Background and Motivation

C# Hot Reload added a new CreateNewOnMetadataUpdateAttribute attribute, which creates a new type without any limitations. This will be heavily used in Comet. When the new types are sent to the Framework, we need a way to identify the original type it is replacing.

Proposed API

Let's add an attribute to the new generated types that will specify the original type it is replacing. This will be automatically applied during the diff creation.

[OriginalType(string fullName)]

Now at runtime, a library framework can check which type is being replaced, by querying the attribute.