C#: Can't compare ButtonIndex property (int) to ButtonList enum value, e.g. ButtonList.Left

[MinimumEntropy]

Godot version: 3.2.2.stable.mono.official

OS/device including version: Windows 10

Issue description:
I wrote C# code to catch the _Input event, then checked for multiple clicks by first casting to InputEventMouseButton with the is keyword, then checking if the InputEventMouseButton's ButtonIndex.Equals(ButtonList.Left). This never was true. However, upon replacing the ButtonList.Left with simply 1, it works perfectly. I find this strange as it works with (for example) WheelUp and WheelDown.

Steps to reproduce: Please simply download below, run, and observe the debugging output! My code is also written below:

using Godot;

public class example : Spatial
{
    public override void _Input(InputEvent inputEvent)
    {
        if (inputEvent is InputEventMouseButton buttonEvent)
        {
            if (buttonEvent.IsPressed()) // limits prints per click to one for readability, can remove if needed
            {
                if (buttonEvent.ButtonIndex.Equals(1)) GD.Print("Mouse Button Pressed Using 1");
                if (buttonEvent.ButtonIndex.Equals(ButtonList.Left)) GD.Print("Mouse Button Pressed Using ButtonList");
            }
        }
    }
}

Minimal reproduction project:
MinimalExampleForButtonListIssue.zip

[akien-mga]

I'm not sure it's a bug, C# probably doesn't auto-cast enum types to int, and buttonEvent.ButtonIndex returns an int and not an enum value. Casting ButtonList.Left to int or buttonEvent.ButtonIndex to ButtonList works fine:

if (buttonEvent.ButtonIndex.Equals(1)) GD.Print("Mouse Button Pressed Using 1");
if (((ButtonList)buttonEvent.ButtonIndex).Equals(ButtonList.Left)) GD.Print("Mouse Button Pressed Using ButtonList (cast as enum)");
if (buttonEvent.ButtonIndex.Equals((int)ButtonList.Left)) GD.Print("Mouse Button Pressed Using ButtonList (cast to int)");

I agree that it's not the best UX wise, but I'm not sure how this can be solved in C#. CC @neikeq

[neikeq]

Can ButtonIndex return anything other than a value from the enum? If not then then it should return ButtonList instead of int.

[neikeq]

This was going to be fixed by #27450. It's pending being salvaged by @aaronfranke. Unless he can't work on it anymore, in which case I would take care of it at some point before 4.0.

[aaronfranke]

I can't salvage #27450 without conflicting with #38054, so I would prefer that be merged first.

[neikeq]

@aaronfranke Yeah, no hurries. 4.0 is still far.

[raulsntos]

This was implemented by #47378