IOperation API for BoundPointerElementAccesss

[mavasani]

API Proposal

    public interface IPointerElementReferenceExpression : IOperation
    {
        /// <summary>
        /// Pointer to be indexed.
        /// </summary>
        IOperation Expression { get; }
        /// <summary>
        /// Index for the element to reference.
        /// </summary>
        IOperation Index { get; }
        /// <summary>
        /// Boolean indicating if this is a checked expression or not.
        /// </summary>
        bool Checked { get; }
    }

[mavasani]

@jinujoseph We can discuss this one today - I added an API proposal.

[CyrusNajmabadi]

Do we need this if we just hav a general IIndexingOperation?

[CyrusNajmabadi]

The only thing i can see is that this has IsChecked. (though how do you have an unchecked/checked pointer element access)?

[jinujoseph]

Design Team Decision

We should use just same node to represent Array and pointer, call it "IElementIndexingExpression"
We should expose Kind to differentiate both.
Don't expose the Ischecked for now.

[dgrunwald]

What's the status here?
IArrayElementReferenceOperation is public, IPointerIndirectionReferenceOperation is internal.

Also I seem to be getting a NoneOperation for pointer dereferences. These don't even call DefaultVisit in my operation visitor. This results in some rather ugly workarounds: https://github.com/icsharpcode/NullabilityInference/blob/1c436f70152da527e3b30cbfbb81db00afd1a317/NullabilityInference/EdgeBuildingOperationVisitor.cs#L64-L77

I think it would make sense to make IPointerIndirectionReferenceOperation public as-is (without Index or Checked properties), and represent unsafe pointer indexing ptr[i] using two nodes, same as *(ptr + i).