"Alternate Names" aka pseudo-prerequisites. E7 and MSLO can be built again.

OpenRa.Game/Chrome.cs

@@ -751,9 +751,7 @@ namespace OpenRa.Game
 			if (!Rules.TechTree.CanBuild(info, Game.LocalPlayer, buildings))
 			{
 				var prereqs = buildable.Prerequisites
-					.Select(a => Rules.NewUnitInfo[a.ToLowerInvariant()].Traits.Get<BuildableInfo>())
+					.Select( a => Description( a ) );
-					.Where( u => u.Owner.Any( o => o == Game.LocalPlayer.Race ) )
-					.Select( a => a.Description );
 				renderer.DrawText("Requires {0}".F( string.Join( ", ", prereqs.ToArray() ) ), p.ToInt2(),
 					Color.White);
 			}
@@ -765,6 +763,14 @@ namespace OpenRa.Game
 			}
 		}
 
+		private static string Description( string a )
+		{
+			if( a[ 0 ] == '@' )
+				return "any " + a.Substring( 1 );
+			else
+				return Rules.NewUnitInfo[ a.ToLowerInvariant() ].Traits.Get<BuildableInfo>().Description;
+		}
+
 		void DrawSupportPowers()
 		{
 			var numPowers = Game.LocalPlayer.SupportPowers.Values

OpenRa.Game/GameRules/TechTree.cs

@@ -25,7 +25,13 @@ namespace OpenRa.Game.GameRules
 		{
 			var ret = new Cache<string, List<Actor>>( x => new List<Actor>() );
 			foreach( var b in Game.world.Actors.Where( x => x.Owner == player && x.Info != null && x.Info.Traits.Contains<BuildingInfo>() ) )
+			{
 				ret[ b.Info.Name ].Add( b );
+				var buildable = b.Info.Traits.GetOrDefault<BuildableInfo>();
+				if( buildable != null )
+					foreach( var alt in buildable.AlternateName )
+						ret[ alt ].Add( b );
+			}
 			return ret;
 		}
 

OpenRa.Game/Traits/Buildable.cs

@@ -16,6 +16,7 @@ namespace OpenRa.Game.Traits
 		public readonly string Description = "";
 		public readonly string LongDesc = "";
 		public readonly string Icon = null;
+		public readonly string[] AlternateName = { };
 	}
 
 	class Buildable { }

RulesConverter/Program.cs

@@ -81,7 +81,8 @@ namespace RulesConverter
 					{ "Cost", "Cost" },
 					{ "Icon", "Icon" },
 					{ "Description", "Description" },
-					{ "LongDesc", "LongDesc" } }
+					{ "LongDesc", "LongDesc" },
+					{ "AlternateName", "AlternateName" } }
 				},
 
 				{ "Cargo", new PL { 

ra.yaml

@@ -879,7 +879,7 @@ MSLO:
 	Buildable:
 		TechLevel: 13
 		Tab: Defense
-		Prerequisites: stek,atek
+		Prerequisites: @Tech Center
 		Owner: soviet,allies
 		Cost: 2500
 		Description: Missile Silo
@@ -907,6 +907,7 @@ ATEK:
 		Cost: 1500
 		Description: Allied Tech Center
 		LongDesc: Provides Allied advanced technologies.\n  Special Ability: GPS Satellite
+		AlternateName: @Tech Center
 	Selectable:
 		Priority: 3
 	Building:
@@ -1226,6 +1227,7 @@ STEK:
 		Cost: 1500
 		Description: Soviet Tech Center
 		LongDesc: Provides Soviet advanced technologies
+		AlternateName: @Tech Center
 	Selectable:
 		Priority: 3
 	Building:
@@ -2317,7 +2319,7 @@ E7:
 	Buildable:
 		TechLevel: 11
 		Tab: Infantry
-		Prerequisites: atek,stek
+		Prerequisites: @Tech Center
 		Owner: allies,soviet
 		Cost: 1200
 		Description: Tanya

rules.ini

@@ -601,7 +601,7 @@ Infiltrate=yes
 
 ; Tanya
 [E7]
-Prerequisite=atek,stek
+Prerequisite=@Tech Center
 Primary=Colt45
 Secondary=Colt45
 Strength=100
@@ -1228,7 +1228,7 @@ ROT=30
 
 ; big missile silo
 [MSLO]
-Prerequisite=stek,atek
+Prerequisite=@Tech Center
 Primary=none
 Strength=400
 Armor=heavy

units.ini

@@ -353,6 +353,7 @@ Dimensions=2,2
 Footprint=xx xx
 SelectionPriority=3
 LongDesc=Provides Allied advanced technologies.\n  Special Ability: GPS Satellite
+AlternateName=@Tech Center
 [WEAP]
 Description=War Factory
 Traits=Building, RenderBuilding, RenderWarFactory, RallyPoint, Production, IronCurtainable
@@ -448,6 +449,7 @@ Dimensions=3,2
 Footprint=xxx xxx
 SelectionPriority=3
 LongDesc=Provides Soviet advanced technologies
+AlternateName=@Tech Center
 [BARR]
 Description=Soviet Barracks
 Traits=Building, RenderBuilding, RallyPoint, Production, IronCurtainable