# HG changeset patch
# User alberth <alberth@openttd.org>
# Date 2010-03-07 14:00:53
# Node ID fd229ecdbf78067530bd65a4c5b21927cbbc9f05
# Parent  618888fa16c501b1b8305f2f043f5a1ffc6889dc

(svn r19363) -Codechange: Remove use of _error_message global from TerraformTile_Track.

diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -2723,10 +2723,10 @@ static VehicleEnterTileStatus VehicleEnt
  */
 static CommandCost TestAutoslopeOnRailTile(TileIndex tile, uint flags, uint z_old, Slope tileh_old, uint z_new, Slope tileh_new, TrackBits rail_bits)
 {
-	if (!_settings_game.construction.build_on_slopes || !AutoslopeEnabled()) return CMD_ERROR;
+	if (!_settings_game.construction.build_on_slopes || !AutoslopeEnabled()) return_cmd_error(STR_ERROR_MUST_REMOVE_RAILROAD_TRACK);
 
 	/* Is the slope-rail_bits combination valid in general? I.e. is it safe to call GetRailFoundation() ? */
-	if (CheckRailSlope(tileh_new, rail_bits, TRACK_BIT_NONE, tile).Failed()) return CMD_ERROR;
+	if (CheckRailSlope(tileh_new, rail_bits, TRACK_BIT_NONE, tile).Failed()) return_cmd_error(STR_ERROR_MUST_REMOVE_RAILROAD_TRACK);
 
 	/* Get the slopes on top of the foundations */
 	z_old += ApplyFoundationToSlope(GetRailFoundation(tileh_old, rail_bits), &tileh_old);
@@ -2740,13 +2740,15 @@ static CommandCost TestAutoslopeOnRailTi
 		case TRACK_BIT_UPPER: track_corner = CORNER_N; break;
 
 		/* Surface slope must not be changed */
-		default: return (((z_old != z_new) || (tileh_old != tileh_new)) ? CMD_ERROR : CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]));
+		default:
+			if (z_old != z_new || tileh_old != tileh_new) return_cmd_error(STR_ERROR_MUST_REMOVE_RAILROAD_TRACK);
+			return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
 	}
 
 	/* The height of the track_corner must not be changed. The rest ensures GetRailFoundation() already. */
 	z_old += GetSlopeZInCorner(RemoveHalftileSlope(tileh_old), track_corner);
 	z_new += GetSlopeZInCorner(RemoveHalftileSlope(tileh_new), track_corner);
-	if (z_old != z_new) return CMD_ERROR;
+	if (z_old != z_new) return_cmd_error(STR_ERROR_MUST_REMOVE_RAILROAD_TRACK);
 
 	CommandCost cost = CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
 	/* Make the ground dirty, if surface slope has changed */
@@ -2767,10 +2769,9 @@ static CommandCost TerraformTile_Track(T
 		/* Is there flat water on the lower halftile, that must be cleared expensively? */
 		bool was_water = (GetRailGroundType(tile) == RAIL_GROUND_WATER && IsSlopeWithOneCornerRaised(tileh_old));
 
-		_error_message = STR_ERROR_MUST_REMOVE_RAILROAD_TRACK;
-
 		/* First test autoslope. However if it succeeds we still have to test the rest, because non-autoslope terraforming is cheaper. */
 		CommandCost autoslope_result = TestAutoslopeOnRailTile(tile, flags, z_old, tileh_old, z_new, tileh_new, rail_bits);
+		autoslope_result.SetGlobalErrorMessage();
 
 		/* When there is only a single horizontal/vertical track, one corner can be terraformed. */
 		Corner allowed_corner;