CAERIUS001 — Type must be sealed
Severity: Error Category: CaeriusNet.Generator Applies to: [GenerateDto], [GenerateTvp]
Cause
A type decorated with [GenerateDto] or [GenerateTvp] is not declared sealed.
Why
CaeriusNet's source generators emit per-type mappers that bypass virtual dispatch and rely on the exact runtime layout. Allowing inheritance would break the assumption that the generated code can materialise an instance using the primary constructor with no further polymorphism. Sealing the type also gives the JIT additional optimisation room for the hot-path mapping.
How to fix
Add the sealed modifier:
csharp
[GenerateDto]
public sealed partial record FooDto(int Id, string Name);