Remove anonymous classes from generated C# code

[ZJWCY]

There are many classes with names like "__Anon_xxx" defined in generated C# code, which are not referenced by any code.

So I wonder if these classes are necessary in NativeAOT compile or runtime? And if the awnser is no, maybe it's better to remove them from generated C# code?

[jeswin]

It should not be generating classes which aren't used. Can you share an example?
Also, can you try with the latest tsonic? We have made a lot of improvements in the mean time.

Sorry about the late reply - I just noticed this issue.

[ZJWCY]

I just tried the latest version (0.0.46). The problem is still happening.

Here's my TypeScript code in the entry point source file:

import { Console, DateTimeOffset } from '@tsonic/dotnet/System.js';

Console.WriteLine(DateTimeOffset.UtcNow.ToUnixTimeMilliseconds());

And the generated C# code: (The class named __Anon_d159_0ab8d73f is what I'm confused about.)

// Generated from: Test.ts
// Generated at: 2026-02-13T11:20:39.027Z
// WARNING: Do not modify this file manually

namespace Test
{
    public class __Anon_d159_0ab8d73f
    {
        public required global::System.DateTimeOffset MinValue { get; init; }

        public required global::System.DateTimeOffset MaxValue { get; init; }

        public required global::System.DateTimeOffset UnixEpoch { get; init; }

        public required global::System.DateTimeOffset UtcNow { get; init; }

        public required global::System.DateTimeOffset Now { get; init; }
    }

            [global::Tsonic.Internal.ModuleContainerAttribute]
            public static class Test
            {
                public static void __TopLevel()
                {
                    global::System.Console.WriteLine(global::System.DateTimeOffset.UtcNow.ToUnixTimeMilliseconds());
                }
            }
}

[jeswin]

Ah, now I understand. Thank you for the repro.

Will be fixed tomorrow.

[jeswin]

I looked at some options for fixing this. Here's what's happening.

In @tsonic/dotnet, many CLR static surfaces for structs are modeled as export const X: { ... } with an inline object type listing static properties/methods/constructors. DateTimeOffset is exactly that today. When you import { DateTimeOffset } ..., Tsonic pulls that inline object type into its internal IR, so the lowering pass synthesizes _Anon to represent it.

Later, binding resolution correctly emits global::System.DateTimeOffset.UtcNow..., so the synthetic type becomes unused, but we currently don't dead-strip these generated declarations. The fix will be to add a deterministic unused generated declaration elimination pass so synthesized _Anon types that end up unreferenced are removed from output.

It's doable, but I'm thinking we could do this post v1. There's some work that needs to be done to make sure it's completely safe. But we can keep this open until we fix it.