Could this be simplified

[The-Futurist]

This might be judged and edge case by the team (or there are subtleties I'm not considering), but here's what I wanted to mention:

public static R4 GetNode<R, R1, R2, R3, R4>(this ParserRuleContext context) 
    where R : ParserRuleContext 
    where R1 : ParserRuleContext 
    where R2 : ParserRuleContext 
    where R3 : ParserRuleContext 
    where R4 : ParserRuleContext
{
    return context.GetNode<R>().GetNode<R1>().GetNode<R2>().GetNode<R3>().GetNode<R4>();
}

Why is it that we can't simply write:

public static R GetNode<R, R, R, R, R>(this ParserRuleContext context) 
    where R : ParserRuleContext 
{
    return context.GetNode<R>().GetNode<R>().GetNode<R>().GetNode<R>().GetNode<R>();
}

At runtime this is invoked with multiple R that differ but do share the base class R:

var bounds = context.GetNode<StructDefinitionContext,StructNameContext,ConstArrayListContext>();

Perhaps there is way to do this better and I'm not aware?

(this is all part of some tree probing code, GetNode is actually better called GetChildNode in fact. It pertains to cases where we know that there is only ever one child of type <whatever> under each node).

[HaloFour]

Why is it that we can't simply write

C# and the .NET runtime has no concept of variadic generic parameters. Not that I think that would work in your case as you explicitly have five separate generic type parameters and the body depends on that.

[The-Futurist]

So what about a more compact syntax:

public static R4 GetNode<R, R1, R2, R3, R4>(this ParserRuleContext context) where (R,R1,R2,R3,R4) : ParserRuleContext 
{
    return context.GetNode<R>().GetNode<R1>().GetNode<R2>().GetNode<R3>().GetNode<R4>();
}

also, I noticed that I got errors in calls to this method, if I change it to:

public static R4 GetNode<R, R1, R2, R3, R4>(this R context) 
    where R : ParserRuleContext 
    where R1 : ParserRuleContext 
    where R2 : ParserRuleContext 
    where R3 : ParserRuleContext 
    where R4 : ParserRuleContext
{
    return context.GetNode<R>().GetNode<R1>().GetNode<R2>().GetNode<R3>().GetNode<R4>();
}

Since we've constrained R to be a ParseRuleContext this puzzled me...

[HaloFour]

I doubt it comes up nearly often enough in most codebases to be worth a form of shorthand like that.