to_draw.emplace_back();
 	ss.string = string;
 	ss.x = x;
 	ss.y = y;