NBMsgPack012: [DerivedTypeShape] type must be unique

DerivedTypeShapeAttribute should specify a type that is unique within the scope of the type it is applied to.

Learn more about subtype unions.

Example violations

[DerivedTypeShape(typeof(DerivedType), Tag = 1)]
[DerivedTypeShape(typeof(DerivedType), Tag = 2)] // assigned second alias to a subtype
class BaseType
{
}

class DerivedType : BaseType
{
}

Resolution

Remove the extra alias or assign it to a different type.

[DerivedTypeShape(typeof(DerivedType), Tag = 1)]
class BaseType
{
}

class DerivedType : BaseType
{
}