IOperation API for anonymous object creation expressions

[mavasani]

Two possible approaches:

1. Expose two separate arrays for declared property symbols and arguments:

    public interface IAnonymousObjectCreationExpression : IHasArgumentsExpression
    {
        ImmutableArray<IPropertySymbol> DeclaredProperties { get; }
    }

2. Expose a single array of property initializers, each with declared symbol and initializer:

    public interface IAnonymousObjectCreationExpression : IOperation
    {
        ImmutableArray<IAnonymousPropertyInitializer> Initializers { get; }
    }

    public interface IAnonymousPropertyInitializer : IOperation
    {
        IPropertySymbol DeclaredProperty { get; }
        IOperation Initializer { get; }
    }

[CyrusNajmabadi]

Design Team Decision

public interface IAnonymousObjectCreationExpression : IOperation
    {
        ImmutableArray<IAssignmentExpression> Initializers { get; }  // or
        ImmutableArray<IOperation> Initializers { get; }
    }

---

If we use AssignmentExpression we need to have a IOperation for the left side. This will be a PropertyReferenceExpression. HOwever, because we don't have an appropriate 'receiver' (since we're inside creating the anonymous expression), we'll just use 'null' as the receiver and doc this.