C# 5.0 Program and IL (Null-Conditional Operators in C# 6.0 blog post)

1. Program.cs

namespace CS5
{
	class Program
	{
		static void Main(string[] args)
		{
			var car = new Car();
			int currentSpeed = GetCurrentSpeed(car);
		}

		private static int GetCurrentSpeed(Car car)
		{
			if (car != null && car.Engine != null && car.Engine.ControlUnit != null)
			{
				return car.Engine.ControlUnit.CurrentSpeed;
			}

			return 0;
		}
	}
}

2. IL.cs

// Type: CS5.Program 
// Assembly: CS5, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
// MVID: 44B9560D-616F-4E8B-B099-326D477FE514
// Location: D:\study\b-12\CS5\CS5\bin\Debug\CS5.exe
// Sequence point data from D:\study\b-12\CS5\CS5\bin\Debug\CS5.pdb

.class private auto ansi beforefieldinit 
  CS5.Program
    extends [mscorlib]System.Object
{

  .method private hidebysig static void 
    Main(
      string[] args
    ) cil managed 
  {
    .entrypoint
    .maxstack 1
    .locals init (
      [0] class CS5.Car car,
      [1] int32 currentSpeed
    )

    // [6 3 - 6 4]
    IL_0000: nop          

    // [7 4 - 7 24]
    IL_0001: newobj       instance void CS5.Car::.ctor()
    IL_0006: stloc.0      // car

    // [8 4 - 8 44]
    IL_0007: ldloc.0      // car
    IL_0008: call         int32 CS5.Program::GetCurrentSpeed(class CS5.Car)
    IL_000d: stloc.1      // currentSpeed

    // [9 3 - 9 4]
    IL_000e: ret          

  } // end of method Program::Main

  .method private hidebysig static int32 
    GetCurrentSpeed(
      class CS5.Car car
    ) cil managed 
  {
    .maxstack 2
    .locals init (
      [0] int32 CS$1$0000,
      [1] bool CS$4$0001
    )

    // [12 3 - 12 4]
    IL_0000: nop          

    // [13 4 - 13 76]
    IL_0001: ldarg.0      // car
    IL_0002: brfalse.s    IL_001c
    IL_0004: ldarg.0      // car
    IL_0005: callvirt     instance class CS5.Engine CS5.Car::get_Engine()
    IL_000a: brfalse.s    IL_001c
    IL_000c: ldarg.0      // car
    IL_000d: callvirt     instance class CS5.Engine CS5.Car::get_Engine()
    IL_0012: callvirt     instance class CS5.ControlUnit CS5.Engine::get_ControlUnit()
    IL_0017: ldnull       
    IL_0018: ceq          
    IL_001a: br.s         IL_001d
    IL_001c: ldc.i4.1     
    IL_001d: nop          
    IL_001e: stloc.1      // CS$4$0001

    IL_001f: ldloc.1      // CS$4$0001
    IL_0020: brtrue.s     IL_0036

    // [14 4 - 14 5]
    IL_0022: nop          

    // [15 5 - 15 48]
    IL_0023: ldarg.0      // car
    IL_0024: callvirt     instance class CS5.Engine CS5.Car::get_Engine()
    IL_0029: callvirt     instance class CS5.ControlUnit CS5.Engine::get_ControlUnit()
    IL_002e: callvirt     instance int32 CS5.ControlUnit::get_CurrentSpeed()
    IL_0033: stloc.0      // CS$1$0000
    IL_0034: br.s         IL_003a

    // [18 4 - 18 13]
    IL_0036: ldc.i4.0     
    IL_0037: stloc.0      // CS$1$0000
    IL_0038: br.s         IL_003a

    // [19 3 - 19 4]
    IL_003a: ldloc.0      // CS$1$0000
    IL_003b: ret          

  } // end of method Program::GetCurrentSpeed

  .method public hidebysig specialname rtspecialname instance void 
    .ctor() cil managed 
  {
    .maxstack 8

    IL_0000: ldarg.0      // this
    IL_0001: call         instance void [mscorlib]System.Object::.ctor()
    IL_0006: ret          

  } // end of method Program::.ctor
} // end of class CS5.Program