`decl_event!` should generate only one struct/type

[bkchr]

Currently decl_event! creates enum RawEvent and type Event = when you have a generic event, but for none-generic events it just generates enum Event.
This needs to be unified, aka just generate enum Event.

As rust automatic trait derives are somewhat broken, the macro will need to implementClone, PartialEq, Eq and RuntimeDebug on it's own. It is required that trait bound will not be put onto the generic parameter itself and instead it needs to be put onto the associated types, so something like this:

enum Event<T> {
    SomeEvent(T::Data),
}

has the following PartialEq bounds:

impl<T: Trait> PartialEq for Event<T> where T::Data: PartialEq

and not:

impl<T: Trait> PartialEq for Event<T> where T: PartialEq

parity-scale-codec does this already automatic and so derive(Encode, Decode) should work without any problems.

The code of the macro can be found here

[herou]

@bkchr Can I work on this ticket?

[bkchr]

@herou theoretically yes, but this will probably be solved by #6877 anyway.

[herou]

@bkchr any other issue which you offer mentorship?

[bkchr]

@herou what is your background? What kind of tasks are you searching for?

[herou]

@bkchr I am a mobile developer (Java), recently (6 months) learning rust, substrate, and blockchain to get my feet into.

[bkchr]

Maybe this one: paritytech/polkadot-sdk#369 ?

[gui1117]

Fixed by #6877