IOperation で遊ぶぞ

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Semantics;

public static class Program
{
    public static void Main(string[] args)
    {
        var source = @"class Program { static void Main(string[] args) { System.Console.WriteLine(""Hello""); } }";
        var tree = CSharpSyntaxTree.ParseText(
            source,
            new CSharpParseOptions().WithFeatures(new[]
            {
                new KeyValuePair<string, string>("IOperation", "")
            })
        );
        var compilation = CSharpCompilation.Create(
            "Test",
            syntaxTrees: new[] { tree },
            references: new[] { MetadataReference.CreateFromFile(@"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\mscorlib.dll") },
            options: new CSharpCompilationOptions(OutputKind.ConsoleApplication)
        );
        var semanticModel = compilation.GetSemanticModel(tree);

        var operation = semanticModel.GetOperation(
            tree.GetRoot().DescendantNodes().FirstOrDefault(x => x is InvocationExpressionSyntax)
        );

        Console.WriteLine(operation.GetType().FullName);
        Console.WriteLine(operation.Kind);

        var callOperation = (IInvocationExpression)operation;

        Console.WriteLine(callOperation.TargetMethod);

        foreach (IArgument arg in callOperation.ArgumentsInParameterOrder)
        {
            Console.WriteLine(arg.Value.Syntax);
        }
    }
}