Target any partial method.

[otac0n]

In order to support attribute-based additive source generation, it would be helpful to be able to express any combination of namespace, class, nested class, and partial method with a simple declaration.

@namespace A.B.C
@className ExposedClass+X+Y
@methodName Method

could imply

namespace A.B.C
{
    partial class ExposedClass
    {
        partial class X
        {
                partial class Y
                {
                    Method() {}
                }
        }
    }
}

Better yet,

@memberName A.B.C.ExposedClass+X+Y.Method

Would imply the same.

[otac0n]

Can we target every generic class?

[otac0n]

I think it's too complicated to deal with inheriting values (especially recursively) if we add a @memberName option. Best is to just enable the @className to contain nested class names.