params modifier applied to Generic Type arguments

[jamescrosswell]

SDKs often have dozens of overloads like this one from SqlLite:

        public virtual void CreateFunction<TState, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult>(string name, TState state, Func<TState, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, TResult>? function, bool isDeterministic = false)
            => CreateFunctionCore(name, 15, state, IfNotNull<TState, TResult>(function, (s, r) => function!(s, r.GetFieldValue<T1>(0)!, r.GetFieldValue<T2>(1)!, r.GetFieldValue<T3>(2)!, r.GetFieldValue<T4>(3)!, r.GetFieldValue<T5>(4)!, r.GetFieldValue<T6>(5)!, r.GetFieldValue<T7>(6)!, r.GetFieldValue<T8>(7)!, r.GetFieldValue<T9>(8)!, r.GetFieldValue<T10>(9)!, r.GetFieldValue<T11>(10)!, r.GetFieldValue<T12>(11)!, r.GetFieldValue<T13>(12)!, r.GetFieldValue<T14>(13)!, r.GetFieldValue<T15>(14)!)), isDeterministic);

This is boring boilerplate code. It distracts the code author and the code reader. It's currently a necessary evil.

This is because the params modifier cannot be use with Generic Type arguments.

What if it could though? What if all of the overloads for CreateFunction above could be consolidated into a single definition like:

CreateFunction<TState, TResult, params T[]>

All of the elements T[0], T[1] etc. would server the same purpose as T1, T2 etc. in the original code.

There's more complexity there to be worked out, like the syntax for specifying generic type constraints on generic params... but I figured I'd check whether this request has been made before and if there are already other extensive discussions on the topic before getting too enthusiastic.

[HaloFour]

See: #2330

[jamescrosswell]

Thanks @HaloFour - I wasn't aware it was referred to as Variadic arguments (TIL) 😄