stride3d/stride · error · InvalidOperationException

Unsupported generic resolution.

Error message

Unsupported generic resolution.

What it means

ResolveGenericsVisitor closes generic types during serialization processing; after visiting, Process checks result.ContainsGenericParameter() and throws this InvalidOperationException if the type still has open generic parameters, meaning the visitor could not produce a closed type.

Solutions

1. Ensure serialized member types are fully closed (List<int> not List<T>)
2. Avoid declaring open generic fields/properties on classes processed for serialization
3. Provide concrete instantiations for all generic parameters used in serializable contracts
4. If the pattern is legitimate, report as an AssemblyProcessor limitation and restructure the contract

Example fix

// before
class MyComponent<T> : SyncScript<T> { public T Data; } // open generic member
// after
class MyComponent : SyncScript<MyComponent.State> { public State Data; } // closed type

bool IsClosed(Type t) => !t.ContainsGenericParameters;
if (!IsClosed(memberType)) throw new InvalidOperationException("Serialize member types must be closed generics");

bool IsClosedGeneric(Type t) => !t.ContainsGenericParameters;

catch (InvalidOperationException ex) when (ex.Message == "Unsupported generic resolution.")
{
    // locate open generic member in the data contract and close it
}

When it happens

Trigger: Serializing a data contract whose type (or member type) is generic and cannot be fully closed by the generic type mapping — e.g. a generic class member or unbound generic parameter reaching the processor.

Common situations: Declaring generic fields/properties on serializable components; open generic types (e.g. typeof(List<>)) in serialized contracts; nested generics spanning assemblies the mapping doesn't cover.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Could not resolve generic arguments
• FixedBuffer attribute is not supported.
• Could not find a load operation right before Interop.Pin
• Could not find a store operation right after Interop.Pin
• Missing mscorlib.dll from assembly

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/dd62120f44da889d. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.AssemblyProcessor/ResolveGenericsVisitor.cs:63

        while (parentContext != null)
        {
            var resolvedType = parentContext.Resolve();
            for (int i = 0; i < resolvedType.GenericParameters.Count; ++i)
            {
                var genericParameter = parentContext.GetElementType().Resolve().GenericParameters[i];
                genericTypeMapping.Add(genericParameter, genericInstanceTypeContext.GenericArguments[i]);
            }
            parentContext = parentContext.Resolve().BaseType;
            if (parentContext is GenericInstanceType)
                genericInstanceTypeContext = parentContext as GenericInstanceType;
        }

        var visitor = new ResolveGenericsVisitor(genericTypeMapping);
        var result = visitor.VisitDynamic(type);

        // Make sure type is closed now
        if (result.ContainsGenericParameter())
            throw new InvalidOperationException("Unsupported generic resolution.");

        return result;
    }

    /// <summary>
    /// Creates a visitor that maps generic parameters from <paramref name="source"/> to <paramref name="target"/>.
    /// Returns null if the source has no generic parameters.
    /// </summary>
    public static ResolveGenericsVisitor? FromMapping(IGenericParameterProvider source, IGenericParameterProvider target)
    {
        if (source.GenericParameters.Count == 0)
            return null;

        var mapping = new Dictionary<TypeReference, TypeReference>();
        for (int i = 0; i < source.GenericParameters.Count; i++)
            mapping[source.GenericParameters[i]] = target.GenericParameters[i];
        return new ResolveGenericsVisitor(mapping);
    }

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