.NET decompiler distinction between "using" and "try...finally" : <p>Given the following C# code in which the <em>Dispose</em> method is called in two different ways:</p>

<pre><code>class Disposable : IDisposable
{
    public void Dispose()
    {
    }
}

class Program
{
    static void Main(string[] args)
    {
        using (var disposable1 = new Disposable())
        {
            Console.WriteLine("using");
        }

        var disposable2 = new Disposable();
        try
        {
            Console.WriteLine("try");
        }
        finally
        {
            if (disposable2 != null)
                ((IDisposable)disposable2).Dispose();
        }
    }
}
</code></pre>

<p>Once compiled using release configuration then disassembled with ildasm, the MSIL looks like this:</p>

<pre><code>.method private hidebysig static void  Main(string[] args) cil managed
{
  .entrypoint
  // Code size       57 (0x39)
  .maxstack  1
  .locals init ([0] class ConsoleApplication9.Disposable disposable2,
           [1] class ConsoleApplication9.Disposable disposable1)
  IL_0000:  newobj     instance void ConsoleApplication9.Disposable::.ctor()
  IL_0005:  stloc.1
  .try
  {
    IL_0006:  ldstr      "using"
    IL_000b:  call       void [mscorlib]System.Console::WriteLine(string)
    IL_0010:  leave.s    IL_001c
  }  // end .try
  finally
  {
    IL_0012:  ldloc.1
    IL_0013:  brfalse.s  IL_001b
    IL_0015:  ldloc.1
    IL_0016:  callvirt   instance void [mscorlib]System.IDisposable::Dispose()
    IL_001b:  endfinally
  }  // end handler
  IL_001c:  newobj     instance void ConsoleApplication9.Disposable::.ctor()
  IL_0021:  stloc.0
  .try
  {
    IL_0022:  ldstr      "try"
    IL_0027:  call       void [mscorlib]System.Console::WriteLine(string)
    IL_002c:  leave.s    IL_0038
  }  // end .try
  finally
  {
    IL_002e:  ldloc.0
    IL_002f:  brfalse.s  IL_0037
    IL_0031:  ldloc.0
    IL_0032:  callvirt   instance void [mscorlib]System.IDisposable::Dispose()
    IL_0037:  endfinally
  }  // end handler
  IL_0038:  ret
} // end of method Program::Main
</code></pre>

<p>How does a .NET decompiler such as <em>DotPeek</em> or <em>JustDecompile</em> make the difference between <em>using</em> and <em>try...finally</em>?</p>
