jsii should reject a member name with the same name as the class

[rix0rrr]

🐛 Bug Report

This has just blocked our pipelines and wasted a lot of Elad's work.

In aws/aws-cdk#9557 and aws/aws-cdk#9584 we added a property called construct to the class Construct.

In C#, this property name gets renamed to Construct, so that the member is now called Construct::Construct. However, that name is not allowed because it is reserved for the constructor (which this is not).

In Java this might be a theoretical issue, but it's not a practical one because class names are always pascal-cased while member names are always camel-cased.

The C# generator thought about this and tries to do something "smart": it renames the class to Construct_, which makes the property name allowed again. However, we now broke backwards compatibility with existing code by renaming a class, which is definitely not the intended behavior.

The only solution is to completely disallow this occurrence in the first place:

• Properties or methods with the same (pascal-cased) name as the class should be disallowed by jsii.

This also means that there is a danger in specifying interfaces -- any of the member names in an interface cannot be used as the class name of the implementing class. Yes, there is a way in C# to still properly implement that interface, but it comes with other undesirable consequences attached:

using System;
					

interface IConstructHaver {
	int Construct { get; set; }
}

class Construct : IConstructHaver {
	int IConstructHaver.Construct { get; set; }
}

public class Program
{
	public static void Main()
	{
		var c = new Construct();
                c.Construct = 3;  // NOT ALLOWED

                // This works, but is weird
		(c as IConstructHaver).Construct = 3;
	}
}

It's probably just pragmatic to disallow this occurrence, regardless of whether the member comes from an interface. It will simplify our analysis to not have to deal with the special case, and devs can always work around any potential future limitations on their own (which should be rare anyway).

Affected Languages

• TypeScript or Javascript
• Python
• Java
• .NET (C#, F#, ...)