From dbf56751b7ebf2ba00b4c282c1881ae958d8a5c1 Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter1138@openttd.org>
Date: Tue, 2 Jun 2026 19:19:40 +0100
Subject: [PATCH] Codechange: simplify iteration of track bits (#15668)

---
 src/economy.cpp  |  8 +++-----
 src/rail_cmd.cpp | 13 ++++---------
 2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/src/economy.cpp b/src/economy.cpp
index 8a72596e42..a5161490c0 100644
--- a/src/economy.cpp
+++ b/src/economy.cpp
@@ -485,11 +485,9 @@ void ChangeOwnershipOfCompanyItems(Owner old_owner, Owner new_owner)
 			 * because of different owner of crossing and approaching train */
 			for (const auto tile : Map::Iterate()) {
 				if (IsTileType(tile, TileType::Railway) && IsTileOwner(tile, new_owner) && HasSignals(tile)) {
-					TrackBits tracks = GetTrackBits(tile);
-					do { // there may be two tracks with signals for TRACK_BIT_HORZ and TRACK_BIT_VERT
-						Track track = RemoveFirstTrack(&tracks);
-						if (HasSignalOnTrack(tile, track)) AddTrackToSignalBuffer(tile, track, new_owner);
-					} while (tracks != TRACK_BIT_NONE);
+					for (Track track : SetTrackBitIterator(GetTrackBits(tile))) {
+						if (IsSignalPresent(tile, SignalOnTrack(track))) AddTrackToSignalBuffer(tile, track, new_owner);
+					}
 				} else if (IsLevelCrossingTile(tile) && IsTileOwner(tile, new_owner)) {
 					UpdateLevelCrossing(tile);
 				}
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index b8ce36b8ce..576a90b6df 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -1608,9 +1608,7 @@ CommandCost CmdConvertRail(DoCommandFlags flags, TileIndex tile, TileIndex area_
 				}
 			}
 			if (flags.Test(DoCommandFlag::Execute)) { // we can safely convert, too
-				TrackBits reserved = GetReservedTrackbits(tile);
-				Track     track;
-				while ((track = RemoveFirstTrack(&reserved)) != INVALID_TRACK) {
+				for (Track track : SetTrackBitIterator(GetReservedTrackbits(tile))) {
 					Train *v = GetTrainForReservation(tile, track);
 					if (v != nullptr && !HasPowerOnRail(v->railtypes, totype)) {
 						/* No power on new rail type, reroute. */
@@ -1662,9 +1660,8 @@ CommandCost CmdConvertRail(DoCommandFlags flags, TileIndex tile, TileIndex area_
 					default: // RailTileType::Normal, RailTileType::Signals
 						if (flags.Test(DoCommandFlag::Execute)) {
 							/* notify YAPF about the track layout change */
-							TrackBits tracks = GetTrackBits(tile);
-							while (tracks != TRACK_BIT_NONE) {
-								YapfNotifyTrackLayoutChange(tile, RemoveFirstTrack(&tracks));
+							for (Track track : SetTrackBitIterator(GetTrackBits(tile))) {
+								YapfNotifyTrackLayoutChange(tile, track);
 							}
 						}
 						found_convertible_track = true;
@@ -1824,9 +1821,7 @@ static CommandCost ClearTile_Rail(TileIndex tile, DoCommandFlags flags)
 			/* Is there flat water on the lower halftile that gets cleared expensively? */
 			bool water_ground = (GetRailGroundType(tile) == RailGroundType::HalfTileWater && IsSlopeWithOneCornerRaised(tileh));
 
-			TrackBits tracks = GetTrackBits(tile);
-			while (tracks != TRACK_BIT_NONE) {
-				Track track = RemoveFirstTrack(&tracks);
+			for (Track track : SetTrackBitIterator(GetTrackBits(tile))) {
 				CommandCost ret = Command<Commands::RemoveRail>::Do(flags, tile, track);
 				if (ret.Failed()) return ret;
 				cost.AddCost(ret.GetCost());