Operator overloading -- lets collect some use cases

[Don]

Weed wrote:
> Frits van Bommel пишет:
>> Don wrote:
>>> Frits van Bommel wrote:
>>>> Don wrote:
>>>>> A straightforward first step would be to state in the spec that "the
>>>>> compiler is entitled to assume that X+=Y yields the same result as
>>>>> X=X+Y"
>>>> That doesn't hold for reference types, does it?
>>> I thought it does? Got any counter examples?
>> For any class type, with += modifying the object and + returning a new one:
> 
> The += operator too should return the object (usually "this")

ALWAYS 'this'. It's another feature of operator overloading which is 
redundant.