Bug Generic SystempAPI.Query<T> codegen error

Code (CSharp):

1.  
2. private void SendSpawnRequest<T>(ref SystemState state, ref Singleton singleton) where T : IQueryTypeParameter
3.     {
4.         EntityCommandBuffer ecb = SystemAPI.GetSingletonRW<BeginSimulationEntityCommandBufferSystem.Singleton>().ValueRW.CreateCommandBuffer(state.WorldUnmanaged);
5.  
6.         foreach ((T request, Entity entity) in SystemAPI.Query<T>().WithNone<SendRpcCommandRequest>().WithEntityAccess())
7.         {
8.             // final validation check for client connection to server
9.             if (SystemAPI.HasSingleton<NetworkId>())
10.             {
11.                 // Send T spawn request to the server
12.                 ecb.AddComponent(entity, new SendRpcCommandRequest());
13.             }
14.         }
15.     }
16.  
17.     public struct SpectreSpawnRequest : IRpcCommand, IQueryTypeParameter
18.     {
19.         public FixedString128Bytes PlayerName;
20.     }
21.  
22.     public struct ThirdPersonSpawnRequest : IRpcCommand, IQueryTypeParameter
23.     {
24.         public FixedString128Bytes PlayerName;
25.         public float Delay;
26.     }
27.  
28.  

I have a several of these Send*SpawnRequest methods and I'm attempting to make a generic, but the codegen is throwing an error.
Am I doing something wrong?

`
SGICE002: This error indicates a bug in the DOTS source generators. We'd appreciate a bug report (Help -> Report a Bug...). Thanks! Error message: 'System.InvalidCastException: Unable to cast object of type 'Microsoft.CodeAnalysis.CSharp.Symbols.PublicModel.TypeParameterSymbol' to type 'Microsoft.CodeAnalysis.INamedTypeSymbol'. |--| at Unity.Entities.SourceGen.SystemGenerator.SystemAPI.Query.IdiomaticCSharpForEachDescription.<TryGetQueryDatas>g__TryGetIdiomaticCSharpForEachQueryType|73_0(ITypeSymbol typeSymbol, Location errorLocation) |--| at Unity.Entities.SourceGen.SystemGenerator.SystemAPI.Query.IdiomaticCSharpForEachDescription.TryGetQueryDatas(ICollection`1& queryTypes) |--| at Unity.Entities.SourceGen.SystemGenerator.SystemAPI.Query.IdiomaticCSharpForEachDescription..ctor(SystemDescription systemDescription, QueryCandidate queryCandidate, Int32 numForEachsPreviouslySeenInSystem) |--| at Unity.Entities.SourceGen.SystemGenerator.SystemAPI.Query.IdiomaticCSharpForEachModule.RegisterChangesInSystem(SystemDescription systemDescription) |--| at Unity.Entities.SourceGen.SystemGenerator.SystemGenerator.Execute(GeneratorExecutionContext context)'

 

You have to wait until they make SystemAPI source generetor properly supports generic. Until then, stay away from this kind of generic.

One alternative solution is building the query manually.

On the other hand, you should correct the constraint on T

where T : unmanaged, IComponentData, IQueryTypeParameter

 

Bummer about the waiting game.

Query only has the IQueryTypeParameter constraint, why does it need the others?

public static QueryEnumerable<T1> Query<T1> () where T1 : IQueryTypeParameterr

 

Since I tell you to not do what you're trying to do, my addition on T constraint is for other purpose: the alternative solution.