The good answer to 'constness' is spec#. The 'constness', the 'nonnullness', the 'checkedexceptionness' , the 'immutabilityness' etc ... are all describable with contracts. I think Spec# will be a real revolution in the .NET world. In fact the .NET infrastructure should evolve to include contract metadata so that every .NET language will manage contracts in a similar way. Try it here http://research.microsoft.com/SpecSharp/[^] ... and cry because I am sure that c#4 won't include spec# :-(