Background and Motivation

As described in #48082 the Operations-API is not usable today for function pointer invocations. This should be changed.

Proposed API

namespace Microsoft.CodeAnalysis.Operations
{
+    public interface IFunctionPointerInvocationOperation : IOperation
+    {
+        IOperation InvokedPointer { get; }
+        ImmutableArray<IArgumentOperation> Arguments { get; }
+    }
}

namespace Microsoft.CodeAnalysis
{
    public enum OperationKind
    {
+        FunctionPointerInvocation = 0x72,
    }
}

Usage Examples

See #48082

Alternative Designs

It would be possible to reuse the IInvocationOperation to represent the function pointer operation. But the usage of this interface has some drawbacks.
For example IsVirtual does not apply to function pointer invocations. In addition we can not model the invoked pointer appropriate.
Therefore we propose the new API.

We could add a property to the interface for retrieving the function pointer method signature as well, rather than requiring the user to do ((IFunctionPointerTypeSymbol)invPointerOperation.InvokedPointer.Type).Signature to get access to the pointer type signature. In addition we could add a property for the function pointer type. But both features could be implemented via extension method, too.

Risks

No knwon risk.